AX 15 gear oil

[Eagle]

Mike --

So we can standardize on GL-3 for all years of the AX-15? Good, that's easy enough for my tired brain to remember (I think).

What about the BA10/5? Still GL-5 for that, or should we also use GL-3 in that one? Could I run that Pennzoil Synchromesh lube (which has NO GL- rating) and Mr. Moly molybdenum (non-sulphide) additive for the extreme pressure additive?

 

[RichP]

I'll throw my .02 in here. When this question first came up a long time ago I went to the mobil site and asked the question, aparently alot of others did too.
They more or less waffled and said use what the manufactures recommend. That said I have been running mobil-1 90W gear oil in my AX-15 for the last 180,000 mi or so. Switched about the same time I did the TC and both diffs. The mobil-1 eliminated that cold blooded second gear shift on cold mornings.
The mobil-1 atf in the TC eliminated the grinding going into 4lo and back out again. I'm happy with it...
The 'multi GL' rated lubes can't be, GL-3 = no sulphur GL4/5 = sulphur so unless it's some kind of smart bottle that identifies the tranny as you are pouring it in and withholds the sulphur if it sees and AX5 or AX15 theres no way it can meet all the specs.
As for going back to the dealer supplied AX15 lube, no thanks, I like the way mine shifts on cold mornings and don't want to go back to fighting the stick again.
I did shoot an email to redline and the respons I got was MT-90 is OK in the AX5/15 tranny. If I happen to see some around I may pickup 3 quarts and put it on the rack for when I go thru the 3/4 of a case of Mobil 90# I have left over...

 

[Bounty Hunter]

Re: From what i have determined......

It is the zinc additive in GL-4 and 5 that is the material distructive to the brass synchros used in a number of Jap transmissions.

It's been my understanding up to this date that it's the high sulfer content of GL5 that is highly corrosive to the soft brass synchros of the AX5/15 trannies. Google 'sulfer corrosive synchronizers' and you'll find a ton of info on this out on the web.

There is no year cutoff to my knowledge where the synchros were changed in these trannies. I wouldn't use GL5 in any of them. I've used Mobil1 in the past and it has prooved to eat synchros.

I now use only Redline MT90, and MTL is acceptable depending on the climate. Get mine at www.summitracing.com and it's a lot cheaper than the stealership juice. Redline is rated a GL4 yet it states it's specially formulated to be easy on the soft brass synchros. I've yet to have a problem with it, not even the glitter in the fluid that GL5 gives from eating the synchros.