I need a little help, Fast. Please?

Everything i hear says DO NOT use GL5 lube in a ax15 or ax5 manny tranny.

My FSM says use a 75W-90 GL-5 lube.

Should i go with what the manual says? Or what the common belief says? I'd rather not have my synchro's dissapear.

85xj4dr said:

Everything i hear says DO NOT use GL5 lube in a ax15 or ax5 manny tranny.

My FSM says use a 75W-90 GL-5 lube.

Should i go with what the manual says? Or what the common belief says? I'd rather not have my synchro's dissapear.

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Do not use GL-5 - GL-3 is preferred, GL-4 is acceptable. I know what you're looking at, but they're wrong.

The AX-series gearboxes use bronze synchroniser rings, just like the older boxes (ahhh, the old Muncies...) The problem with GL-5 is that sulphur was added to enhance EP lubrication properties.

Why is this a problem? Sulphur, in hot environments, is antagonistic to copper. Bronze is a copper-based alloy. Run GL-5 long enough, and your drained gear oil will look like it has gold flecks in it (that's your synchroniser rings. Oops...)

So, don't use GL-5. Transmissions aren't built like they used to be - many have aluminum synchroniser rings. Those that don't (NV3550, NV4500, and the like) usually specify some spiffy synthetic lubricant instead of GL-3, GL-4, or GL-5.

don't use 75-90 gl5. find yourself some redline mt-90, can't go wrong with that.
EDIT: 5-90 beat me to it. a bit more detail too...

Thanks alot, guys.

Also, the manual was a misprint.

Ten High said:

don't use 75-90 gl5. find yourself some redline mt-90, can't go wrong with that.
EDIT: 5-90 beat me to it. a bit more detail too...

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I find it doesn't hurt to tell someone not only what or how, but why as well...

redline mt-90.....kinda pricey though

jeep ride said:

Another good option for ax5\ax15 tranny is pennzoil synchromesh gear oil.

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Yech. I've cleaned too much Pennzoil out of engines over the years...

I use Sta-Lube GL-3, it's fairly easy to find.