Flye

I know there are sources for decode of the stampings on the tubes.

I was wondering if there is a source for decode of the cast number on the cast iron center section? (6 digits if I'm not mistaken)

(Trying to see if i've got an Olds rear or Chev. Haven't been able to find the stamped number on tube yet.)

thanks,

d

Oldsmaniac

In 67 Olds used the Pontiac 10 bolt cover rear and also the Olds 12 bolt cover rear. All were bolt in axles. A Chevy rear has a C clip within that holds the axles. I believe the only way your 67 would have a Chevy rear would be if someone swapped it.

wmachine

Try posting a pic from the rear. Our resident rear expert "monzaz" can tell you a lot just by seeing it.
His webpage can tell you a lot: http://www.jdrace.com/

Flye

not an issue on whether it was swapped or not from standpoint of some sort of 'originality' issue. I just want to know if I should be looking for a Chevrolet pinion seal or Oldsmobile pinion seal.

I thought the easiest route was to look at the casting number on the center section 'nose'.

At first I thought it was 8.2 Chev (matching jdrace.com photos), but the 'eyebrow' stamping isn't same in the rear cover.

It is a posi rear.

Any help?




thanks

Flye

same rear end. pinion seal is leaking still. (was just replaced by a shop. going to replace it myself this time, but trying to make sure which rear end this is before I start buying seals...)

don71

I can't help with your identification problem. If your new seal is leaking, chances are you have a groove worn into the pinion yoke. So , if you change it again consider a "speedy sleeve". They come in different sizes, you'll have to do some searching. The link below, show many peaple with the same problem.

http://www.google.com/search?sourcei...ve+pinion+seal

The same thing happens on harmonic dampners at the timing chain cover. They get a groove worn into them and new seal won't stop the leaking. Thats where the sleeve comes in.

wmachine

Contact monzaz with those pics. Either wait for him to come by here, or post your questions and pics on his webpage forum. You *will* get the answers you're looking for.

monzaz

OK, you have a 10 bolt 1971 1972 Olds A-body 8.5 . This rear has bolt in axles. You will need a 2043 8.5 seal ALL 8.5 seals are the same from 1970 -2000. Any parts store will have that in stock.

As stated this is a 1971 1972 ONLY rear. It will fit in all A-body GM cars BUT most except for 1971 1972 skylark...(which came with the same type of rear with a slightly different look, being the rear cover and the traditional 8.5 triangular 5 and 7 o'clock casting id.) This is a stealthy 8.5...lol.

Good luck on the seal swap....CAn be a bit tricky.

TIPS:
1. try to keep the seal area press area of the housing clean and dry.
2. use a sealant on the outer diameter of the seal to keep the gear oil from leaking around the imperfections in the housing seat area.
3. find a deep larger diameter socket to tap the pinion seal equally into the housing...some times a exhaust pipe can be used...going around the side by side tapping could get frustrating and you will end up twisting and deforming the seal.
4. be careful not to jar the spring from the inside of the seal lip ...this will cause instant failure also. packing grease can help keep this spring put from popping off upon hammering in the seal to the housing snout.
5. GREASE or oil seal lips well or again seal will fail quick.
6. inspect yoke for wear.
7. do not over tighten the yoke nut and crush the bearings too much into the races...your bearings will over heat and fail.
8. Last stake the pinion nut with a pointed punch where the nut meets the thread in at least 2 spots...this will prevent the nut from backing out. DO NOT OVER TIGHTEN THE PINION NUT!!!! this will crush the crush sleeve too far and burn the bearings up.

Good luck and I am always at jdrace.com to help with differential questions.

JIm

monzaz

I am working on keeping track of casting codes as I run into new ones. What is the one on your diff? Jim

Flye

maybe that is first reason that it is still leaking. guy that replaced it said it was a Chebby.....

Thanks for your great help. I'll get the casting.

Flye

407296 is what I'd say is in the 95% probability. (with outside chance that either of the two last two digits were 8)

monzaz

Yes we have thaT SAME PROBLEM...LOL. tHAT IS WHY THEY HAVE THE 1234567890 CASTING TEST RUNS ON THE CASTING SO YOU CAN COMPARE... rEALLY THAT IS WHAT IT IS FOR. jIM

Oops sorry for the caps...I have to watch the keys as i type. LOL. Jim

Flye

replaced the pinion seal yesterday morning. same mfr., but definitely different style seal comparing the one that was stated to be correct above and what came out of it.

haven't seen a leak yet, but also haven't driven it yet. did as instructed on tightening pinion bolt, and it turns fine.

replaced the rear gasket and cleaned up the cover while I was at it.

thanks for help. even if I didn't do it right, it isn't going to be any worse than it was from the 'repair shop'.

p.s.: yoke was fine, non grooved.

sklbndt

Hey Flye,
Sorry things didn't seem to work out at the shop I recommended. I certainly hope you didn't just say the heck with it and give him a pass.
Anyhow, it looks like you got some great info on here. This place is an invaluable source of information.

monzaz

Did you stake the pinion nut? Please do. Jim

jensenracing77

i just picked up three 69 cutlasses and one had the rear end changed. the cover looks just like this one. the code that i am use to seeing is not there. is it in a differant location on these axles? i normaly see them on the right back side of the axle tube on an O type.

monzaz

Well I am believing more and more that the LATE 1970 cutlass and Skylarks started to receive the 10 bolt 8.5 early. That may be an original rear to that 1970 car. try the passenger side front of the tube or driver side front of the tube and see if is there. Jim

Flye

Just a brief note that I've put a few miles on it, and so far, no leak. Nice and Dry.... (One of the few things under there that isn't leaking!!!! One down, 4-5 to go....)

Thanks for all the help on the seal number!!!!!

D

monzaz

8) Jim

Great Job.

drewt

I've been reading this thread because I've got to replace my pinion seal. Where can you find these Speedy Sleeves? Also, one of the replies mentioned staking the nut. Not sure what this means. Would that prevent removal later on?
I've also been trying to identify my diff in a 70 Cutlass Supreme 350. What is the most common? Can't seem to match it up with what I've found on the internet.

507OLDS

They installed the 12-bolt O-axle all the way to the end of production.I've owned some 70's that were built the very last days,& they still had the 12-bolt O-axle. I've also talked with people that actually worked on the line to confirm that.The stamped codes on the 12-bolt O-axle will be on the passenger side tube,facing the back.They were upside-down for 67-69 because the assembled the chassis that way.The codes are right-side-up for 70,but still in the same location.

As for the 8.5" 10-bolt ID stuff. Every 71-72 Cutlass/442 that was built in Lansing came with the "O" casting,meaning it has a large letter "O" on each side of the pumpkin,where the tube goes in(frontside). All of the other plants mainly used the "A" casting which has a large "A" on the top of the pumpkin,& one on each side. The "O" casting has the round cover,with the protruding rib from 12:00 to 3:00. The "A" casting has the smooth cover with the notches at 9:00 & 3:00.These covers look just like the BOP 8.2" covers,but are slightly taller.
All of the 71-72 Buick Skylarks/GS cars that I have ever seen have the "A" casting 10-bolt.
All of the stamped codes for the 8.5" 10-bolts are on the passenger side axle tube,facing the front.