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Recently I built an AWD 1953 pickup for a customer which turned out incredible. Ever since then, I’ve had the itch to do another AWD setup. Why not a 3rd gen? This is my log of successes and failures along the way. While I will do an AWD something, it may or may not end up as a 3rd gen as I have a soft spot for 47-55 trucks
I’ve had a nasty LSA/Magnum combo since the days when LSAs were everywhere. I’ll never be able to sell it for what I’ve got in it, so why not use it. +700HP supercharged 6.2L aluminum 6 speed AWD? Hell yeah! There’s a compromise for every choice, so hope this thread shines some light on the issues that I thought would be no big deal, but turned out to be major hurdlesAs I write this, I’m about 9 months deep and just now confident enough in the project to really start spending money/time on it
The rules:
As few custom machined drivetrain pieces as possible. I could probably contact Atlas for a billet AWD t-case, but that’s stupid money for the R&D and machine time
I’d prefer to use a T56 magnum. Not only because I already have one, but because T56 cores and hard parts are becoming more and more scarce. Yes, a SSR 32sp T56 mainshaft is available now, but what about 10 years from now? I’ll most likely do more AWD/4x4 T56 builds in the future and the knowledge gained here will be very helpful
With hindsight, I recommend just paying Texas drivetrain $6k for their 32sp 4x4 T56 and be done with it. The magnum has so many little nuances that it’s cost even as a DIY is exorbitant. For mild/moderate power builds, just use a vanilla C5 T56. Swap the mainshaft for a GTO 27sp version and faceplate to Fbody T56
Lastly, I want to attempt to keep this do-able as an average DIY garage if someone wants to follow my footsteps
This build will be broken up into four phases. Planning these out will be critical to prevent this from being another abandoned project
Planning/Research: This is the least glamorous but most critical. Determine t-case, chassis design, axle types, plan out as many details as possible
Teardown/Mock-up: This is where most projects die. Taking stuff apart and cutting something out is much easier than putting it back
Fab work/Build: The meat of the build
Finishing: Details like wiring, paint/body, plumbing, final assembly etc. This is the most expensive phase and is difficult to plan for
With that set, let’s get started. First up, modify the T56 magnum to 4x4 and select a transfer case. Since I’m using a magnum, it’s a little different
T56’s come in three main flavors
Classic T56- 93-02 Fbody, 2 pc counter shaft
Corvette/GTO/SSR T56, these had triple cone synchros and a few other unique pieces, but largely interchange with classic T56
TR6060, which physically similar outside, the internal components largely are not interchangeable. The mainshaft is the key piece I was interested in
On to the Magnum, it’s TR6060 based and the donor I’m pulling the rear extension housing from is C5 corvette T56. It turns out the countershaft bearing pocket is different. I grabbed two 4L60E 4x4 extension housing from the boneyard and designed a simple adapter plate from ¾” aluminum. The 5” centering hole was the only precision cut on the adapter. The holes were hand drilled. Thankfully, 3 of the C5 and 4L60E holes line up exactly along with matching 5” alignment hubs. Off to the machine shop
Figuring out a shifter is still on the to-do list along with a reverse lock-up mechanism
Transfer case: this took much more effort than expected. First, I’d like to explain the difference between 4WD and AWD from a transfer case design perspective as there isn’t a lot of specifics. Several auto mfrs interchange the definition and some designs kind of blur the lines. A couple models actually incorporate BOTH into the same units
The short answer is an AWD t-case has a center differential vs a 4WD locking the F/R outputs together. Much like a rear axle, the F/R wheels turn at different speeds, mostly in cornering. An AWD T-case will allow the axles some freedom, where as 4WD will not. Drive a 4x4 in a parking lot, feel the front wheels chirp/skip. AWD doesn’t do that
There are four main types of AWD T-case:
Open, these operate much like an open diff axle. If you jacked all 4 wheels up and spun one driveshaft, the opposite DS will spin the opposite direction
EX: NP203 from the 70’s
NP242 from Jeeps/Hummers/Durangos
Coupler locked, these are the most common and are fully self contained units that often do not require any computer help. There are some hybrid systems like what Subaru uses, but most people who think of an AWD t-case will think of these
