foo

Im trying to figure out what rear end i have, I found some numbers if they help..

monzaz

That is a Pontiac Hi Performance Nodular rear found in GTO's

If it has all the guts it shoukld be a keeper.

Only thing I worry is the posi is whooped. Gonna have to pull it and disassemble it to see if the cones are bottomed out and rubbing preventing the posi from gripping the conical surface of the unit.

If you can find the axle tube suffix code XH or something like that Should be on the driver side rear of axle tube facing back of the car. Between the spring perch bracket and the cast center section the tube is pressed into. Jim

JD

foo

Thank you. I will have to check everything out, I didn't want to do anything to it until i found out what it was.

foo

It looks to be "259 XM" top of the "X" is worn off.

foo

so to be clear is it safe to say a 70 pontiac gto rear end?

monzaz

I would say yes. Jim

foo

These are for you Jim

monzaz

1969 gear month 9 (sept)
9 teeth on the pinion
39 teeth on the ring
4.33 gears
looks to be XM code to me also.
4 pinion posi unit

foo

Any recommendation for places to get a Bearing and seal kit for this

monzaz

85.00 for the Pontiac rebuild kit axle bearing and seal kit 69.00 (does both axles) BUT need to know the axle bearing type you have sealed (RW507CR 8594S) or oiled (A9 2146 seal)

Jim
JD

foo

are oiled the ones that you are able to openly see the bearing rollers?

foo

Some pics

monzaz

Yes that is a Oiled Axle Bearing. The seal is on the axle outboard the bearing.

A sealed bearing will have the seal in the axle tube inboard of the bearing between the oiled center and the sealed bearing that get no oil. Jim

That rear must be at least 1969 1970 1971 1972

Jim
JD

foo

So that being said are prices still the same and where might I get them?

Another question; When they talk about sizes of differentials ex. (GM8.5/8.625, GM 8.875 in etc..) is that the diameter of the ring gear from outside to outside or inside to inside?

Some bad new is that I got the pinion out and its got a chip in on one of the teeth

Run to Rund

Depends on where the chip is. . .might not matter. If you can take the rear to monzaz or 507olds, you could be money ahead. There aren't many of those diffs left, especially in performance ratios like yours. You wouldn't want to learn and have a failure while learning on that rear.

droldsmorland

Find your bearings at your local (or close) BDI Bearing Distributor Inc. Google it for the nearest one. They ship. Get the numbers off of everything before you press or chisel them off. Be sure to ask for USA made parts they will have choices.

monzaz

Yes the 8.5 8.2 etc is the OUTER diameter of the gear measured across the center outside to most outside.

Chip... Send pictures from different distances so we can evaluate the chip damage.

Axles bearing through me are the same price sealed or oiled with correct axle seal included....we buy them by the gross...lol. Jim

foo

The chip

Run to Rund

Looks like the chip goes into the drive side wear area, definitely not ideal especially for racing.

monzaz

Yep, Could be an issue. Only way for sure is to take a grinder and clean the chip of the sharp edges and reinstall ...see how it feels Tough call. Jim

foo

Crap not what I wanted to hear,

otherwise Im gonna have to change out both gears?

monzaz

Just clean it up and be honest with the rear when selling. Some one may want it for a Show type car and not need to DRAG race the thing. In sight it is NOT going to just fail or bind. Just not a gear you would trust to hard acceleration passes on a sticky track. LOOKS like you just chipped it too? It is fresh ...Really it may still run just fine. Jim

I have given you the pattern run line you can see how close that is.

foo

I sent you a PM monzaz

foo

one other question is this 8.5, 8.2 or other ring gear only measures 8in?

droldsmorland

FYI the ring gear measurement is the ID of the gear not the OD.