Its time for me to change the oil in my ax15, I was wondering if anyone still
uses mobil 1 in their gearbox. I've ran it in mine for about 3 years no noticeable problems. I don't want to start a war just feedback from long term use please.

 

Guy that built my AX15 gave me a three year warranty, if and only if, I used Redline MT 90 in the trans.

 

When in doubt I revert to factory manual for towing applications. They don't recommend a brand but a specification. Find that same spec with your favourite oil brand and poor it in. You can't to wrong that way. Being an Amsoil dealer, i like using their site as they have a listing for almost any vehicle on the planet as to what type of oil to use, quantities, filters, even torque specs for plug. Amsoil.com

I used to give printouts to customer but its now accessible to everyone

 

Redline MT-90 for the win! Tried 10W30, AC Delco Synchromesh, and a bit of Lucas Transmission Fix. Doesn't even compare.

The AX-15 was not designed to run on engine oil. I'm not sure why someone would use engine oil in a gear application. The original spec is API GL-3 75w90.

 

Agreed. Any oil is better than no oil in a pinch but a lot of research was put in every component and what's best for them. I would definitely stick with the 75W90... Any brand. Of course I would pick synthetic first..LOL

 

Only problem with, sticking with 75w90, is that the 75w90 you get now is API GL-5 and it will eat the brass sycros in the transmission over time, that is why Redline MT 90 which is a 75w90 gear lube for manual transmissions with brass sycros is recommended by a lot of transmission builders.

 

I'm willing to try Redline MT90 but it's not easy to find around here, what about Royal Purple or Pennzoil synchromesh I can get that at a lot of places.

 

Good stuff. I think RP's Synchromax is a bit thinner than 75w90 (like Redline MTL) but some guys like it. RP's 75w90 actually might achieve the GL-5 rating without a ton of sulphur, worth giving them a call.

I actually got my MT-90 through NAPA

 

Thanks for the replys, I found a place that has the MT90 but they only have a couple of quarts in stock right now. Hopefully they get some more on there next delivery.