88iroc86z

I have an 86 camaro that has the gm 10bolt 7.5 rear differential. I want to put in a posi rear axle and lower than stock gears. Can I just swap out the guts from another differential that is posi or do I need a whole differential axles and all? Oh and I am planning on 350-400HP/TQ when the build is complete.

Johnny Blaze

iTrader: (15)

If you have the tools and knowhow to set up a ring and pinion, yes posi and gears can be swaped.
If you don't have the tools swap the whole rear end.

AlkyIROC

yes and no

You have a 2.73 diff. That means it's a 2 series carrier and the 88 will have 26 spline axles.

If you wanted something like 3.73 junkyard gears, those are for a 3 series carrier so they won't fit on your carrier. If you found gears with a posi then you could swap them directly over into your diff unless they came from a 90 or newer 7.5 10 bolt. Those would need 28 spline axles for the posi. Only 90-92 third gen axles will fit into 82-92 third gens as long as you used a carrier for 28 splines.

If you want to swap to a deeper gear, you could buy thicker gears in the deeper ratio that are designed for your 2 series carrier. If you want a new posi, just buy one to match the gear series you intend to buy.

If you found a junkyard posi, you would need to know what series gears it's designed for then buy gears that will fit it.

Don't invest a whole lot of money into the 10 bolt. Even stock powered cars can break the gears. No matter how much you try to beef it up, you'll still have the tiny ring and pinion teeth.

Ron U.S.M.C.

Swapping in a complete rear end from another car that has the gears that you want and hopefully having a LSD (posi) that works is an option that many have used. Less expensive and if the thing blows up on you you can always find another
or
you can try building a 10 bolt with new parts and a support cover similar to this one =
https://www.thirdgen.org/forums/tran...de-photos.html
or
you can buy a 9" or 12 bolt rear end that has been altered to bolt directly to a Third Gen. Camaro/Firebird that although is the most expensive option you will not break them. (Best investment if you’re going to be using slicks/drag tires and launching hard.) I would read the post in the link I provided and take a hard look at this sticky
=
https://www.thirdgen.org/forums/tran...-10-bolts.html

I have read somewhere on this site this statement =
If you can spend good money building an engine you will also need to spend some money on a rear end that can handle it. They are a package deal. One directly supports the other.

88iroc86z

AlkyIroc: can't I just swap the carrier out as long as the axle is still another 10 bolt 7.5

Ron : You are definitely right. I do plan on buying a 9" or 12 bolt that has been modified. However I want to drive it while I'm saving for it as it will be a lump sum all at once.


My thoughts were to slide the axles out then take everything else inside....

big gear head

Read the sticky FAQ about 10 bolts. There is a lot that you need to learn and most of it is in that sticky. Changing rear end parts is not like swapping a cam or something simple like that. It takes special skills and knowledge.

AlkyIROC

The carrier (posi, open, gov lock etc) comes in different series or sizes. Most common for the 7.5" is 2 and 3 series. Really deep gears in a 12 bolt use a 4 series. Ford 9" has no series. Buy a posi for it and use any gear ratio available.

You have a 2 series carrier. If you find a used 7.5" 10 bolt posi from a 82-89 GM vehicle, it will bolt right in however even the posi came in 2 and 3 series. Depending which gear ratio you want to use, you need the proper gear set to install on the posi. You can't install a 3 series gear set onto a 2 series carrier.

If you find a 90+ 10 bolt posi, it will physically fit in your diff but you will need to find 90-92 third gen 28 spline axles or aftermarket axles.

Now before you go looking through the junkyard for a posi, also think of this. Factory posi's were not all that great plus you're looking for a 25-35 year old posi that's probably going to be worn out unless it's a low mileage wreck that's been sitting around for decades. In the long run, it's better to buy new.

Johnny Blaze

iTrader: (15)

You must have missed what I said.

Do you have the tools to properly set and measure pinion depth, backlash, and know how to read the contact patch?

Setting up a ring and pinion is not like changing the oil. It takes some specialty tools ( at least $200 worth of tools) and a lot of work. Assemble, measure, remove, add a shim, reassemble, remeasure, etc....

Most shops in my area charge a minimum of $300 in labor alone, if you bring them thr axles out of the car.

Not too mention the fact that you are dealing with used parts.

Read alky's response again as well. Lots of good info.

My suggestion would bd to look for a 9 bolt and swapthe whole thing. Or if you are planning for more power, just save the cash and wait till you can afford a 9".

88iroc86z

Thanks everyone for the answers. Sorry I missed the above stickied posts in other threads.

Johnny Blaze.... I thought I had all the right tools at my dads but turns out they are not the "correct" tools and they are the "a friend did it this way" kind of tools. Thanks again for all of the help.

I will be returning to this message and the above mentioned threads for further assistance.

mjw2993

i have a 88 camaro with a 10 bolt rear end and the pin that holds the axle in place is stuck any suggestions on how to get it out? The bolt that holds the pin in place came out easy and is not broken.

AlkyIROC

If all of the retaining bolt came out, the center pin should just slide out. Give it a tap with a hammer and a punch. You're not going to hurt it.

big gear head

If you have been doing a bunch of one wheel burnouts then you may have welded one of the pinion gears to the shaft. I've seen this several times. One wheel burnouts are a big NO NO.

mjw2993

The hammer thing didnt work i hammered on it for around 3 hours and the pin comes out about a 1/4" and stops. I have limited money and need to find a new rear end if i cant get it out.

big gear head

Have you been doing one wheel burnouts?

mjw2993

i have had the car since i was 16. yes i have done burnouts. Is the pin suppose to spin?

midias

Post a pic

big gear head

The shaft is not suppose to spin when the retaining bolt is in it. With the bolt out the shaft will spin. If you have the bolt out and the shaft is spinning but won't come out then you have welded one of the gears to the shaft. You may need to cut the center out of the shaft so you can remove the axles to get the differential out.

mjw2993

I seen that the bolt was broken off in the pin along with in the housing on the other side. It has worn a groove in the pin from the pin spinning. Cant post pic right now I am at work. Looks like its been like that for a while. the differential was messed with before I got the car.

mjw2993

If I was to swap out my rear end from a 10 bolt drum brake to a 12 bolt disc. What all would i have to swap out? i know i have to take one of the valves out of the master cylinder but which one? And what gear ratio should I go with in the 12 bolt, I have a remanufactured 350 and a rebuilt 700R4 trans with a shift kit.

big gear head

I'm assuming that you mean an after market 12 bolt because there are no OEM 12 bolt rear ends that fit these cars.

The gear ratio will depend on what type of driving you want to do. A 3.42 works well with the 700 for every day driving with pretty good performance. You will probably have to modify the drive shaft a little to work with the 12 bolt, unless you can get it built with the 3R yoke. I have done that, but most of the companies who build these rear ends don't.

mjw2993

yea what year camaro's can i use the rear end out of? without having to changed the rims.

mjw2993

(10 bolt rear ends)

Johnny Blaze

iTrader: (15)

any 82-92 camaro or firebird rear

big gear head

'90 to '92 is best because of the 28 spline axles, although you can put 28 spline axles in any of them as long as you also install a 28 spline differential.

mjw2993

thnx im getting a 10 bolt from hawks third gen in easly, sc (posi trac, 28 spline)