EX: Syclone/Typhoon/Astro BW4472
Ford BW4404/4410
Escalade NP149
Jeep NV147, 247, 249
Active AWD, these require outside help to function. Without, they’re just simple open units. Often these will use ABS to apply brakes to one corner to maintain similar wheel speed on all corners. On the bright side, stagged wheels are an option for this type. Some OEM systems like Porsche come with staggered F/R wheels. With no ABS to fully use the system, some wheel slip is allowable
EX: Escalade BW 4481/44
Most modern AWD crossovers, BMW, Mercedes etc
Clutch based is the last type, but is often frowned upon for custom builds. Some like Subaru still use a differential and the clutch locks or unlocks as needed. Some like the late Astro/Bravada lock/unlock exclusively via clutch and no differential. These often have a short life span, especially when the AWD is used heavily, EX 4 wheeling. These are in the gray area for AWD as they don’t fit the strict definition, but can still be classified under
Late S10’s, Astros fall under this category
Also worth mentioning is the Electronic Shift on the Fly (ESOF/ESOTF) 4WD. These are locking 4x4 units with no slip F/R but can engage/disengage so quickly that the typical 4x4 wheel hop is not felt. Ford often calls this AWD, but for a custom setup, it’s really 4x4. This was my back-up plan if a coupler based T-case failed. Use a Ford BW4406 with TOD. It activates by an electromagnet. Setting up if/then conditions in a Holley ECU, it can be controlled pretty easily with 2WD override for dyno pulls
A more common example is a Silverado NP 246
With that said, I ended up purchasing A LOT of t-cases trying to find a simple solution. The T56 magnum has a 31sp output shaft, so that’s the start
I purchased/rebuilt a tried and true NV149 from an 02 Escalade. Found a machine shop that recuts the input shaft to 32sp for 4L80E swaps and asked if they’d do a 31sp one for me. They accepted and after 4 months of no progress, they sent it back. Plan B, contact Mark Williams. They’d be happy to do it, had the machine data, BUT had a pretty large minimum order. While their PPU was VERY reasonable, the 12 unit minimum made this endeavor too costly, so that T-case was shelved. I got a second hand 32sp input for the T-case and saved it for a later 4L80E build
Next, I tried the NP242 route from a military H1. I then got a cheap Jeep 242 to steal the 2WD components as the H1/2 units were AWD or 4 Lock only. It was a shifter/gate change. These units are really cool, but the open differential AWD wasn’t what I was looking for. There’s a lot of conflicting information about these and most of the other Jeep AWD t-cases. Quite a few people swore these were coupler based. They are not. Had to buy one and crack it open to find that out for sure
The unit has a really cool center diff. It can fully unlock for 2WD, fully lock for hard 4x4, or become and open diff for overland AWD. It’s all one simple slider into the differential
I purchased a Ford 31sp NP271 input shaft hoping it would swap right in. It did not. The complicated gear meshes/critical dims all fit properly. The front bearing and rear pocket bearings were different. I found out later that Northwest Fab sells these pre-machined to do this exact swap. Hindsight
*Add pics when I find them*
Then, I picked up an Escalade BW4481. I knew it wouldn’t work for this project, but it was $30. It was worth that to satisfy my curiosity of how it works
It's a huge empty case with a long input shaft feeding an open differential. This was done to keep the same external dimensions as the other SUV 4x4 units. GM could reuse the same frame, crossmember, driveshafts etc. It’s an active system based on the ABS. There’s a few classis truck builds using these with mixed results. None really push them for the AWD benefits, just say they have AWD and move on to the next project
Pics
Finally, I found a guy parting a S10 Bravada and snagged the BW4472 and AWD front diff. The same trip, I got an Explorer BW4404. The V8 explorers were 31sp input and a viscous coupler based T-case. Just looking at pics, the two input shafts looked interchangeable. If that were true, then I couple pop a Ford BW4404 input into a Bravada BW4472 and have a 31sp in/32sp out T-case that could handle anything I could throw at it. There’s Typhoon guys pushing DOUBLE the power I’m planning through stock t-cases. This is where I spent the bulk of my time/effort
I opted to not use the vanilla Ford unit because of the tiny output shaft and fixed rear flange. 2010+ Camaro TR6060 guys know all about the weak flange snapping off when really power is ran through it. The ford T-case has an even smaller output. 21sp I think. It's tiny
