[davidpaul]

Has anyone tried any good old EP90 gear oil in their diff's ?

[bezerk1]

Valvoline SynPower 75W-90 Full Synthetic is what used in mine.  No issues so far.

[NMKawierider]

Valvoline SynPower 75W-90 Full Synthetic is what used in mine.  No issues so far.

Yeah I think that's what I used too. Good stuff. I don't think I would use straight 80 or 90 in these

[davidpaul]

Thanks guys

[ACIDICJO]

Has anyone tried changing those drain bolts with something you can put a socket over?

I find I'm stripping them a little bit more everytime I check the oil in it.

Also you guys are running that oil in both front and rear diffs? Excuse my ignorance on the subject guys. But I could of sworn the Manuel recommends two different kinds. 

[bezerk1]

The service manual does call for 2 different weight oil.

Front  SAE15W/40 SG
Rear  SAE80W/90 GL-4

I'm a rebel and used gear oil in both.  No problems yet.

[davidpaul]

The hand book seems to say 80w/90 for both front and rear, that's what I'm using in both.

[bezerk1]

I got that information from the service manual.  I think that the information in owners manual is different.  I would feel perfectly fine with gear oil, motor oil, or ATF.

[NMKawierider]

I got that information from the service manual.  I think that the information in owners manual is different.  I would feel perfectly fine with gear oil, motor oil, or ATF.

I wouldn't use ATF. It hasn't enough shearing properties for those types of gears in differentials as it is primarily a straight hydraulic fluid.. but..tractor hydraulic oil does and is used in many rear gear cases with wet brakes and gears like the ring & pinions.

[JocoNC]

Has anybody used Royal Purple oil in there Z Force yet? Engine and diffs? Just curious I have been doing research on different oils and I think I'm going with RP.

[NMKawierider]

Has anybody used Royal Purple oil in there Z Force yet? Engine and diffs? Just curious I have been doing research on different oils and I think I'm going with RP.

Don't. Unless you use their Max Cycle as it is rated for wet clutches. Don't use any synthetic in the engine unless it is rated for wet clutches. Also, the CFM reps told emersonsc, who is a dealer, that their engines were not designed for use with synthetic oil. Go a head and use synthetics in the diffs as it is no problem.

Now with that said, I am testing a different one that is rated for wet clutches and so far its the cat's azz...if fact the clutch actually hits harder and stronger.. but I need a little more time on it before I can recommend it.

[Bobbed06]

Amsoil, and Mobil One Gear Oils are highly regarded inn the off road community. Amsoil being the better of the two. I use Mobil One as its readily available in my Toyota FJ with locker.