Hi all,
How far back does the TSB go for the 8.25" rear ends? I am setting up my 1991 B250 for a 10500# total weight and am trying to pick between 75w90 and 75w140. My back gear is 3.90.
Thanks again! Steve

 

Well,
I chickened out and went with synthetic 75w140. I have an open differential and it took close to 3 quarts. I was able to fill it up without much fooling around.

I backed the van up on ramps to service the differential so after putting it back together I squeezed each bottle flat into the differential to get them pretty much empty as the gas tank is in the way of an easy fill. I then put the leftovers into one bottle and squeezed it flat one more time. After that I got the van on the ground with a catch pan under the differential and pulled the plug out. Just a drop came out so I lucked out and had it completely topped off.
Steve

 

Just a word to the wise: fill it to factory spec. Overfilling, esp with synthetic, will result in oil foam and premature wheel bearing seal seal failure. If you fill it after driving it and just dump gear oil in til if overflows, it will be overfilled by 1/4 pint to 1/2 pint. If you let it sit overnight the gear oil will drain down from the axles and filling it to the overflow point will be correct.

On a Chrysler Corp 9.25 rear end the capacity is 2.5 quarts.In the middle of moving and my service manuals are packed so I can't access right now but your 8.25 is likely different, The correct differential gear oil capacity should be shown in your owners manual.