'39-'41 non-corrosive trans lube availability?

oldrelics

Well-known member
So being in Canada, I have have yet to find a 80w90(or similar) gear lube that isn't harmful to soft yellow metals. I have the "600w" sold by all the vintage vendors but that is claimed to be "too thick" for the trans. Specifically, what name brands/specs are you guys using?
 
SAE GL3 oils are long gone now. SAE GL4 lubricants will work fine for older transmissions. GL1 is available from several sources like Restoration Supply Co. & Lubriplate distributors that carry SPO series lubricants and is advisable for real early transmissions or overdrive boxes with one way sprag clutches although GL4 should work.

FoMoCo recommended straight grade SAE 80 for most climates but SAE 90 was usable in hot climates. The multi viscosity lubes will work OK as long as there isn't a leakage problem with the slinger ring types. A person just has to use 85W/140 if it leaks.

Believe it or not, SAE 50 AeroShell W100 aircraft engine oil is the same basic viscosity as 90 weight gear lube and will work in most old Borg Warner overdrive gearboxes. It is an ashless dispersant type oil so it doesn't have enough sulphur to do any harm but you have to avoid the 100W+ because it has a TCP additive that WILL slip a sprag clutch.
 
I just realized I put GL5 in my wifes daily VW that requires GL4 120,000 km ago! And the trans is the only thing that still works properly! I think we are overthinking this crap....
 
I don't know personally, but someone who seemed well informed posted about this on here long ago. He said that the degradation of brass was only a problem at very high temperature, something like 400 degrees. If that is true this is just another pointless flap like the unleaded gas that was going to cause all our old car engines to blow up in the '70's or the missing zinc that will destroy our camshafts in the '90's...
 
Steam cylinder oil 600-680w (300-350w+/-), is typically yellow metal safe and its not made with any heavy metals.

I picked up 5 gallons of fina 680w for around $35. Probably a bit more now if it's still available at the oil depot.

Is it better then lucas 90-140w or any other heavier oil? No idea, I purchased it because they had it available. I don't think it matters that much.
 
Chevron Delo Gear Oil 80w-90 and 85w-140 use Borate technology rather than sulfur for Extreme Pressure. The borate is non-active, so it will not attack bronze like sulfer can.

Bruce may be correct that is is "pointless flap", but I feel better using the Delo product.

Neal
 
Brad-Penn GL4 was using GL5 till it looked like gold metallic paint and the synchros in my 39 trans went bye bye.....
 
Oldrelics: I am in Canada too. I got my buddy Gerry to pick up a case of GL-1 at NAPA in Palm Springs. In Canada NAPA doesn't sell the same things as they do in the US. Anyhow, simple solution, reasonable price.
Mike L.
 
I found out today I can get Redline MT90 here in town, and looks to be synchronizer safe, just unsure if the viscosity will be okay....
 
Oldrelics: I am in Canada too. I got my buddy Gerry to pick up a case of GL-1 at NAPA in Palm Springs. In Canada NAPA doesn't sell the same things as they do in the US. Anyhow, simple solution, reasonable price.
Mike L.


I can't stand the limited supply of products compared with the US....
 
So I just found some lube I am going to use:

Lucas Synthetic 50W heavy duty transmission lubricant . Contains no sulphur, phosphorous or metals.
Part# 10146

And available! Perfect!
 
OR,
I build transmissions and of course use and abuse them in my own old Ford,
ask the guys I've white knuckled.....85/140 available at NAPA, Carquest, Ford Tractor
store....etc.
Charlie ny
 
OR,
I build transmissions and of course use and abuse them in my own old Ford,
ask the guys I've white knuckled.....85/140 available at NAPA, Carquest, Ford Tractor
store....etc.
Charlie ny

ALL 80W90, 85W140 I've found here is GL5, including napa.......
 
Yikes. I almost blew it! Last fall I drained my ****** and refilled it with 85W-140 gear lube. I thought it would be better as it was more viscous than the 90 W that was in it previously. The new oil worked well after it was warmed enough, but, wanted to grind when cold. Well, after reading the "Ford Forum" and speaking to my good friend, Jay-in-MA, I checked the small print on the bottle and realized I had used lube rated GL4/5. I drained it immediatley and found the drainings saturated with that horrible gold swirling. As Jay suggested, I flushed the ****** with ATF and will replace it with the proper lube in the spring. Hopefully, I was able to catch this mistake before any serious damage was done. A lesson learned.
 
I have posted this before, it explains what works and what doesn't. Note it applies ONLY to their High Performance line.
 

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When did the syncro killer stuff come available? I've heard various times not to use ep oil in old transmissions, as it will eat the synchro rings and thrust washers. Ford used ep oil in these transmissions from about '35 I believe.
So my question is, did they relatively resently change the ep additive to a yellow metal killer? I have done lots of trans rebuilds and haven't come across yellow metals that looked "eaten" by something corrosive, normal wear ant tare, and Some abuse. Nothing more.
When did it change?
Thanks in advance.
Martin
 
I did a bunch of web searching on this about 10 years ago because I had a vehicle that the PO had used "corrosive" 90wt in. The sulfur compounds only become a problem at temperatures well above something like 200 deg. F. Back then, the Dodge Cummins crowd had bunch of failures from towing heavy 5th wheels thru the desert in the summer, their trans temps were WAY up there. I kind of doubt any flathead vehicles can generate that high of a trans temperature. But it can't hurt to avoid oils that could hurt.
 
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