AX15 Oil Question

[Brendan_91XJ]

I search the forum and it says that you can run a syn 10w30 for the gear case instead of the 75w90 GL3. Which should I be putting in the JS rig?

 

[5-90]

I search the forum and it says that you can run a syn 10w30 for the gear case instead of the 75w90 GL3. Which should I be putting in the JS rig?

Using engine oil is gearboxes is an old hot-rodder's trick - it helps to reduce parasitic drag and pumping losses from moving the heavier gear oil (I knew people who used to put straight 20-vis or 10-vis in Muncie SM420/SM465 and old Ford toploaders for street/strip use, but I think that's getting a bit light...)

I'd probably use a 30-vis engine oil in the gearbox if I wanted to run something lighter - JeepSpeed is going to flog things around pretty good (maybe even a 40-vis?) but you'll still be safe from dissolving synchro rings - since engine oil doesn't have the added sulphur that GL-5 has (and it's the added sulphur as an EP lube that causes all the trouble.)

 

[Ronbo]

I've stuck to Pennzoil Synchromesh MTF for at least a decade with zero issues. It's cheap and it's everywhere.

 

[old_man]

If you have been searching, you probably have read that the syncros in the AX-15 will crap out if you use a non compatible file.

 

[Jes]

I've always used Redline MTL. The old black box has 230,000+ hard miles on it and is still going.

Edit: In fact, my AX15 is the only drivetrain component left on my Jeep that is still origional.

 

[Brendan_91XJ]

If you have been searching, you probably have read that the syncros in the AX-15 will crap out if you use a non compatible file.

Hey Tom, how are things?
Minimum searching... What do you mean by non compatible file?

 

[old_man]

Sorry, I fat fingered it. I meant oil. The wrong GL rating will eat the metal. Don't know if the motor oil would work or not.

 

[crazyjim]

Run 10-30, Justin (XJJeeper19) told me Jeep's new official oil for the AX15 at the dealer is 10-30.

 

[Brendan_91XJ]

Sorry, I fat fingered it. I meant oil. The wrong GL rating will eat the metal. Don't know if the motor oil would work or not.

No Worries... I know GL5 is a bad from my searching, and you have to use a yellow metal friendly oil

Run 10-30, Justin (XJJeeper19) told me Jeep's new official oil for the AX15 at the dealer is 10-30.

Thanks Jim, I was working towards this answer!

See you Saturday? the 11th!

 

[badron]

Drag racers did use 10/30W in there sticks but that was do to the fact that drag cars seldom warmed there tranny up. The one or two burnouts was mostly for the tires. So a thinner tranny lub was needed for min drag and max speed. Thinning the lub for a dd or most offing is not a problem.
As is the case so often with drag racers they are willing to give up a little dependable for speed. Hell when I was racing we felt lucky if an engine lasted a weekend.
!0/30W would work fine in soccer moms jeeps. As long as she never tows heavy or places any long term high stress loads on her tranny and our beloved XJ was built for soccer mom. So any factory recommendation for lub would be for that type of use.
For us that place much heaver loads on our Jeep. Heavy long term towing in the heat or very hard offing, we may need to rethink them recommendation and use a lub more suited for our type of use. Changing the lub a little more often also works.
PS: For Slush-O-matic drivers. If you are running in a high stress long term situation? I would think about changing you fluid every 20 to 25k addon cooler or not.

 

[5-90]

Sorry, I fat fingered it. I meant oil. The wrong GL rating will eat the metal. Don't know if the motor oil would work or not.

Engine oil will be fine - it doesn't have the sulphur-based EP lubes of typical GL-4, GL-5, or GL-6 (now defunct.)

You can use "Performance Synthetic" GL-5, if the label specifically states it's "Safe for use with Yellow metals." Most synthetics are fine - but check.

The sulphur-based EP lubes used in GL-4 and GL-5 are antagonistic to yellow metal (copper and copper alloys - like the bronze used for synchroniser rings in the AX-15...) and you'll dissolve your synchros and drain them with the next oil change. This will make the gearbox harder to shift (it won't make it worthless - but you'll find double-clutching easier than standard shifting without synchronisers...)

 

[CumminsJeep]

Run 10-30, Justin (XJJeeper19) told me Jeep's new official oil for the AX15 at the dealer is 10-30.

yup. apparently thats what they are calling for now. however, synchromesh will do just as well.

 

[Brendan_91XJ]

yup. apparently thats what they are calling for now. however, synchromesh will do just as well.

This is what we went with, since royal purple is a contingency sponsor.