an you guys recommend me some oil for the diffs and the t case? and wen i bought the jeep i did the coolant, washer fluid, oil and power steering fluid. Any other fluids i have to worry about?

 

If its a wheeler then run Lucas 80-90 front/75-140 rear. If its a street Jeep run Mobil 1 80-90 front/75-140 rear. The syn will get you a little better mileage(maybe)

I run Dex/Merc 3 in the T-case. Some say you can run synthetic in the NP 231/242 but I can't speak for real life results as I have not tried it.

 

i am looking for the same info. anymore thoughts?

 

I know you wanna match your tcase fluid with whatever is in your transmission. And more than likely, that will be Dex/Merc III. And as stated above, your gear oil in the differentials depend on what you use your rig for. You would wanna use a heavier oil if you constantly go wheeling or use your jeep to tow.

 

i have a dana 30 front and a chryco 8.25 rear and i go wheeling 5-10 times a year

 

Then I would personally go with this if I were you. And remember that if you ever submerge your axles in water or constantly do when wheeling, you would wanna change the differential fluid more frequently, if not right away.

 

why do i have to run 80-90 in the dana 30 and 75-140in the 8.25? they don't use the same?

 

What method do you use to empty and replace fluid?

 

For a street only, no towing ever Jeep, yes 80-90 is fine in the rear. For the extra insurance, go with the heavier fluid.

 

would it be bad to run the heavier fluid in the front too?

 

I recommend the lighter oil for a high pinion axle

 

here is a link i found that answers all questions.

this writeup is for one diff only, you will need 4 bottles of gear oil if doing both diff's.

http://www.4x4xplor.com/diff-service.html