Rear Diff Replacement

I have an 04 RWD and need to replace the rear diff which has the 3.91 ratio… would there be any benefit in going to the 4.1 ratio? And if so would there be any extra work in order to do so?

 

Welcome.

 

Welcome to the forum Steve. Switching over to a lower gear ratio (such as a 4.10) can be beneficial, but it all depends upon what you do with your truck and if you have oversized tires. Many of the early base model v8 tundras came shod with 245/70-16 tires. The 265/70-16 were an optional upgrade. My 2000 AC 4x4 V8 came with 3.91 and 245/70-16 tires. I installed larger 265/75-16 tires then installed front and rear 4.10 3rd members that i removed from a Sequoia. I absolutely love the 4.10 with my tire size. Even if i installed a slightly smaller 265/70-16 tire i would still want the 4.10 gears in my truck. And FYI, my truck pulls double duty as a highway cruiser, firewood hauler, and sometimes a utility trailer.

If your current 3.9 gears are toast, then swapping over to a 4.10 won't require any extra work. Even less work and money if you find a used 3rd member that already has 4.10 gears in it (such as a 1st gen Sequoia).


TUNDRA TRUCKS-
2000-2003
3.91 - V8, 4x4, auto trans
3.92 - V8, 4x2, auto trans
4.08 - V6, 4x2, auto trans or manual trans
4.10 - V6, 4x4, manual trans
4.30 - V6, 4x4, auto trans

2004, Regular Cab or Access Cab
3.91 - V8, 4x4, auto trans
3.92 - V8, 4x2, auto trans
4.08 - V6, 4x2, auto trans or manual trans
4.10 - V6, 4x4, manual trans
4.30 - V6, 4x4, auto trans

2004, Double Cab
4.08 - V8, 4x2, auto trans
4.10 - V8, 4x4, auto trans

2005-2006
3.77 - V6, 4x2, auto trans
3.91 - V8, 4x4, auto trans
3.92 - V8, 4x2, auto trans
4.08 - V6, 4x2, manual trans

 

Rwd should be a 3.92 & you'll be looking for a 4.08 unless you plan to change the pinion flange.

 

ahhh...i forgot about the different sized pinion flanges.

 

When I had my 2wd Tacoma I regeared it to 4.10 and it was a big upgrade since I ran 33" tires. At the same time I ordered the entire unit from East Coast Gear Supply with a Detroit Truetrac and it was a HUGE upgrade for street driving and offroad. Check out their prices. It's nice because it's essentially a drop-in unit.