fredsolds62

I have a 1962 Super 88 with 57,000 miles. It sat in a garage from 1966 until I purchased it in 2020. The differential driveshaft seal is leaking quite a bit so I would like to replace the oil and the seal at the same time. The manual says "GM Special Lubricant, part no. 531536 but I can't find what the the generic equivalent would be. I'm guessing that 80/90 weight gear oil would be a good substitute but I want to make sure. Any help would be appreciated.

Charlie Jones

There is no drain on the rear axle.
Most of the gear lube in that axle may be 60 years old.
In order to change this oil the axles and the diff carrier must be removed from the axle housing.
Clean everything with mineral spirits.
Re-assemble with new gaskets.
Refill with any GL-4 or GL-5 80W-90 gear oil.
If this is a posi unit a half pint of posi additive must be added first.

fredsolds62

Thanks for the reply and advice.
I removed the seal and bearing and let it drain until it stopped. Then I put the rear end up on the tall jack stands and removed the front wheels to make more of an angle. It drained quite a bit more oil out at that point. Do you still recommend pulling the axles and carrier? Or is the reasoning that there will still be a lot of oil stuck to the internal gears and housing and only mineral spirits will get it all out?

Charlie Jones

I guess it depends on what the stuff you drained out looks like .
Is it nice clean looking oil?
Or does it look sludgy and dirty?
If it does, then yes. Clean it thoroughly.

fredsolds62

The oil was black but no sludge or debris and no particles using a magnet in the oil so I'm going to fill it with new oil and drive it. Maybe in a year or so I'll drain and refill it again.

I've been working on this car for over 3 years. I replaced or rebuilt everything in the braking system, fuel system, cooling system, suspension system, new tires, painted the wheels, and buffed and polished the paint. The seats had clear plastic covers so they are like new. Unfortunately, the headliner has disintegrated so that will be replaced next. The engine turns over freely but I have not tried to start it yet but hope to do so in the next few weeks.

Thank you for your help.

Oldsguy

Could you put someting in it to flush it out? Maybe some kerosene or deisel, the lower viscosity stuff might help flush it and clean it too.

fredsolds62

Good idea. I'll try with some diesel.

Charlie Jones

Be careful.
Putting diesel, mineral spirits, etc. will thin the oil out since you can't drain all the oil out.
When you put the seal back in, and fill the diff there may be as much as a pint of diesel and dirty oil in there already.
This would thin the new oil out, and it may not provide proper lubrication.
Leading to gear or bearing failure.

Better to drain it as best you can, and then fill with fresh oil.

monzaz

I have to agree with Charlie on this one. - Complete removal if it needs to be cleaned with kerosene mineral spirits etc. These fluids will thin out the oil and when you add the new oil it will be too thin and NOT protect from the heat the gears create.

SO.
either just drain the old oil best you can and fill it with new fresh oil to proper fill hole drive it and drain again and again till it is all clean...- Not a great way to do things...BUT if that is all you can do at this point...well. do it I guess.
best way is to inspect everything with a total disassemble and it will be WAY easier to install the NEW seal also and make sure you do not do that job wrong from over tightening the pinion NUT.
Jim
JD Race

fredsolds62

After giving it some more thought, you guys are right. So, last night I pulled the axles and started to remove the front of the differential housing so it could be draining all night. Searching for a gasket set today and hope to work on it later this week. Thanks again for the advice.

Charlie Jones

Gaskets are available thru O'Reilly's or Rock Auto

fredsolds62

I ordered the differential housing gasket and the dust shield gasket from O'Reilly's today but they told me that the axle to backing plate gasket was not available. I'll try Rock Auto right now.
The old car hobby has some of the best people in the world. You guys have saved me a lot of time and frustration. I can't say it enough, THANK YOU.

Charlie Jones

No matter what it is, there's always somebody who has "been there and done that" . And is glad to help the next guy.

fredsolds62

Well, life got in the way of my hobby so over a month later I'm starting back to work on the differential. I got all the gaskets and put it back together but when I turn the companion flange it is not smooth. It's jerky and very hard to turn in some spots. I'm guessing that when I replaced the pinion seal and put it back together I damaged the pinion gear crush washer? Either that or the bearing is bad? I have not pulled the carrier out yet. Looking at the manual and the procedure it looks pretty straight forward but I would love to get your advice first. Where can I buy a crush washer?

Sugar Bear

is the driveshaft connected? If yes, disconnect it and retest. If not smooth with driveshaft disconnected, leave it disconnected and try it with the brake drums off, then with one axle out and then the other one. Hopefully it is a brake issue. You could pull the drums first vs the driveshaft, your call.

fredsolds62

I removed the entire carrier assembly from the housing, and it is sitting on my workbench in a holding jig that I made. It is definitely something in the pinion and/or ring gear. The car sat in a semi climate controlled garage from 1966 when the original owner passed away until I purchased it in 2020 hence the low mileage of 57,000. I have read and studied the manual but I have never taken a differential apart before so I'm being very cautious. I suspect the pinion crush washer is bad and maybe the pinion gear. The manual talks about instances when the crush washer should be replaced and since I removed the pinion nut to replace the seal I think a new washer will have to be installed.
The mistake I made was not turning the companion flange before I removed the pinion nut and seal so it could have been this way before I removed it. Even though I torque the nut to 10 - 15 inch pounds, it is still binding.
I would feel a lot better if I could find a new crush washer.

Sugar Bear

Searched on 1962 Olds crush sleeve and had many results. At 57K miles it should be ok.

Are you saying the nut was tightened to 10-15 inch lbs. or the nut was tightened until it took 10-15 inch lbs. of torque to turn the pinion shaft?

fredsolds62

After I replaced the pinion seal and the pinion nut only hand tight I slowly turned the companion flange and it was jerky and tight in spots. Per the manual I slowly turned the flange while tightening the nut to a maximum of 15 inch pounds and it is still tight in some spots.
Last night I removed the carrier assembly from the housing, marked the bearings and caps per the manual. The pinion outer bearing seems to turn freely but I don't know what to look for on the crush sleeve to know if has to be replaced.

Charlie Jones

Contact "Monzaz" on this forum.
He has a shop specializing in differentials, and can give you good advice.
He may also have crush sleeves and any other parts you may need.
ClassicOldsmobile.com - View Profile: monzaz

Sugar Bear

^^^Great advice^^^