Originally Posted by smokinjoe72
I am going to change out my diff very soon. My '10 came with 3.21 and I tow 7K lbs. The best way is purchase the carrier, no clearances to set. Just pull the axles and install.
Used carriers are about $600 rear. Front carriers are even cheaper.
Anyone have thoughts on if the 4.10s are the way to go or will my MPG suffer when not towing (only tow one weekend p/mth).
FYI, I towed with the 3.21s and it was just brutal - as I knew it would be. 8.1 mpg
You may want to double check this. Third members, like those found in 9" and toyota rear ends can be swapped like this, but not a conventional differential. You can't just replace the carrier, the ring gear and pinion gear are a matched set. Anytime you change the carrier, ring gear, or pinon gear, you have to check the pinion depth, gear mesh, and backlash. A thousandth of an inch difference in the machining can make a huge difference in the life of the gears.