10 bolt non posi to Posi Conversion
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Car: Transam, 85
Engine: 305 HO, 4bbl Carb, G Engine
Transmission: 5 Speed
Axle/Gears: 3.73
10 bolt non posi to Posi Conversion
What is needed to convert a 10 bolt, 7.5", 26 spline axle, non posi .............to a posi. I read some places here, that installing 28 spline to an existing housing need additional welding? Did not understand that part, or might be mixing up with something......
Thanks.
Thanks.
#2
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Re: 10 bolt non posi to Posi Conversion
You need to change the differential. That's about a $400 part. Then since the gear setup depends on the differential, you have to setup the gears again. Setting up used gears is more difficult than setting up new gears. Not really worth putting the money into a 10 bolt.
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Car: 88 T/A, 91 Formula, 94 Firehawk
Engine: 400 Pontiac, 5.0 TPI, 5.7 LT1
Transmission: 700R4, T5, T56
Axle/Gears: 4.10, 3.42, 3.42
Re: 10 bolt non posi to Posi Conversion
Are you keeping the same gear set that is in the existing rear end?
#5
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Re: 10 bolt non posi to Posi Conversion
No. You can't install any ring and pinion other than the 7.5" that the 10 bolt is designed for. And the 9-BOLT Borg Warner is not a 9" ring gear. It's a 7.75" ring gear.
It really isn't worth doing anything to a 10 Bolt. They are just plain weak.
GD
It really isn't worth doing anything to a 10 Bolt. They are just plain weak.
GD
#6
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Re: 10 bolt non posi to Posi Conversion
get a torsen carrier out of a ~99-02 4th gen Z28/TA and install using 90-92 28 spline axles.
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Car: Transam, 85
Engine: 305 HO, 4bbl Carb, G Engine
Transmission: 5 Speed
Axle/Gears: 3.73
Re: 10 bolt non posi to Posi Conversion
A low end posi will do for me. Can I keep the gear (3.73) as is, and change 28 spline axle and a posi carrier?
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#8
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Car: 88 T/A, 91 Formula, 94 Firehawk
Engine: 400 Pontiac, 5.0 TPI, 5.7 LT1
Transmission: 700R4, T5, T56
Axle/Gears: 4.10, 3.42, 3.42
Re: 10 bolt non posi to Posi Conversion
Like 8t2 said the Torsen and a set of 28 spline axles for the 90-92 would be a decent upgrade, but as Drew mentioned 7.5 10 bolt not worth throwing a bunch of money at.
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NoEmissions84TA (01-19-2020)
#9
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Re: 10 bolt non posi to Posi Conversion
Trouble is the learning curve. If you have to ask these questions, and can't find the info without asking, you're not going to be able to find the info to learn how to do the job yourself. The labor, parts, etc are going to preclude it being remotely worth it to gain two wheel peel. When you don't know anything, your best bet is to find a junkyard rear that already has what you want. Otherwise you're going to spend a bunch of money or screw something up.
#10
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Car: 88 T/A, 91 Formula, 94 Firehawk
Engine: 400 Pontiac, 5.0 TPI, 5.7 LT1
Transmission: 700R4, T5, T56
Axle/Gears: 4.10, 3.42, 3.42
Re: 10 bolt non posi to Posi Conversion
Trouble is the learning curve. If you have to ask these questions, and can't find the info without asking, you're not going to be able to find the info to learn how to do the job yourself. The labor, parts, etc are going to preclude it being remotely worth it to gain two wheel peel. When you don't know anything, your best bet is to find a junkyard rear that already has what you want. Otherwise you're going to spend a bunch of money or screw something up.
Case in point. In 1998 I went on a rampage and put a ton of stupid money into my 88 T/A when I was still a dumb 21 year old kid. Hot engine, transmission, headers tune Dart heads whole nine yards. And a mountain of credit card debt to boot 😂 Needing to change out my original 2.77 anemic 305 gears I had a close friend install a 3.73 set and Auburn differential for me. This guy was a good ten years older than me at the time and a hell of an engine builder. Drove the car a week before it let go 100 yards from my house in major fashion after letting out a quick nice whine on decel. Long story short, having a machinist background and tools/know how I tore it apart myself and installed a 4.10 Richmond set after cleaning all the bits and pieces out. Taking my time and paying attention to what I was doing (after previous research) I proceeded to put 20k hard miles on that rear end before I parked it until I started working on it again 12 years later. It’s still in the car and working fine.
