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Rear end and Transmission lubes for '37 LaSalle

Started by bigbeckley@outlook.com, June 08, 2021, 09:50:40 AM

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bigbeckley@outlook.com

Hello everyone. Articles talk about rear end and transmission fluids being compatible with the (yellow) metals in them... They talk about GL4 lubes... I have some x mission fluid that that says GL4 & GL5.... Just wondering if someone has comments on the correct fluids to use ?... Transmission is a '37 LaSalle. Thanks... John C. Lehman... CLC # 26365...

39LaSalleDriver

#1
I use NAPA GL1 Gear Oil in my 39 Lasalle for the transmission and differential.

www.napaonline.com/en/p/FCA65201
Jon Isaacson

1939 LaSalle 5019

LaSalle5019

#2
Quote from: USNTar on June 08, 2021, 10:35:19 AM
I use NAPA GL1 Gear Oil in my 39 Lasalle for the transmission and differential.

www.napaonline.com/en/p/FCA65201
Gl-1 is fine for a transmission or a spiral bevel rear axle but NOT for a hypoid gear axle as found in a LaSalle. The high gear and sliding forces in a hypoid gear requires an Extreme Pressure (EP) additive package that is not found in regular gear oil such as GL-1. Using GL-1 will lead to wear, then noise and finally premature gear failure.

GL-5 is the best hypoid gear oil available but has a tendency to corrode yellow metals in some extreme conditions. GL-4 is also a hypoid oil that is fine with yellow metals. GL-5 has about twice the amount of EP additives (sulfur and phosphorus) vs GL-4 which is why it has a tendency to corrode yellow metals. Not having taken my LaSalle's axle apart, I'm not sure it has yellow metals inside. The issue is mostly in using GL-5 in a manual gearbox with brass synchronizers. I really doubt you would have any issues with running GL-5 as the chance of issues of any brass or bronze (if there is any in there) bushings or washers I s low but rather than take any chances, I run GL-4 personally. I have never heard of anyone damaging any axle with GL-5. The issue has been in manual transmissions.

39LaSalleDriver

Quote from: LaSalle5019 on June 08, 2021, 07:29:24 PM
Gl-1 is fine for a transmission or a spiral bevel rear axle but NOT for a hypoid gear axle as found in a LaSalle. The high gear and sliding forces in a hypoid gear requires an Extreme Pressure (EP) additive package that is not found in regular gear oil such as GL-1. Using GL-1 will lead to wear, then noise and finally premature gear failure.

GL-5 is the best hypoid gear oil available but has a tendency to corrode yellow metals in some extreme conditions. GL-4 is also a hypoid oil that is fine with yellow metals. GL-5 has about twice the amount of EP additives (sulfur and phosphorus) vs GL-4 which is why it has a tendency to corrode yellow metals. Not having taken my LaSalle's axle apart, I'm not sure it has yellow metals inside. The issue is mostly in using GL-5 in a manual gearbox with brass synchronizers. I really doubt you would have any issues with running GL-5 as the chance of issues of any brass or bronze (if there is any in there) bushings or washers I s low but rather than take any chances, I run GL-4 personally. I have never heard of anyone damaging any axle with GL-5. The issue has been in manual transmissions.

The only reason I have been running GL1 is based on spotty information I picked up on this forum. Admittedly, this can be a subjective source. I would be more than happy to defer to your and others experience in this matter and immediately change what I use. Perhaps the biggest takeaway I can form is that GL5 would be "ideal" but there does exist a possibility that it's additives "may" affect any "potential" brass/bronze components, and thus be shied away from as a precautionary measure.

I did find this on a webpage for a Miller's Oils which is about the clearest definition I have seen:

"There are 4 levels of performance in classic gear oils and these really follow the development of gear design.

GL1 is the lowest level of performance and is only used in vintage transmissions. It is very similar to engine oil, having a very low additive content, but is available in much higher (thicker) viscosities to suit gearboxes with unsophisticated oil seals.  There are 2 products available in Millers Green Gear Oil range of GL1 oils as follows:  Millers Classic Green Gear Oil 90 GL1 and Millers Classic Green Gear Oil 140 GL1.

