Other: Are SAE 90 Gearbox and SAE 50 Engine Oil identical?

[avantilover]

I received the latest copy of the Aussie Stude News today, and a fellow in NSW told the club at their recent meeting that "SAE 90 used for Gearboxes is the same oil as SAE 50 Engine oil."

Is this correct???

[DEEPNHOCK]

No, it is not the same..
There are additives in the gear oil that are not present in the engine oil.

[BobPalma]

'Don't know about Australia, John, but it wouldn't be correct in the 'States.

The SAE (Society of Automotive Engineers) ratings of various lubricant "weights" are based on the lubricant's ability to flow at a specified rate; the larger the number, the "thicker" the product will be, and the more resistant it will be to flow at a given rate for whatever test standard they have.

Further, the W designation indicates an ability to flow at a specific rate at zero degrees Fahrenheit, useful for evaluating a lubricant's ability to "work" at low temperatures. Hence the designations 10W and 20W, although you'll not see a 30W designation by itself because 30-weight is simply too thick to flow at the requirements for the W test, whatever they are.

Whoever wrote or spoke that should be asked for a clarification, at the least. And ditto what Jeffster posted about additives. BP

[Jim B PEI]

What Jeff and Bob said. One other thing to consider in addition to their sound advice is the *sort* of additives in any lubricant, especially gear oil. Modern formulations for current use might have additives that will actively cause damage to materials used in an old-style transmission like a Studebaker.

[powerhawkeye]

you should be able to smell the difference you can miss the odor of rear end lube

[N8N]

I believe that the viscosity scales for engine oil and gear oil are different, so they might be roughly equivalent in viscosity. But GL-5 and GL-6 gear oils have EP additives that engine oil will not. (they also contain sulfur, which can corrode "yellow" metals, so there are reasons you may not wish to use a GL-5 gear oil in a given transmission, as sometimes the synchros are incompatible.)

nate

[Paul Keller]

Some time back (one? two years?) a T.W. article (Co-operator) suggested using 40 or 50 wt. NON detergent, NON additive motor oil in place of gear lube for the BW T-10 four speed. The reasoning was that the early gear oil (circa 1960's) did not have the additives that current "hegh pressure" gear oils have now. The shifting on my T=10 improved dramatically, much easier and smoother shifting. The only source for the oil was at an airport that provided service for private (small) aircraft - Many of them require non detergent.
Paul TK

[Mark57]

Some time back (one? two years?) a T.W. article (Co-operator) suggested using 40 or 50 wt. NON detergent, NON additive motor oil in place of gear lube for the BW T-10 four speed. The reasoning was that the early gear oil (circa 1960's) did not have the additives that current "hegh pressure" gear oils have now. The shifting on my T=10 improved dramatically, much easier and smoother shifting. The only source for the oil was at an airport that provided service for private (small) aircraft - Many of them require non detergent.
Paul TK

Actually the original Studebaker produced shop manuals specified that 40 wt. engine oil could be used in the BW O/D transmissions instead of the 90 wt. GL-1 gear oil.

[avantilover]

Thanks guys, it sounded strange to me and I'll pass on the information. As for me, I use whatever my Ford dealer puts in Studebaelle.

[StudeRich]

FORD Dealer?

That does NOT sound good, John!

A New Car Dealer used to working on new Cars, would NOT have a clue, or the proper Lubricants to Service a Studebaker!

[Hawklover]

Look for Red Line Manual Trans Oil.........fabulous stuff.

[avantilover]

Worry thee not Rich, the guys doing my car are into old cars - the father of one actually operates an import business - you request a US model and they locate and ship it. My car is running perfectly, they are aware of the lubricants - here in Australia the ZDDP issue is non-existent - any parts I need I can source from Studebaker Queensland from whom I purchased a new suspension system (whatever parts were required) and I'm soon getting the rear springs re-arched with helper leaves (1 each side) , then a wheel alignment and that's as far as I can go for now.

[Paul Keller]

Further to trans lube:
The Nov 2010 TW (Co-operator) noted that their recommended lube for manual trans w/ or w/out OD is -"... GL-1 Mineral Oil, Red Line MTL (manual transmission lube), or Non-multi grade 40 wt synthetic motor oil". I believe that an earlier TW issue indicated that 40 - 50 wt mineral (non-synthetic) motor oil was also recommended - But have not yet found the artcle to confirm (will keep searching).
Paul TK

[Johnnywiffer]

In 1950, the oil originally recommended for the Studebaker Automatic Drive was 30-weight motor oil. By 1952, that was changed to Type-A auto trans fluid. Was it because the newer oils were better or just more expensive?



Since type A is no longer available and I never used it in a Studebaker anyway, I use 5w-30 in all my SAD cars with no apparent problems. And 5w-30 in all my manual Fieros, again without problems.





John