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1956 Buick differential lube


Airy Cat
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The 1956 Shop manual for the 1956 Buick states that the 90W factory lubrication in the rear axel  must not be removed or replaced. 

So, I am wondering if that original 61 year old factory lube is still good?  There is no way to drain it.

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I suspect that means "in normal service".  In those earlier times, and probably some more recent, too, many people changed all of the original fluids after a few thousand miles.  Allegedly to get all of the machining "remnants" out of the oil and fresh new grease.  Not unlike changing the factory motor oil at 1000 miles rather than at the regular oil change interval.  After several decades "in the housing", it's probably time.  Reason is the accumulation of moisture from temperature variations.  Even with "low miles", unless that moisture gets cooked out periodically OR the oil changed, non-desirable things can happen.

 

Many modern automatic transmissions don't have a recommended maintenance interval for fluid changes "in normal use", but outside of those parameters, there is a mileage spec for fluid changes.

 

NTX5467

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12 hours ago, Airy Cat said:

The 1956 Shop manual for the 1956 Buick states that the 90W factory lubrication in the rear axel  must not be removed or replaced. 

So, I am wondering if that original 61 year old factory lube is still good?  There is no way to drain it.

 

I don't believe the writers of the manual were thinking 60 years from date of manufacture.   I changed the fluid in my 54.  Smelled the high Heavens. Replaced with 90w gear lube.  Works fine.   

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The 56 rear axle can be drained by removing the lowest bolt on the face of the carrier ( not the back of the rear axle, but the side with the torque tube).  However, I am on the fence about the need to drain and replace this lube.

 

Unless you could remove a cover to get inside and clean out any accumulated debris, what's the point?  If I had the torque tube/axle assembly out of the car then I might think about opening it up for inspection and cleaning and new fluid. Otherwise, I would just check the level and top it off. 

 

 

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2 minutes ago, avgwarhawk said:

 

I don't believe the writers of the manual were thinking 60 years from date of manufacture.   I changed the fluid in my 54.  Smelled the high Heavens. Replaced with 90w gear lube.  Works fine.   

 

I agree with Chris about the manual writers failure to plan 60 plus years ahead,  but smell of this lube is not an indicator that it has gone bad.  I still have some 90 wt I purchased in the 70's and I recall that it smelled pretty bad back then.  If it smells the same today I think it's okay.

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2 minutes ago, JohnD1956 said:

 

I agree with Chris about the manual writers failure to plan 60 plus years ahead,  but smell of this lube is not an indicator that it has gone bad.  I still have some 90 wt I purchased in the 70's and I recall that it smelled pretty bad back then.  If it smells the same today I think it's okay.

 

The smell was just an observation of mine.   They all smell.  I understand the old whale oil was worse yet!     

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12 hours ago, billorn said:

 

This thread has some good information but it looks like it kind of went off the rails at the end. Ignore that and it will probably be helpful.

 

It didn't "go off the rails at the end" I just stopped dealing with it. The information is good--just make sure you put the rear end cover back on correctly. Someone in the distant past had put it on wrong and I didn't notice and put it back on incorrectly, then over-filled it. Caused a few headaches but shouldn't have been a big deal (shouldn't have been being the key). I used 140 weight gear oil found at O'Reilly's Auto Parts which seems to be a good choice and is GL4 for older cars. The real problem and the thing that pissed me off was that some of the other posters goaded me into taking the whole rear end apart looking for a problem where there wasn't one. 100% my fault for listening, but I accidentally dropped one of the main bearing caps, which, of course, was covered with slippery oil. It hit the ground and the mounting ear broke off. So now my Limited is an expensive piece of garage art until I can find another main bearing cap. Sadly, the rear ends on these cars are unique to the '41-42 Limiteds, so my chances of finding another one are on par with finding a leprechaun to grant me a wish for a new main bearing cap. Went to change the oil, ended up sidelining my car for the indefinite future. It should have cost me $25 to put some fresh oil in there, but instead I'm stuck with a broken, unusable car that needs expensive unobtainium to be operational again.

