Hey I just bought my first jeep, its a 90 wrangler sahara edition with the 6cyl and 5spd trans. I went to Oriellys to get gear oil and they gave my synthetic 75w90. Is the synthetic required or could i just get regular 75w90? Thanks.
For the trans, the factory recommended straight 30-weight motor oil. There was a dealer service bulletin update about it. Other than that, it doesn't seem to make much difference either way between synth and regular. It waas designed for regular but either way will work.
BTW welcome to JF, you've just found one of the best jeep sites anywhere!
***--- Wrecking Crew member ---***
"I've prolly been around longer than you think"
If the ax5 or ax15 was built properly and you can customize the synchronizers so that they get more lubrication and less preload, you can in fact run 75-140 in it. its what ive been running since the day i learned to drive til now. Dana specifies 75-90 HP is recommended for front difs. rear diffs they want 80w-90. i run 75-140 in everything except the transfercase. i use atf+4 in the transfercase.