The guts of both units were surprisingly similar with the rear planetary/ring being directly interchangeable. Unfortunately, the inputs do not interchange. To use the Ford input in the Bravada t-case, the front bearing pocket must be moved backwards. Lots of machining/welding
Instead I opted to use the Bravada output shaft in the Ford t-case. I purchased a NP241 tail section to be turned down, pressed in and welded to the Ford rear case. Another thing I found by having the actual part in my shop is that all the case info about the BW4404 is incorrect. It’s listed in about every source as having a magnesium case. It’s actually aluminum. A boon for me, as the tail is easily welded. My machine shop currently has this
As a final attempt, I tried a late model Express van AWD input. Those BW4473 cases are VERY hard to find and quite expensive. If the inputs swap, it may be worth the extra expense. So, I ordered a replacement input from Rock auto. If it fails, then I'm only out shipping both ways. Much less costly than cracking open an $1800 t-case
Since I’m not certain this will actually work, I decided to use a rusted out 3rd gen shell to mock up on. There’s nothing good left on this car, so why not
Stripped the last few bits, braced the chassis with conduit and cut the floor out I used a trailblazer SS chassis under the 1953 build. They can be found stupid cheap, 2wd/4wd chassis are the same and this one came with a good aluminum 5.3 to recoup some funds. Body off, I only need the front half of the chassis
Test fitting. I did the 5 lug conversion and tested with C5 wheels due to the high positive offset. I also popped on a set of JDW control arms to get camber within reason
I nixed this chassis for two reasons:
The drivetrain sat too high in the car. The LSA lid would be above the hood. Trans/T-case severely limited interior/seat space
The upper control arms were dangerously close to the hood. It wouldn’t be ideal to dent the hood with a balljoint from a small bump
Next I picked up a S10 Blazer chassis. Originally, I didn’t want to use them because they were very narrow up front and the steering box geometry was less than ideal. Steering rack options were sketchy like 3rd gens and the few options were VERY expensive. With the steering obstacle in mind, I decided to try
This one ended up being a ZR2, high and wide chassis (edit:incorrect, it's a normal Blazer 4x4). ZR2's came from the factory with a small suspension lift and the front control arms mounted 2” farther out on both sides, for 4” wider total (more on that later). I mocked-up a 17” GTA wheel and it fit the wheel arch perfectly. The extra width positions them perfectly. Onto the interior, the trans mount is only 2” higher than factory 3rd gen. Definitely workable, since I planned to custom position the drivetrain anyways. I put the 3rd gen strut towers back on and they clear the wheels nicely
With that, I’m ready to begin the custom half-chassis. This will be an enormous undertaking, there is nothing simple about it. Plans:
2x4 tubing for the main frame sections tied all the way back to the 3rd gen LCA’s
Stock s10 suspension/hubs/geometry. May change UCA for full size to clear coil overs
Figure out a coil over conversion to eliminate the S10 torsion bars
Figure out if the steering box will work or if an intrepid CTO rack is required
Figure out if any of my headers will fit or if custom headers will be fabricated
Figure out how to mount a trailblazer front diff to the engine. Either use ZR2 CV axles, or do something custom
Modify the oil pan to clear the TB front diff. Possible oil filter relocate
Figure out a way to connect the new chassis to the old in an easily transferable method. Alignment holes, common fitment etc
Fab new tunnel/tubing to provide support and be minimally invasive to the interior
Tie the new chassis to the 3rd gen without losing structural rigidity
what about a colorado/canyon/H3 GMT355 chassis? They got a version of the 5.3 starting in 2010. a quick google search shows they came with rack and pinion.
the trailblazer uses a GMT360 chassis, so they might be too similar.......
and I *thought* that the later year blazers (02 and up?) 2wd trucks got a rack and pinion, but am not certain of that. its been awhile since I walked through a junkyard to look at that kind of stuff
this project is sweet. thanks for sharing with us.
i think Astro vans were available with AWD back in the day and had a chassis similar to the S-10. i haven't seen one of those vans in forever though.
