Synthetic blend gear Oil for 94 YJ SE

[ghostsmoke]

My son's and I bought my wife a 1994 YJ 4X4 with the inline 6. We have changed the oil/oilfilter and after 200 miles change the oil and filter again and using a synthetic blend oil (10w-30w). It has 145000 miles on it and the owners manual recommends 75w90w gear oil. Anyone here have any experience using synthetic blend 75w90w gear oil. the synthetic blend engine oil is doing great as far as the engine is concerned. Please jump in if you have an opinion or experience or know of someone using the synthetic blend gear oil. thanks Ghost

 

[clydethepirate]

Well if its not Bob!
Finally found your post on here.
Welcome to Jeepz

 

[Bounty__Hunter]

Use a synchromesh or Redline MT90. Stay away from GL5 rated gear oil as it will ruin the transmission.

 

[jfrabat]

Are we talking about differentials or transmission? I STRONGLY recommend the MT-90 for the transmission. For the differentials, just use regular oil and change it often. And yes, GL5 WILl ruin the synchros (it eats yellow metals, which your synchros are made of!). If you cannot find MT-90 or Synchromesh, make sure the oil has the rating GL-5 MT-1 rating (without the MT1, say goodbye to the synchros!).

 

[JohnnyO]

This:

Are we talking about differentials or transmission?

Synthetic or synthetic blend will last longer, protect better, and give some infinitesimal increase in fuel economy. That said, Jeepers who frequently off-road and get the axles under mud and water need to change the axle lube often and in those cases there is no point in spending the extra money for the good stuff. :shades:

Some manual transmissions and transfer cases call for ATF, so make sure you're using the proper lube for your application.

 

[jfrabat]

This:
Some manual transmissions and transfer cases call for ATF, so make sure you're using the proper lube for your application.

His is a '94 YJ with the I6, so he should have the AX-15, which calls for GL5, but the GL5 will eat out the synchros unless it also has the MT-1 rating... I would just get MT-90 online. This will even help make the shifting by making it a lot smoother.