 

So just change the oil. Don't let anyone else tell you about "while you're in there" nonsense. If it ain't broke, don't fix it.

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3 hours ago, JohnD1956 said:

The 56 rear axle can be drained by removing the lowest bolt on the face of the carrier ( not the back of the rear axle, but the side with the torque tube). 

 

WHAT. Ive been using a hand pump to siphon the old oil out of the fill hole this entire time...

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Just now, JohnD1956 said:

 

How many times did you do this?

 

3 times. The first time when I started working on the car, the second time when I swapped my beat up carrier for a good working one, and the third time right before I left for the university... and I might also add, I could have skipped dropping the straw and breaking a four finger grabber inside the differential the third time... got everything out, though.

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Somewhere I have the letter I received when I inquired about my '60 Electra in 2010.

 

It started something like "We appreciate your purchase of the new Buick and find it regrettable that, in 50 years, you have not attained the wherewithal to purchase another of our fine vehicles."

 

There are details, but not promising.

Bernie

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4 hours ago, Beemon said:

Ive been using a hand pump to siphon the old oil out of the fill hole this entire time...

 

Which certainly beats pulling the carrier when that's the other choice.  The concern is that siphoning the old fluid doesn't really clean anything out -- and after 50 years, there could be all manner of flakes and goo inside.  If you can drain through the bottom bolt, at least you've got a fighting chance of flushing some of that stuff out.

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Siphon 90W lube???  There used to be a suction device for that that the service station people had.  About the size of a normal grease gun in the '60s, but with a clear tube on the end which was inserted through the fill/checking hole into the fluid.  The plunger was pulled back, the grease was pulled into the housing, then released into the waste oil receptacle, repeat until most was withdrawn, then fresh lube was pumped in from the barrel of 90W.  Same thing with manual transmission grease.

 

Good thing you were doing this during the warmer times of the year!

 

NTX5467

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2 hours ago, NTX5467 said:

There used to be a suction device for that that the service station people had.  About the size of a normal grease gun in the '60s, but with a clear tube on the end which was inserted through the fill/checking hole into the fluid.  The plunger was pulled back, the grease was pulled into the housing, then released into the waste oil receptacle, repeat until most was withdrawn

 

It's called a "suction gun". If you know that exists, then you probably know what an absolute horror they were to use. I would have been elated to be told about a secret drain bolt on any car....

 

For the masochists among us, harbor freight still has them.

 

https://www.harborfreight.com/oil-suction-gun-95468.html

 

 

 

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I must apologize.  I just went back to the manual and see I am wrong about draining the rear axle from the bottom bolt.  According to my manual the carrier is held to the rear axle by nuts.  The pictures clearly show the studs in the rear axle.  So I was wrong about this advice.

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2 hours ago, NTX5467 said:

Siphon 90W lube???  There used to be a suction device for that that the service station people had.  About the size of a normal grease gun in the '60s, but with a clear tube on the end which was inserted through the fill/checking hole into the fluid.  The plunger was pulled back, the grease was pulled into the housing, then released into the waste oil receptacle, repeat until most was withdrawn, then fresh lube was pumped in from the barrel of 90W.  Same thing with manual transmission grease.

 

Good thing you were doing this during the warmer times of the year!

 

NTX5467

 

It was 85W-140 B)

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  • 1 year later...
  • 2 weeks later...

I changed the oil in my GP's differential last month.  As with the Buick, my GP has a removable carrier with a pipe plug in the cast housing (rather than the cover).  Anyway, I took a short drive to warm the fluid and was able to suction out all but about 1/2 pint.  Refilled with Valvoline 85W-90.

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Odd that you do not have a fill plug, must be some type of odd job? All covers are welded on. If you already drained it out, you're going to have to thread the bolt again, then pull an axle and pour the lube in through one side. Be sure to jack up the side that you pull the axle on.

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