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stealthbob

Rear Diff oil change

12 posts in this topic

Ok so when I first got this car I checked the rear for trans fluid contamination and found nothing..only a thick oil.

After years of sitting I am now going through everything properly to put this car on the road and into regular service, I drained the oil out of the diff and got a very thick black result which I believe is a good thing.

 

My "might as wells" tells me to open everything up and flush clean and restore, new me says ask (and listen to) the ones that know better.

 

Do I simply just refill the diff fluid with 90wt and be done?

 

Note that I have zero indication of any issues, from the little road time this car had I did not have any rear end problems or noises.

41356556172_71999489f7_o.jpg

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I would pull the cover for a good cleaning with brake cleaner and get all the sediment out of the bottom of the housing.  It is not hard to make a gasket, or order one from Bob's Automobilia.  You are lucky to see thick oil.  Light, reddish oil is very bad news.  It would indicate trans fluid has thinned the oil and caused wear to the ring and pinion...

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I would measure the quantity of gear oil you're getting out of it before you toss it and compare it with the OE specs. If the rear wheel seals along with the gasketed areas fore and aft of the axle housing's center point don't show any signs of leakage, everything appears to be sealed up tight. It would be interesting to know whether you have the later-1954 style rear axle housing (my guess). Thanx.  

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Bob,  mine was similar.   Dark, thick and stank the high heavens.  As Doug stated, pull the cover.  Clean it out.  Cut a gasket(that is what I did. )  Fill with 90W hypoid gear oil.   I believe I used Valvoline.       I did the service 5000 or so miles ago.   No issues.  

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Perfect...all good news then! Looks like an easy job to do as well.

 

Thanks lads, not used to seeing oil like that.

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2 minutes ago, stealthbob said:

Perfect...all good news then! Looks like an easy job to do as well.

 

Thanks lads, not used to seeing oil like that.

 

The worst part of the job is the God awful smell of diff oil.   Old or new!   

wndsofchng06 likes this

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Straight 90 should serve you well.  I use 85w-140 and the rear is less noisy when hot.  I use it too in the transmission of my 51 F-1 and can actually shift the gears without warmup when cold.

Avgwarhawk likes this

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4 hours ago, old-tank said:

Straight 90 should serve you well.  I use 85w-140 and the rear is less noisy when hot.  I use it too in the transmission of my 51 F-1 and can actually shift the gears without warmup when cold.

Well considering my climate 85w-140 may be the better route.

 

 

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Yea no doubt, the smell alone made me think I better plan this one.

I have the cover off and a thought came to mind. You know when your going through an old Buick and you keep coming across issues, mods or botched repairs. I see it all the time on the forums. I am reminded time after time when working on this car that I have a real clean Buick here. The gear teeth are perfect, the witness marks centered and true.

I should not be surprised...this is after all a Harriet Wilkinson's car of Wilkinson Buick in Utah.  A one owner car that was in a Buick dealership family and only has 48k miles on it. 

MrEarl likes this

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Just cause everyone likes looking at rear ends :)

 

Gasket cutter work tomorrow

41398714682_58bd7be2bb_o (1).jpg

 

A nice old vid for explaining the differential...I used this with my boy to teach him on what we were working on.

 

 

Father Buick, 72gs455 and old-tank like this

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