GL4 or GL5 front axle lube

[John0829]

There were some manual transmissions that used ATF and using a heavier oil would take them out. The oil passages were to small to allow the heavier oil to lube it properly.

 

[John_Mc]

Just a point to note:

Gear oils in the 80 and 90 weight category are not necessarily "thicker" than 30- 40 weight motor oils. The two lubricants use different viscosity scales.

Some people feel " thicker is better. but no... not so.

Sure seems thicker to me.

a 90 wt gear oil is the same viscosity as an SAE 50 oil, they are measured on different scales. It's the additive packages that differ.

 

[CalG]

There were some manual transmissions that used ATF and using a heavier oil would take them out. The oil passages were to small to allow the heavier oil to lube it properly.

ISUZU Trooper II manual trans used ATF.

A very nice gearbox in my experience.

 

[Texasmark]

I bought a 2007 65 HP tractor specifying UTF for the front axle. Bought the same brand in a 25 hp unit in 2016 and it said 80w-90 in the users manual and on the fill plug.

I had bearing failures on the 65 due to some mistakes I made in hopping clods with a bucket full of gravel. After I fixed the problems I decided to install 140 weight since I live in Texas, otherwise would have been 90w. Haven't had a problem since and it may be the oil or may be that I am more careful....but with the later year-model, much smaller tractor having gear oil specified spoke volumes to me.

 

[Robin Veerman]

You probably meant 75w140 right?

 

[Texasmark]

If you are answering me, yes....multi-viscosity heaviest weight commonly available.....I forgot the number for the cold viscosity.....maybe 80w. I think I bought some synthetic that was 75W-120 in a quart bottle once.

 

[big bubba]

I had a Toyota 4Runner with a 5spd manual transmission at one point.
Did a drain/refill and used GL5 thinking newer=better. Immediately became harder/rougher to shift through the gears. Researched and read it must use GL4 or you get this very problem. Did another drain/refill with the GL4 and it was back to smooth shifting.

Not sure what the mechanism is as to why the GL5 creates a problem in these; but the synchros are made of brass/bronze type alloy and it would follow that given the symptoms were with smooth shifting it has something to do with the synchros

Older Toyota manual vehicles call for 75/90 gear oil in trans & transfer case not 80/90.
(80/90 in differentials). both GL5. using 80/90 in your manual transmission could have accelerated shifter linkage & syncro wear, esp during winter in your location etc.

given OP's location, i'd go with 75/90 gl5 conventional gear oil for ft axle in tractor
best regards

 

[JethroB]

A bit off topic... One of my jeeps uses GL6 in it's rear axle (high pinion 9"). Try finding that stuff on a shelf at an auto parts store.

Or the GL1 my Willys calls for.