AX-15 Fluid Change

[yardape]

I've let my manual tranny fluid go much longer than I am willing to admit. Its my very dark secret. :gag:

Given that information, would it be a mistake to refill it with synthetic? I'm asking due to all of the cautions posted about doing the same with the engine. TIA

[Dr. Dyno]

I don't think you'll have the same problems refilling the tranny with synthetic as you would if you started using synth in a high mileage engine. The worst thing that can happen is a gasket or seal could leak slightly so don't sweat it. Refill the tranny with synth and enjoy the smoother gearchange.

[87manche]

I was told not to use a GL-5 rated oil in my AX-15. Apparently the sulfur eats up the syncros. I was recommended Redline MT-90 for a synth oil.

[otto]

x2 on the RedLine, great stuff. And no, you won't have any problems changing to synthetic oil in your transmission. You'll wonder why you didn't do it sooner...

[XJ_ranger]

at 180.000 i switched to redline.

I called them and used whatever they recomended - it slips me at the moment...

[RichP]

I'd go with redline, I have had mobil-1 gear oil in mine for the last 200,00mi but I bought a case of it back in 99 and just used the last quart. The old M1 had no mention of GL5 on it, the new mobil-1 does so to me thats now out. Next change I'm going to Redline rather than risk the GL5 issue. I for sure don't want to go back to the dealer/oem stuff, too brutal in the cold weather..

[Matthew Currie]

I've had good luck with Valvoline synthetic in mine. It says GL5 on it, but it appears not to have any sulphur, and I haven't had any problems since I put it in. That was probably something like 120 thousand miles ago, and I'm up to 253K. I check the level every once in a blue moon but that's all. It's still much quieter and better shifting than it was when I first got it at 110K. When I drained the dino oil it was filled with bronze sludge, but whatever it looks like in there now, it's working, so I'm not disturbing it.

[yardape]

Thanks guys,... the Red Line is in.