I found an article the other day stating that only GL4 lubricants should be used in the rear axle, since GL5 lubricants would harm the bronze washers. I found a lub the other day that is supposed to work in place of GL4 and GL5. It is a 90/140 weight. I use the 90# in my Moore transmission. What is the best to use?
Any one have an opinion? I would really like to hear it. Thanks
I think this is a lot of internet worry with no substance. The GL4 lubricants have been used for decades in manual transmissions with bronze synchro rings. I've used nothing but that in my T's. Some of my cars have been in the family 65 years, and no damage from the GL4 lubricants has been noticed in the Ruckstell axles or Columbia rear axles or the brass thrust washers.
This gets discussed every so often. After lots of discussion, it's usually determined that nobody has ever seen such a failure.
Thanks! That does help to know I am on the right track.
You can always use synthetic gear oil.
Why not just go buy some GL4? It can still be had, but synthetic doesn't have that nasty smell that the regular stuff has.
Straight GL-4 is getting a little more difficult to find. Typically it is GL-4 / GL-5 compatible. NAPA carries Sta-lube brand straight GL-4.
I have a Ruckstell with modern bronze thrust washers. I recently drained it and there was a noticeable bronze glint in the pan. I can't prove that it's from the GL5 type lubricant, but being aware of the past discussions here on that topic, I replaced the lubricant with GL4 type. I believe I was able to find some at NAPA.
I put in a GL4/GL5 compatible in a 140#. It is rated really high but I am not sure it is best for the T.
The best deal I have found for synthetic gear oil is from McMaster Carr. Approx. $35.00 in a 1 gal. container. It does not attack bronze.
I learned the hard way what 90/140 conventional gear oil can do to bronze gears and bushings in my 1910 two cylinder REO.
The synthetic gear oil does not turns a bronze color like the other did.
Just sharing my experience....not looking to get in an argument on this issue. I also use a Texas T water pump and distributor along with 10-30 synthetic oil in my T engine and no slingers.....Smile!
I looked at the jug of gear oil. I actually put in G4 at 140#. This middleheimers is getting worse. That should be the best and safest from what everyone is saying.