I wonder about using a trans "package" that is more integrated than a typical domestic 6 speed + T-Case + Drive shafts +Front chunk (which'll have to sit directly under the oil pan?)
What has a 5 or 6 speed, and AWD in a RWD platform? Audi's...I like that configuration b/c no front drive shafts and the front diff and t-case are all integrated into a single case. BUT, the front axle shafts would be too far rearward in a third gen; all audi puts the axle shafts behind the bell housing flange. Same with Subi's -same layout.
Porsche made a stick-shift Cayenne, that'd be a possible option?
What else? There aren't many stick-shift, car based, RWD based AWD platforms. AWD CTS's? Did they make those w/a stick? (EDIT: No)
I think that one major hurdle, for OEM's and for a builder, is that the front diff and the crank shaft, want to be in the same space, roughly. Otherwise you end up with the engine too high in the chassis, like you saw with the TB SS.
Last edited by Tom 400 CFI; 02-17-2024 at 01:28 PM.
what about a colorado/canyon/H3 GMT355 chassis? They got a version of the 5.3 starting in 2010. a quick google search shows they came with rack and pinion.
the trailblazer uses a GMT360 chassis, so they might be too similar.......
and I *thought* that the later year blazers (02 and up?) 2wd trucks got a rack and pinion, but am not certain of that. its been awhile since I walked through a junkyard to look at that kind of stuff
Good luck with the project
Colorados are too wide and no 5 lug options. My goal is the use 17" GTA repop wheels to look original from a glance
They also sit the engine very high compared to the frame. PS drop t-case also makes life hard
S10 blazers are all drag link. All TB/Colorado chassis are R&P
I'd love to use the TB chassis, but it just doesn't fit the relatively small 3rd gen
I wasn't sold on the S10 blazer chassis either for reasons above, but the ZR2 bits stretch the width to something more useful. It has a number of drawbacks for sure, but in the spirit of the build, it seems the most promising so far
this project is sweet. thanks for sharing with us.
i think Astro vans were available with AWD back in the day and had a chassis similar to the S-10. i haven't seen one of those vans in forever though.
Yes they were. They're too wide. They are a mash up of 90's full size front suspension, S10 front diff and astro specific axles. The width is the same as full size trucks though and even wider than the TB chassis previously
My BIL has one and I eyed it VERY closely when planning this project
Times 3...or 4? Subbed. This is AWESOME.
I wonder about using a trans "package" that is more integrated than a typical domestic 6 speed + T-Case + Drive shafts +Front chunk (which'll have to sit directly under the oil pan?)
What has a 5 or 6 speed, and AWD in a RWD platform? Audi's...I like that configuration b/c no front drive shafts and the front diff and t-case are all integrated into a single case. BUT, the front axle shafts would be too far rearward in a third gen; all audi puts the axle shafts behind the bell housing flange. Same with Subi's -same layout.
Porsche made a stick-shift Cayenne, that'd be a possible option?
What else? There aren't many stick-shift, car based, RWD based AWD platforms. AWD CTS's? Did they make those w/a stick? (EDIT: No)
I think that one major hurdle, for OEM's and for a builder, is that the front diff and the crank shaft, want to be in the same space, roughly. Otherwise you end up with the engine too high in the chassis, like you saw with the TB SS.
It definitely makes the build complicated
Basically you're doing a 3rd gen body swap onto a small truck chassis?