If you learn from failures and carry that forward in your endeavors, that is 100% experience gained my friend. Even if it costs you a few dollars. No education is free 👍🏻
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NoEmissions84TA (01-19-2020)
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CKone (01-19-2020)
#12
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Re: 10 bolt non posi to Posi Conversion
Changing the differential will throw off the gear wear pattern. Virtually no one will promise used gears won't whine after a major change. For a home gamer that doesn't understand a 9" ring gear won't fit in a 7.5" housing, you might as well be suggesting they start a space program in the backyard.
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Car: 88 T/A, 91 Formula, 94 Firehawk
Engine: 400 Pontiac, 5.0 TPI, 5.7 LT1
Transmission: 700R4, T5, T56
Axle/Gears: 4.10, 3.42, 3.42
Re: 10 bolt non posi to Posi Conversion
Changing the differential will throw off the gear wear pattern. Virtually no one will promise used gears won't whine after a major change. For a home gamer that doesn't understand a 9" ring gear won't fit in a 7.5" housing, you might as well be suggesting they start a space program in the backyard.
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NoEmissions84TA (01-19-2020)
#14
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Car: 88 T/A, 91 Formula, 94 Firehawk
Engine: 400 Pontiac, 5.0 TPI, 5.7 LT1
Transmission: 700R4, T5, T56
Axle/Gears: 4.10, 3.42, 3.42
Re: 10 bolt non posi to Posi Conversion
How are those harbor freight creeper casters doing btw? Every time I see you post I laugh my nuts off about that lol
#15
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Car: 84 TA orig. 305 LG4 "H" E4ME
Engine: 334 SBC - stroked 305 M4ME Q-Jet
Transmission: upgraded 700R4 3200 stall
Axle/Gears: 10bolt 4.10 Posi w Lakewood TA Bars
Re: 10 bolt non posi to Posi Conversion
If he does not have to touch the pinion at all, not even for a new seal, then all he has to do is get the gear backlash correct.
#16
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Car: Transam, 85
Engine: 305 HO, 4bbl Carb, G Engine
Transmission: 5 Speed
Axle/Gears: 3.73
Re: 10 bolt non posi to Posi Conversion
Appreciate all replies. Thinking of 28 spline axle and a 10 bolt 7.5 posi to the present box. Or buy a 3.27 9 bolt from junk and empty it and build a 3.70. My original one years ago was 3.70 9 bolt disc posi. I estimated a 1.5k would complete entire 9 bolt one. At this point I am making sure all pieces and compatibility between are ok. Once all pieces being sorted out, and their availability, then comes the installation process. Between utube, thirdgen it is available. Only then buying starts.
#17
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Re: 10 bolt non posi to Posi Conversion
Ehhh.... That seems overly simplified. Different carrier means new carrier bearings, and needing to shim the carrier for proper gear mesh and bearing preload. But IDK, I don't do differential work 5 days a week.
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Car: Transam, 85
Engine: 305 HO, 4bbl Carb, G Engine
Transmission: 5 Speed
Axle/Gears: 3.73
Re: 10 bolt non posi to Posi Conversion
JEGS is selling motive gear 7.5" 9 bolt set ($250) and a Detroit truetrac 9 bolt 28 spline posi ($550). Are these two right fit for each other?
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Car: Transam, 85
Engine: 305 HO, 4bbl Carb, G Engine
Transmission: 5 Speed
Axle/Gears: 3.73
Re: 10 bolt non posi to Posi Conversion
A Swedish member name 'keykey' who also did a 3.70 using Australian posi said he did angle grinding on pinion. I had sent a PM but did not get an answer. Any idea what did he grind saying it was hitting the case.
#21
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Car: 84 TA orig. 305 LG4 "H" E4ME
Engine: 334 SBC - stroked 305 M4ME Q-Jet
Transmission: upgraded 700R4 3200 stall
Axle/Gears: 10bolt 4.10 Posi w Lakewood TA Bars
Re: 10 bolt non posi to Posi Conversion
I just recently saw that post. I believe he had to grind the pinion gear teeth because they were hitting the case.
