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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......
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.
If I use the existing one as shell, can I install a 9" ring gear ?
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.
get a torsen carrier out of a ~99-02 4th gen Z28/TA and install using 90-92 28 spline axles.
This is probably your best bet unless you can source a good 26 spline differential. If the gears are already installed and in good shape changing just the carrier is not a bad deal. Just need to reinstall with the ring gear in the same position side to side as it was with the open carrier by shimming as necessary. Hell if you have drum brakes you might not even need to take the wheels off.
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.
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.
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.
To me the fun from two wheel spin and traction gain is worth the $300 give or take he might spend to do the swap. $300 for fun factor I’m not opposed to that one bit. If he has an existing gear set in housing already and only needs to swap the carrier that’s pretty straightforward imho. When you get into setting pinion depth, crush sleeves and back lash that’s a different animal. Bottom line is do your research and get to the point of feeling comfortable doing it and go for it. No one ever learned anything by not taking a chance 🤷🏻♂️
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 👍🏻
Better off starting with a used 9 Bolt with disc's. Torsen from Australia, 3.70 Motive gears, and a rebuild kit. I have a thread with all the part numbers, etc.
To me the fun from two wheel spin and traction gain is worth the $300 give or take he might spend to do the swap.
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.
Better off starting with a used 9 Bolt with disc's. Torsen from Australia, 3.70 Motive gears, and a rebuild kit. I have a thread with all the part numbers, etc.
GD
There’s a guy with one here for sale near me a couple hours away that if we get a few weeks out and he still has it I’m going to pick up. A torquey 400 Pontiac with a 700r4 and 4.10 gears is nothing but a tire liquidation event 😂
Originally Posted by Drew
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.
I’m willing to bet this is a 30 plus year old differential where the wear pattern has more than be established. If he installs the differential and ring gear in the exact spot it was placed with the open differential I don’t see a problem whatsoever. Idk if it’s a 16 yo kid or a 40 yo man the OP is but regardless, he’s gonna learn today. If he’s a got a stock to average power plant and has half an ounce of common sense it’s doable. Wondering if a 9” gear will fit the 7.5” housing? Well that’s a whole other thread brother lol
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.
How are those harbor freight creeper casters doing btw? Every time I see you post I laugh my nuts off about that lol
Still in a box. They'll come in handy some day... They'd probably make a better creeper if I just bolted them to a slab of plywood.
Originally Posted by NoEmissions84TA
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.
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.
Better off starting with a used 9 Bolt with disc's. Torsen from Australia, 3.70 Motive gears, and a rebuild kit. I have a thread with all the part numbers, etc.
GD
JEGS sales 3.70 gear set and 9 bolt posi of 28 splines. Are they right fit?
Better off starting with a used 9 Bolt with disc's. Torsen from Australia, 3.70 Motive gears, and a rebuild kit. I have a thread with all the part numbers, etc.
GD
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.
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?
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.
The JEGS unit is for the GTO rear ends. It doesn't fit the F body 9 Bolt. You need the one from Australia for the Holden Commodore VE. The exchange rate is very favorable right now - US Dollar is worth $1.45 in Australia.
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.
The JEGS unit is for the GTO rear ends. It doesn't fit the F body 9 Bolt. You need the one from Australia for the Holden Commodore VE. The exchange rate is very favorable right now - US Dollar is worth $1.45 in Australia.
GD
Sir,
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.
I read the PM and did not understand how can you change gear ratio of 3.73 to 4.11. Surely anything is possible, but for a regular drive car, gear ratio be changed like that? Wouldn't that mess up MPH and proper power transfer in drive train. 3.70 to 3.73 is insignificant, but 3.7 to 4.11 is too much for daily drive .............I think.
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.
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.
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
Understood, and thanks for the explanation. Do you happened to have a photo of pre and after on the pinion gear at least to get an idea how it should look if work needs to be done on it.
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.