No, I'm grafting the S10 front suspension to the 3rd gen unibody. It will no longer be a removable chassis
I got a few hours to play with the project today. Decided to prep the S10 frame for fab
First up, possible A-arm option to allow a simple coil over. There's nothing wrong with the S10 A-arm, except the coilover physically cannot fit in the opening
I saw a S10 build that used 2007-13 full size truck A-arms by simply moving the front control arm pocket forward. New A-arms were $60 on amazon. I'm sure the BJ/bushings will be terrible but, I can press good stuff in at the end if they work
What do you know, they bolt on. So, I also got some 12mm SS round stock to keep stuff aligned when I modify the chassis. I decided to measure if they were within reason. They're not
CL of the pivot bushings to the BJ grease fitting on the S10 is 8" like all GM metric A-arms of the 70/80/90's. The full size is 9", so negative camber out of the box. To move the bushing boxes inboard 1", I'd have to pocket the frame and figure out how to get an adjustable bolt in there, UGH
The full size BJ is also 1/4" forward from the S10, so caster is also screwed
So, I get to build my own, nothing is easy it seems. Atleast I can return them
Next up, the chassis was stripped entirely. I shot the brackets to remove with white paint. This is going to take a while
I decided to buzz it with a wire wheel while I was down there. What a mess
Mocked up the empty S10 front diff. While, I won't be using it, I do need to accurately locate the axle shafts
A simple piece of scrap with a hole in it is perfect to align the axle CL
Hopefully this pic shows why I'd rather run a TB front diff than S10. The middle seam is approx the same for both units. The TB unit can fit much tighter to the engine/oil pan than S10, so the engine can possibly be mounted lower. The PS shaft/disconnect housing is a terrible design, so I'm considering a few options to fix/replace it
This is from an AWD astro LS swap I snooped. The fat section of the S10 diff is simply too big around the oil pan. The solution in the van is to raise the engine/trans. That's not something Id like to do on a low slung performance car. The TB diff is far more compact in the same area. I'd like to lower the engine 2-3" from what's seen here
It is a shame you couldn't keep the torsion bar suspension, then adapt the stock 3rd gen strut to the spindle. Clearance and camber for days.
Not sure what the torsion bars would interfere with down the road though. Plus they are so friggin long......
I also think it would be neat if the blazer chassis could act as SFC"s - but at this point you are looking a whole custom chassis. Might as well do a corvette or camaro IRS while you are at it right.
I am just spit balling ideas - I love this kind of stuff. We did a bunch of stuff like this when we did our champ car build. Some ideas worked, some didn't.
Since you're going to S10 front components, could you add a 4th gen rear diff and figure out how to get ABS working?
The electronics to get ABS working are the biggest hurdle, not just wheel speed sensors
It is a shame you couldn't keep the torsion bar suspension, then adapt the stock 3rd gen strut to the spindle. Clearance and camber for days.
Not sure what the torsion bars would interfere with down the road though. Plus they are so friggin long......
I also think it would be neat if the blazer chassis could act as SFC"s - but at this point you are looking a whole custom chassis. Might as well do a corvette or camaro IRS while you are at it right.
I am just spit balling ideas - I love this kind of stuff. We did a bunch of stuff like this when we did our champ car build. Some ideas worked, some didn't.
Torsion bars are still an option. Being limited to the S10 only spring rates and height based on the key location wasn't ideal so I would like to try coil overs instead
To get the bars working, I'd just have to fabricate new mounts for the t-key crossmember
To use a 3rd gen strut, I'd need some sort of hub based spindle. So, FWD based donor
Going that route, I'd use simple 3rd gen coilovers instead or torsion bars
A simple k-member build using S10 lower A-arms may skip the huge chassis graft aspect entirely. I have another junk 3rd gen shell and may try that route on if this chassis fab fails
The S10 chassis conversion will act as SFCs. That part of the build is coming soon
IRS has crossed my mind, but for now I'll stick to a tried and true 8.8. I feel this enormous undertaking is enough for the time being
well all early mopar cars were torsion springs - I wonder if all the bars are the same length. Or can you order spring rates like you can do with moog springs. I have never had a reason to research that.
