Transmission Oils?

[Byron Warwick]

What are the recommended oils to use in our old transmissions. I'm running the original 1934 manual. Not asking what was originally specified, but what is readily available now. Same oil for the rear end?
Thanks. Byron.

[Vic Piano]

I use 85W-140 Gear Oil in the transmission and rear end on all our Flatheads.

[Old Henry]

What was recommended and what is still available are the same - S.A.E. 90 weight gear oil.

[David J]

Above freezing called for S.A.E.160 in 1934 & this is ford info . I use S.A.E. 140 moly in tranny,u-joint,rear end & steering with no complaints . There is ford info stating to use S.A.E. 140 in place of the 160 stuff . Like mentioned above S.A.E.90 is a good choice also . 85W140 is pretty thin compared to S.A.E. 140 but it will work also . The 140 moly stuff quiets things down nicely also .

[Old Henry]

Originally Posted by Old Henry

What was recommended and what is still available are the same - S.A.E. 90 weight gear oil.

I stand corrected. I was answering for my '47. '34 is apparently different. Sorry.

[russcc]

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Macs trans book recommends 90 to 140 depending on the temperature, if I remeber correctly.

[richard crow]

vic piano gave you the right amswer

[David J]

Hmmmmmmm

[1oldtimer]

Also if you go with a regular auto parts house, get gl4 NOT gl5. It's a little more difficult to find around here, I had to order a few qts extra.

[31chevy]

I thought it was supposed to be #600 weight oil, available at mac's & C&G ford. I use this in my 34 ford & 31 chebby. Both tranny & differential.
Gary.

[David J]

This is my choice and unlike some GL5 stuff this has additives that make it user friendly with brass . Goggle it . They also have it in S.A.E. 250 but that stuff is pretty thick . I'm definately NOT an oilologist but after seeing the absolutely amazing number of different opinions on what belongs in these cars I did some snooping & the Oldsmobile folks had some good articles on the changeover from the old steam cylinder oil to the S.A.E. ratings & SOME were saying that the old 600W stuff was about equal to S.A.E. 160 . Ford said to use 140 in the absence of 160 & that folks is all the info I need .

[Tom's36coupe]

good question, I have my trans apart right now and was looking through macs book too. They have a 600 weight oil for transmissions. Big difference from 600 to a 90, my trans has the later helica cut gears in it. Thanks for the direction.

[Byron Warwick]

I am still trying to source 140 viscosity oil in my area. I want to have the GL4 spec oil. I'll get to a tractor dealer soon.Byron.

[rotorwrench]

Gear oil hasn't changed a lot over the years but back then the SAE was in it's infancy when it comes to the gear lube ratings. It boils down to what you can get now. They always recommended Mild EP for early Ford transmissions due to the yellow metals used for bushings & blockers in there. The "Mild EP" indicated a lube with no additives for extra pressure. It's harder to find GL-1 lubes now but they are still produced by specialty companies like Lubriplate and a few others (available from any Lubriplate distributor or Restoration Supply Co). The 600W steam cylinder oil was never an SAE rating but several vendors sell a concoction that is about as viscous and it has oil in it so it will work if that's what a person prefers. GL-5 lubes are extreme pressure and were designed for hypoids like most rear axles are from 1949 on. A rear axle usually has no yellow metal inside so you can use any rated gear lube that won't leak out too fast.

Any oil is better than no oil. A lot of folks don't realize that SAE 50 or 100 grade aircraft engine oil is the same viscosity as SAE 90 gear lube since they are graded differently. In a pinch, some Aeroshell 100 straight mineral would work for SAE 90 GL-1.