Aug 15, 2007 · I'm sure this in the archive somewhere, but here it is fresh. What’s the difference? The performance requirements for automotive gear lubricants depend on their intended use. API …

Feb 11, 2010 · I don't like GL-1 gear oil and wanted something "better" in my transfer case and transmission. GL-1 is hard to find, and finding one with a corrosion inhibitor is even harder! So I …

Mar 18, 2007 · Hey, Have any of y'all used the Napa 90W GL1 gear oil in your diffs or t-case? I found a good price on some in the 5 gallon pail at my local store. It...

Jul 11, 2005 · The spec lube is 90w GL1. It is safe for all the bearings, works well, and is cheap... If you do use a GL5 (more modern and usually in a multi-viscosity such at 85w90 or 85w100) make sure …

Jun 26, 2012 · I went to get my gear oil today and quickly discovered that everything is GL5. I don't want to mess up my jeep but I cannot find GL4 for the life of me. I did see a GL1 gear oil, would that work …

Mar 29, 2013 · Napa and Tractor supply co... you want GL1 aka old Ford tractor gear oil. It's been covered a million times on here, if you search for it.

May 13, 2008 · I've been told by a couple of respected mechanics in my area not to mix GL1 gear oil with GL5 because it will turn into a tar like goo . That said, does the gov still use GL1 in the trans/ …

Dec 18, 2006 · I was looking for a source of gear oil and came across this MIL-L-2105 : Former specification equal to API GL-4 performance level. MIL-L-2105 B : Mono-grade automotive gear oil …

Jan 20, 2005 · GL-1 vs GL-4/other I seriously want to apologize if this has been covered already; I did not read all threads dealing with this issue. But I am referring to LO 9-2320-209-12-1, which is the …

Feb 11, 2010 · Hi Jon, That is interesting data.... I have learned something new. But I don't think it means that 50wt motor oil or a 50wt "transmission oil" are interchangeable with SAE 80/90 gear oil....