I do know that most torsion keys are interchangeable and when I wanted to lower my 05 1500hd that it was just a simple key swap for the front. That would've been awesome with the 4 wheel steering.
I didn't consider a fwd spindle, but that is a great idea. I considered a coil over setup like you mentioned, but was concerned about front axle clearance.
could the torsion bar mount double as the torque arm mount should be far enough forward to work well or could that be a reason to do the IRS......
I'm pretty sure that the upper bj for metric G body cars is offset to the rear, so that helps with caster. I have a highly modified 83 Z28 with 2000 Z28 front suspension and rack and pinion. I also moved the front wheels 5" forward for better weight distribution. I can tell you from experience that there is no room for the front differential with the engine in the stock location. You'll have to raise the engine up and/or move it back several inches to make room.
That is the impossible situation that I've never been able to wrap my brain around. People have pursued this on the 'Vette forums too, and simply, the crankshaft and the diff need to both be in the same space. You can have a front diff or you can have a crank shaft, but not both. This is a different car I get that, but with the F-bod, the engine is even further forward, relative to the front wheels, than it is the 'Vette, which IMO only makes the packaging even more difficult.
Looking forward to seeing how this goes. I LOVE the ambition, fab skills, etc.
If you could fit the crank shaft+ damper+ pulley solution, between the rear end of the center console and the center line of the rear axle (which would have to become a Transaxle w/IRS)....then for sure! That'd be a totally cool project with likely, amazing results.
You could put the engine in backward, connect it to a typical 3rd gen trans option, mount a typical t-case on the rear of that, and then use an S-10/GMT400,800.900 front diff, flipped upside down....
You'd also have to flip the rear diff, I guess. PITA. Or get a marine cam, run the engine backward, use the same parts?
The Trailblazers had the front axle shaft pass through the oil pan of the inline 6 engine.
To get the S10 frame/suspension/engine combo to fit in the car and ride at an acceptable height, how much do you think you will have to lower the suspension, compared to stock? I ask because I've kinda been down this road, to some degree and maybe the info will be useful.
Basically what I've got is a very oddball 2004 ZR2 Blazer that is 2wd. It is the very same ZR2 suspension as the 4x4, just missing the front pumpkin and axle shafts. I lowered it about 5 inches in the front, simply by flipping the torsion keys upside down and reinstalling everything as it was. Now, it works, but it's not ideal and I need to make some refinements. For starters, the steering linkage hits the lower control arms quite often while driving. The other thing is the main crossmember under the engine is very close to the ground, like 1.25 in or so (I've never actually measured it) with a 275/40 on a 17" rim.
I'm pretty sure that the upper bj for metric G body cars is offset to the rear, so that helps with caster. I have a highly modified 83 Z28 with 2000 Z28 front suspension and rack and pinion. I also moved the front wheels 5" forward for better weight distribution. I can tell you from experience that there is no room for the front differential with the engine in the stock location. You'll have to raise the engine up and/or move it back several inches to make room.
Agreed, there is no room between the engine and traditional diff
The Trailblazers had the front axle shaft pass through the oil pan of the inline 6 engine.
To get the S10 frame/suspension/engine combo to fit in the car and ride at an acceptable height, how much do you think you will have to lower the suspension, compared to stock? I ask because I've kinda been down this road, to some degree and maybe the info will be useful.
Basically what I've got is a very oddball 2004 ZR2 Blazer that is 2wd. It is the very same ZR2 suspension as the 4x4, just missing the front pumpkin and axle shafts. I lowered it about 5 inches in the front, simply by flipping the torsion keys upside down and reinstalling everything as it was. Now, it works, but it's not ideal and I need to make some refinements. For starters, the steering linkage hits the lower control arms quite often while driving. The other thing is the main crossmember under the engine is very close to the ground, like 1.25 in or so (I've never actually measured it) with a 275/40 on a 17" rim.