I found the post: https://www.thirdgen.org/forums/tran...rg-warner.html
I found the post: https://www.thirdgen.org/forums/tran...rg-warner.html
#22
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Car: 88 T/A, 91 Formula, 94 Firehawk
Engine: 400 Pontiac, 5.0 TPI, 5.7 LT1
Transmission: 700R4, T5, T56
Axle/Gears: 4.10, 3.42, 3.42
Re: 10 bolt non posi to Posi Conversion
At those prices plus install kit that you will need you’re gonna be near half way to 9” or 12 bolt. May be more cost effective to try and find a complete good used rear axle with the gear you want.
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Car: Transam, 85
Engine: 305 HO, 4bbl Carb, G Engine
Transmission: 5 Speed
Axle/Gears: 3.73
Re: 10 bolt non posi to Posi Conversion
I just recently saw that post. I believe he had to grind the pinion gear teeth because they were hitting the case.
I found the post: https://www.thirdgen.org/forums/tran...rg-warner.html
I found the post: https://www.thirdgen.org/forums/tran...rg-warner.html
#25
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Car: Transam, 85
Engine: 305 HO, 4bbl Carb, G Engine
Transmission: 5 Speed
Axle/Gears: 3.73
Re: 10 bolt non posi to Posi Conversion
While putting the Australian posi did you have to do any kind of grinding to any pinion gear. If motive (or hawks/JEGS) 3.70 ring gear and Australian posi fits together without any grinding, I think that will be the way. Planning to buy a 9 bolt 327 and make it a 3.70 with Austrlain Posi.
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Car: Transam, 85
Engine: 305 HO, 4bbl Carb, G Engine
Transmission: 5 Speed
Axle/Gears: 3.73
Re: 10 bolt non posi to Posi Conversion
I just recently saw that post. I believe he had to grind the pinion gear teeth because they were hitting the case.
I found the post: https://www.thirdgen.org/forums/tran...rg-warner.html
I found the post: https://www.thirdgen.org/forums/tran...rg-warner.html
#27
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Re: 10 bolt non posi to Posi Conversion
teeth grinding. Wow!. ........................my knowledge is definitely on lower end, but I do not understand how a tooth grinding is the way to fix. Specially to high rpm pieces where rotational balance is very crucial and any sort of grinding to the tooth open's up thermodynamic deterioration much quicker then normal deterioration. .....................Any way, I guess it works for him and great................If that be the case I wouldn't build a 370 where grinding is needed....may need to stick with 10 bolt 3.73 or a custom one if I can afford.
There is no way to use the Australian carrier without grinding the Motive 3.70 gear set. So if you are afraid of that then don't do it. Makes no difference to me. I enjoy the heck out of mine and I beat on it hard daily as do plenty of other members.
GD
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Car: Transam, 85
Engine: 305 HO, 4bbl Carb, G Engine
Transmission: 5 Speed
Axle/Gears: 3.73
Re: 10 bolt non posi to Posi Conversion
It's been perfectly fine with the tips of the teeth ground down. There's no contact in that area and the pinion is not of significant diameter that balancing is effected. I removed 1/8" at most off the tips. KeyKey did the same and so have several other users and no one has reported any issues. I've been a mechanic for over 20 years, I'm fairly experienced with machine work, and I'm not ignorant of the engineering principles involved here and I honestly see no issue. There is no load in this area. What do you fear will happen?
There is no way to use the Australian carrier without grinding the Motive 3.70 gear set. So if you are afraid of that then don't do it. Makes no difference to me. I enjoy the heck out of mine and I beat on it hard daily as do plenty of other members.
GD
There is no way to use the Australian carrier without grinding the Motive 3.70 gear set. So if you are afraid of that then don't do it. Makes no difference to me. I enjoy the heck out of mine and I beat on it hard daily as do plenty of other members.
GD
#31
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Re: 10 bolt non posi to Posi Conversion
Yukon sells a duragrip eaton style posi for both 26 and 28 spline axles. When I did mine I ditched my old used 26 spline axles and installed new 28 spline axles in my factory 84 housing.
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