What fluid should I use to change my manual AX-15 transmission on my 97 TJ? I was told to use Accel 80w-90 gear lubricant that is a GL-5. Any suggestions?
Any of the better grade 75w90 or 80w90's should do. I believe the factory spec is GL3/GL4. Most of the ones I have ever seen are filled with milk and metal shavings, but I still haven't figured out where to buy that stuff.
Don't use GL-5. The sulfur in the oil can cause pre mature failure to brass components inside the tranny. This is what the FSM and owners manual specified, but they corrected that in 2000???
GL4 Should be fine. If you go to a synthetic it may cause old seals to leak. I switched to Redline MT90 and I had to replace the rear output seal.
For some reason you do decide to get MT90 - Summit Racing had the best prices I found.