GL3 is the next level of performance and has very limited applications. Mainly specified for French and Italian (Fiat & Alfa) cars which had very soft synchromesh. It has very low EP (extreme pressure) performance and does not contain the concentration additives used in later engines.  We would recommend our product Millitran 4, SAE 50 for these applications.

GL4 is the first serious level of EP performance and is specified for many gearboxes and final drives from mid 1930's onwards.  Millers produces the following GL4 oils:  Millers Classic Gear Oil EP 80w90 GL4 and Millers Classic Gear Oil EP 140 GL4.

GL5 specification is for highly loaded hypoid differentials as fitted to most cars from 1960 onwards.  Millers offer the following GL5 oils:  Millers Classic Differential Oil EP 90 GL5, Millers Classic Differential Oil 85w140 GL5 and Millers Limited Slip EP 90 GL5 for limited slip differentials.



So to further clarify for my own thick skull, are you saying that it is best to run GL4 in both the differential and transmission; or should we be looking at using GL4 in the differential, and GL1 in the transmission? To make it more complicated, should we be looking at 80w90 or the EP 140 for either/or?
Jon Isaacson

1939 LaSalle 5019

LaSalle5019

Quote from: USNTar on June 09, 2021, 11:49:38 AM
The only reason I have been running GL1 is based on spotty information I picked up on this forum. Admittedly, this can be a subjective source. I would be more than happy to defer to your and others experience in this matter and immediately change what I use. Perhaps the biggest takeaway I can form is that GL5 would be "ideal" but there does exist a possibility that it's additives "may" affect any "potential" brass/bronze components, and thus be shied away from as a precautionary measure.

I did find this on a webpage for a Miller's Oils which is about the clearest definition I have seen:

"There are 4 levels of performance in classic gear oils and these really follow the development of gear design.

GL1 is the lowest level of performance and is only used in vintage transmissions. It is very similar to engine oil, having a very low additive content, but is available in much higher (thicker) viscosities to suit gearboxes with unsophisticated oil seals.  There are 2 products available in Millers Green Gear Oil range of GL1 oils as follows:  Millers Classic Green Gear Oil 90 GL1 and Millers Classic Green Gear Oil 140 GL1.

GL3 is the next level of performance and has very limited applications. Mainly specified for French and Italian (Fiat & Alfa) cars which had very soft synchromesh. It has very low EP (extreme pressure) performance and does not contain the concentration additives used in later engines.  We would recommend our product Millitran 4, SAE 50 for these applications.

GL4 is the first serious level of EP performance and is specified for many gearboxes and final drives from mid 1930's onwards.  Millers produces the following GL4 oils:  Millers Classic Gear Oil EP 80w90 GL4 and Millers Classic Gear Oil EP 140 GL4.

GL5 specification is for highly loaded hypoid differentials as fitted to most cars from 1960 onwards.  Millers offer the following GL5 oils:  Millers Classic Differential Oil EP 90 GL5, Millers Classic Differential Oil 85w140 GL5 and Millers Limited Slip EP 90 GL5 for limited slip differentials.



So to further clarify for my own thick skull, are you saying that it is best to run GL4 in both the differential and transmission; or should we be looking at using GL4 in the differential, and GL1 in the transmission? To make it more complicated, should we be looking at 80w90 or the EP 140 for either/or?
Jon,
The GL-1 is fine in your trans but definitely GL-4 or GL-5 in the axle. For our 130hp cars and hypoid offsets, GL-4 is perfectly fine in the axle.

39LaSalleDriver


Welp...guess I know what I'm doing this weekend...draining the differential.  ;D

Picking up some GL4 today and hoping that I haven't done any damage. So far, in three years I haven't noticed any issues, and with any luck never will. Thanks for the clarification and warning.
Jon Isaacson

1939 LaSalle 5019