I6/V8 trailblazers along with basically any recent AWD vehicle that isn't a truck/SUV passes though the oil pan
Since this is still in the mock-up phase, I'll simply mount it all under a junk hood and lower the S10 chassis section. Lower the suspension after and see if the CV angles are within reason
5" is a huge change for S10s. There may not be a solution if your tie rods are contacting A-arm
Hard to find time these days but I was able to sneak a few hours in to play with the project
The S10 diff was mounted to pull the axle CL. The end plates hold the tube in place with the diff removed
A junk engine was used to mock everything up. This one still had a crank and windage tray to establish max depth. I needed to identify F/R measurements to begin the oil pan modifications
Trans is pretty close to stock height
This is a holley 302-1 oil pan I had from a prev build. My intention was to cut a notch and weld a tube to go through the pan. I could weld diff mount stands to the pan after the CL was determined
The forward and up mark is what the mock-up identified. The bottom is a factory V8 trailblazer pass through CL. The difference is 3/4". I'm not reengineering an oil pan design for 3/4"
I ordered a V8 TB pan to try next. That should allow me to build the motor mounts
Lots of time spent on this only to change directions due to excess complexity and machining. Worth documenting the thought process, however flawed
This is a trailblazer V8 oil pan compared to a normal LS rear sump (302-1 in this case). TB pans are notorious for causing oil starvation issues due to the terrible pickup design. As such I've been keen to avoid them. My goal was to use a tried and true rear sump pan, fabricate a structure to hold the TB front diff on. The solution to the PS axle tube was TBD
A hole transfer plate was made to position the TB diff without the TB oil pan. The mount location was moved forward and up slightly to match the measured CL of the original S10 diff. The goal for keeping that measurement was to maintain S10 CV axle geometry. In hindsight, that location wasn't critical
I added a Fbody LS1 pan and attached simple brackets to emulate two diff mount holes
Trying to avoid some battles with a TBD steering rack, I notched a section of the front diff to clear the S10 drag link. This tab was for 6cyl TBs. All TB diffs have two bolt patterns
Hey it clears!
Tie rod contacts the diff well before full lock. Pretty sure converting to heims will give enough clearance, but detract from the junkyard special feel of this build. Oh well, pretty sure a bump steer kit would be a given on this regardless, so what's a little more on the inner ties
Decided to mock-up my C5 12.8" brake kit and see if it clears the 17" repop GTA wheels. 12mm spacer and they do. Caliper to spoke clearance is about 3/16"
Back to the pan. Transfer plate to position the PS housing on the diff
This was where the sheer amount of work and custom parts really hit me. The diff needs a complex structure to support it and the torsional load it'll exhibit. Using the S10 housing tube, a round plug needs to be turned, pressed into the diff and somehow bonded well enough to keep oil inside at two separate joints. That and it needs to be dead on accurate or the shaft seals will oval and leak. Pretty daunting
Or I could simply use the TB pan, with some mods
I'd cut it in half and the 302-1. Weld the two together and weld a new angled floor in the front so only the rear sump is used. No custom pickup tube, baffle kit or anything. Cutting and fitting can be done with a grinder. The only expected machining is to true up the top pan rail at the joints
The front will need need a notch to clear any kind of steering. It's dead space, so nothing critical
I bought 3 sets of speed engineering long tubes for this build for mix/match or worst case to be used as parts kits. C10, 3rd gen, trailblazer SS
Luckily the trailblazer set fit with small frame notch. That's a huge job checked off the list
The last thing I had time for was the front CV axles
DR side was easy. The TB diff flange was placed in the same location as S10, so the DR axle was stock
PS was more of a challenge as the entire TB diff/ext housing ended up 2" narrower than the S10. That meant custom stuff in the diff or find/make a CV 2" longer. That's where the ZR2 stuff kicked in. I was under the impression that I had a ZR2 frame based on the lower A-arms. After measuring the old CV axles, and comparing them to rockauto, I found they were the normal length. That made the route clear as it would be one LH S10 (regular) CV for the DR, one LH ZR2 for the PS. S10 diffs use a male socket for DR and female for PS where TB are male on both
With the drivetrain located, suspension, axles and exhaust figured out, it's time to mate the two chassis together
Still on the to-do list:
Steering
Least amount of work: notch the pan and use S10 box
Lots of work: either Dodge Intrepid or BMW E46 rack since they have similar travel to the S10 box
lol, well, I guess I won't be the first... my long list of projects will keep me miles behind you, but I bought a Trailblazer 5.3 a while back, and a front diff, with this swap in mind. I'll be following along, nice to see you're still at it.
