80w90 GL3 or GL4 gear oil.
DO NOT USE GL5 Gear oil as this will eat away at the brass syncronizers in the transmission.
I prefer Pennzoil synchromesh
Manual is an AX5, automatic is a 30RH.
The AX5 used in Jeeps calls for 80w90 gear oil.The AX5 used in Jeeps calls for 80w90 gear oil.
AX5
The AW4 trans uses Dextron III. The AX5 and AX15 manuals uses 80w90
The manual trans would be the AX5 5 speed fully synchronized.
AX5
Jeep Wrangler YJ 2.5 engine, trans is a AX5
Auto : 30rh Manual : AX5
The ax5, AX15 transmissions in a 1990 Wrangler use 80W90 gear oil.
Most likely ax15 for the 4.0 and the ax5 for the 2.4
The AX5 5speed works nicely.