Changing the gear oil in the diffrentials this weekend. How much will I need and what is a good 75w-90 oil to put in them? I run the truck hard and tow quite often (8000#). My plan is to stay with the schedule b service chart from the owners manual. But was wondering If I should do the trans and transfercase also? Any suggestins. I know it says to do the trans at 30,000 just wondering of I'm throwing my money away doing it early...
Thanks,
Tim

 

Front differential 4.75 pints
Rear differential 7.65 pints
Differential cover bolt torque 30 ft/lb
Do not over tighten them. Others have broken them off.
I use Mobil One synthetic 75/90W gear lube.

Unless you see a bunch of metal shavings on the magnetic fill plug, don't even bother to remove the cover unless you just want to take a peek inside. I took mine off the first time but now just loosen the bolts enough to allow the diffs to drain. My fluid has been very clean and free of metal shavings both times I have changed the fluid. I personally think 15K intervals is over-kill. I will continue to change it at 15k until the 7/70 powertrain warranty expires, under protest of course.

 

I am going to use Redline 75W140 front and rear on the diffs. That is what my dealer recommended. I started to do the rear last night buth the gobblins and ghosts kept interupting me!!!

 

My first gears went south at 12,000 miles using the expensive DC stuff. I had even changed it out at 6,000. When they put the new gears in it, the tech recommended 75W140. I gave him five quarts of Redline 75W140 along with some friction modifier for the breakin period. I changed it out at 500 miles and after another 15,000 miles of HEAVY towing, the gears are still nice and quiet. If you are towing, put the heavier stuff in it. FWIW

Casey