Really in trouble on my GS400 rear

Shakadula51

Member
Hi Bob, That is a $400 to $800 option. I did find a Yukon unit that with bearings and seals would be around $600. This is my last resort if I can’t find the spider gears. I don’t race the car and won’t know the difference between an OPEN diff vs. a POSI.

If you are referring to just the POSI spider/carrier gears, GREAT! I would do that if I could find them.
 
Do an ebay search for Buick 8.2 spider gears. A set came up for $121.45. There may be even better options in that price range. Do a computer search or check Jegs.com, Summitracing.com ect.
They're out there but if your blowing out spider gears you have bigger problems that you need to find. Unless you've been doing donut burnouts and don't know when to quit. In any case you probably have metal shards throughout the axle housing, a full rebuild may be your best bet.
 
The GM part no is 1376754 for the differential pinion gear. That no was used on the '66-67 Buick A-body cars and LeSabre (non-Posi applications). There are a couple up for sale on eBay at:


Also there is pair in stock at:


These are in the range of $15-16. each.

If those leads don't pan out, the 1376754 was superceded by 9783005 in 6/74. The new number shows usage on the '66-67 Olds F-85, '70 Monte Carlo, '67-69 Firebird, and probably others.
 

Shakadula51

Member
Called JD Race and working with him. OLDFONEGUY. I had a so called professional work on my car and he failed to tighten up the ujoint bolts Aafter fixing a rear main seal. I travelled about 100 miles when I was going up hill, heard several clanks that I thought were coming from my brakes and then the car revved with no power being transferred to the wheels. Pulled off the road and put the car in park and it continued to roll. Towed it home and discovered the problem. Of course the so called professional stated he did not cause the problem. Oh, and within a year my rear main seal started leaking again. The professional fixed that too. Told me my crank was bent and that is why the seal started leaking. The crank ain’t bent.
 
Called JD Race and working with him. OLDFONEGUY. I had a so called professional work on my car and he failed to tighten up the ujoint bolts Aafter fixing a rear main seal. I travelled about 100 miles when I was going up hill, heard several clanks that I thought were coming from my brakes and then the car revved with no power being transferred to the wheels. Pulled off the road and put the car in park and it continued to roll. Towed it home and discovered the problem. Of course the so called professional stated he did not cause the problem. Oh, and within a year my rear main seal started leaking again. The professional fixed that too. Told me my crank was bent and that is why the seal started leaking. The crank ain’t bent.
I wasn't passing blame on your problem just a suggestion for the cause. You know it sux that most of us can't do everything on our cars and you have to hand them off to so called professionals for this or that and they screw it up and charge for it. Heck I could have screwed it up myself for free!
Dealing with a situation now myself. Dropped it off at the engine builder for a leaky oil pump he put together. Well he supposedly fixed the leak but I'm still getting drips and now the car won't start! Somehow he messed up the wiring that feeds the coil while cranking. I'm just hoping he didn't melt my wiring with brake cleaner even though I specifically said not to use brake cleaner on the pump because the harness runs right behind it. Heading under today wish me luck.
 

Shakadula51

Member
Jim at JD Race hooked me up with a carrier and spider gears. Should be in the mail today or tomorrow. I sent him pics and he noticed another problem that I didn’t and set me up there too. He also didn’t gouge me on the price. Thanks all for your input. It is a struggle for me to keep this car as stock as possible, hence, wanting to get rid of the skylark rear in it now. That was temporary for 10 years.

oldfoneguy, seems like everytime i have a professional mechanic work on this car, they cut corners and screw something up.
 
I was able to get in depth on the engine today and the distributor gear pin sheared. This is directly related to what he did as he pulled the pump cover to repair the oil leak. The gaskets between the booster plate cover and pump body were leaking from new. That was solved but the distributor drives the pump and it was fine before he took it apart. Now I have to fix that to get it running, great, thanks. At least I didn't get charged for this.
 

Shakadula51

Member
Quick Update: Contacted a rear end specialist and received a carrier with spider gears in it and a rebuild kit. Gave it to my builder and he stated it was a chevy carrier and not a BOP. Chevy screw holes were 3/8 and BOP are 7/16. My blown BOP was 7/16 so not a match. The rear end specialist stated that my BOP must be a 1968 and not a 1967. I believe my BOP is original to my car. Can someone help me figure out the truth. Both of these guys seem to know what they are talking about and I am ignorant on the subject.
 

LARRY70GS

Active member
I know whenever someone asks Jim (jdrace.com) about parts for their rear, he tells them first to verify what they have. We are talking 50 year old car here. You say you believe the rear is original to the car? Unless you have owned the car from new, what basis do you have for that belief? Chevy made an 8.2 as well, a C clip rear. The 68-70 Buick rear was only made for 3 years, and only came in Buicks. The 64-67 BOP rear is a different rear. The BOP rear is well served by the aftermarket. That is not so for the 68-70 Buick Only rear. You need to verify what you actually have in the car. Jim can do that with pictures of the rear cover, rear U -joint retention, and any casting numbers you can find.

www.jdrace.com
 
Your car should have a BOP 10 bolt with the notched sides (image attached). I believe it is specific to the '67/'68 GS400 and is shared with the station wagon. The difference between the GS/station wagon version and the standard BOP 10 bolt being the outer wheel bearings.
At the top of this page you will see a picture of mine from an original GS400:
http://www.buicks.net/shop/reference/posi_102.html

It was a while back, but I believe I installed an Eaton.

Mmmm, my suggestion is a doesn't reflect work with Larry's... He's probably right regarding years, but I will insist the '67 GS400 is shared with the station wagon.

67-diff.png
 
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LARRY70GS

Active member
1968-1970 8.2 is a different rear. Buick only. No ring and pinions produced EXCEPT for the 3.42 and 3.64 sets done by Fabcraft. Auburn has a Posi carrier that works, but even that is relatively new. Parts for the 68-70 8.2 are a lot more expensive and harder to find. The 64-67 BOP 8.2 enjoys wide aftermarket support, you can buy anything for them out of the Jegs and Summit catalog.

TA Performance has the Posi carrier and Maybe (check with them), the gear sets for the 68-70 8.2 10 bolt.


Figure out what you have before looking for parts.
 
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Shakadula51

Member
I returned the gears to JD Race and he refunded my money except the shipping. Totally fair I suppose but the carrier was not correct. I had two different people tell me it was a chevy carrier. I believe in the end he did end up finding the right carrier with 7/16 threads but I had already moved on. Jim at JD Race identified that my carrier was bad; something I didn’t notice. I just wanted spider gears. Between the installer and return shipping I lost $105 and consider it my fault for being so ignorant about differentials so lesson learned. I appreciate the help on this forum.
 

DEXTERS

New member
I blew the spider gears on my 293 10 bolt, 28 spline rear. I cant find replacement spider gears. Can anyone help.
 
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