AX-15 Fluid Change

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

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.

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.

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...

at 180.000 i switched to redline.

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

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..

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.

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