75W-140 or 75W-90

[LouisianaZJ]

Im running 75w-90 for break in of my hp30 and D44.

I am going to change the fluid after 500-1000mi. Im wondering if it will be safe to run 75w-140 synthetic f/r to quiet down the lockers and to help when i am hammering down on the axles. mpg is no concern

front lockright, rear full detroit, 4.56 gears

 

[RCP Phx]

No problem,its already listed in your manual!

 

[LouisianaZJ]

ok thanks

 

[Kejtar]

No problem,its already listed in your manual!

Actually yest and no. 75/140 is listed for rear not front in the manual but I run it and I have no complaints/issues.

 

[MENEZES]

yea, i ran it with a set of brand new gears in the rear and have been running it in the front for a while now. you'll be fine.