Manual transmission question on a Jeep wrangler 4.0?

Question

I have a 2000 jeep wrangler 4.0 with a manual tranny. I wanted to change all my fluids before the winter here (im in upstate Ny, ft drum) started. I looked in manual and it said only use Mopar, im assuming because its Chrysler affliated. A mechanic said its just reg. 80-90 gear oil, so i changed it but now i looked online and it says use 75-90. Do I need to empty what I used or are they pretty similiar where it wont matter?

Answer 1

Nah dude wouldn't go thru the trouble. Just change it to 75-90 let time u change it. If you don't no big deal nothing will get hurt.

Answer 2

there's not much difference in the 2, I'd just leave the 80/90 in