New CV axles came in. You can clearly see the difference from base S10 vs ZR2. Fits perfect and off the shelf, my kinda find
With that solved, I moved onto building the rocker SFC's that will join the front frame section to the rear of the car. Basic 2 x 4 x .125". I notched the rear section to clear a stiff piece of 16ga sheetmetal. It houses the LCA mount and joins it to the rest of the rear chassis. Seemed important, so I went around it
Basic 1/4" plate for one side of the SFC saddle. I can add the other side/bottom after the fact
Next came hours of leveling the body and frame sections. Once I was satisfied, I tack welded small stubs to join the two frames together and removed to finish join them
If you have to ask someone how to do it, you shouldn't be doing it. I've always said that with enough time, money and fabrication skills, anything can be accomplished and that looks fantastic even if it wasn't going to be AWD.
Have you given any thought to using an LS4? I know the engine would be mounted the other way but if it's AWD who cares. You might be able to literally use all of 1 car and then just scrap the rest. Im pretty sure that would work, even easier. Basically transverse mounted engine.
Edit, they are using a 4T65 Versatrac out of a volvo.
I don't think an LS4 would fit between the frame rails transversely.
Also, any/all AWD configurations HAVE to put the entire engine ahead of the front axle centerline. No way around it. With this packaging, I'd doubt that there is space under the F-bod hood between the axle centerline and the radiator support for the cooling package, steering gear, sway bar...and an engine. I also don't think an engine placed that far forward would fit under that tapered part of the hood.
HOWEVER, the LS4 is a great idea, b/c of it's compact size and "shortness". No reason why you couldn't use it an a longitudinal installation, and that engine would give more room up front for the front diff and associated parts.
I started on the oil pan modification. Take two and make one. Initial rough in's
The BMW E46 rack showed up. I chose this primarily because of overall travel and ratios
3rd gens have around 6.75" of travel. S10 4x4 6.1", BMW 150mm or 5.91". Much closer than the 4th gen 4.5" of travel that people often use
"Good" BMW racks can have a 13:1 ratio, while most base racks like this greaseball get the more common 14.5:1
WS6/IROC boxes had a 12.7:1 vs the base model 14.1:1
Rough mock-up
I'm going to nix the BMW rack on this build for packaging purposes
To make it fit, I'd have to chop out the frame under it, then box it back in
Cut the center hardline port off and move it to the front of the rack
Notch a big C shape into the oil pan
Fab mounts to hang off the rear
Tie rod length and steering shaft orientation aren't major concerns though
What concerns me most is engine R&R. Due to the rear mount arrangement, the rack cannot be taken loose and slid forward to lift the engine strait up. Instead, the engine mounts must be removed. The engine lowered a couple inches rearward and slid forward after clearing the rack. Attach motor mounts last. My concern is firewall clearance in such a maneuver. I do not want to weld the structure together and find the engine no longer clears. Seems important
I may try a Dodge intrepid rack next. The have a 6.5-6.75" travel, but the ratios are 90's econo-car blah. Center take off tie rods may be a challenge to fit into this package too
I will hang onto the BMW rack. I have a feeling it would be a fine upgrade for a more traditional 3rd gen than this monstrosity I've created
Lastly, I bought some cheap amazon S10 lift A-arms. The biggest hurdle for front coilovers are clearing the tiny pocket on factory UCAs. Chop the center metal strip out and bingo
Lift arms also change the balljoint angle and overall length to attempt to correct some camber issues due to being lifted. These aspects may or may not be issues themselves. At $70 it was worth a try
I do need to press a balljoint out and determine a quality replacement. They're not the same as the original S10
02-11-2024, 08:41 PM
