Engine/Transmission (1998.5 - 2002) 3.55 vs. 4.10 what do you think?

[TCluff]

i put some 35x12. 50x18 toyo mud terrains on my truck and went from 18 mpg to 12 mpg. i put a 5in exhaust and an edge ez and now i get 16mpg, what do you guys with 4. 10's get?

 

[Cummins724]

I have 33x1250x16. 5 on my rig & I do alot of highway driving. I average 19-21mpg, but my friend only gets 17mpg with the same setup. I learned that if I keep my box turned up that I'm not in the throttle much & get way better mpg. I was following him on a trip last summer to New Jersey from PA. I made it down & drove around all week on one tank. He filled up when we got there. Pressure on go pedal = mpg. I think his foot is a little heavier.

 

[SS]

I get around 16. 5 with 36" Denman Coyotes and 4. 10's (see signature). If I drive the same routes for maximum fuel economy I get 19. 5.



If I had it to do over I would order the truck with 3. 55 gears - I am always looking for 7th gear to bring the RPM down on the highway.

 

[Nate]

Perhaps with the 5/6 speed the 3. 55s are nice. My truck had 3. 55s and 35" tires. I found it downright sucked to pull my trailer, which is only about 8,000lbs. The engine was constantly lugging. Was fine empty though.



I put 4. 10s in and it tows alot better. 2000rpm is right around 72-73mph, so I just set it there (speed limit here is 75mph) and go.



Fuel mileage stayed the same. I get 16-17mpg empty and 14-15mpg towing the trailer.

 

[TCluff]

its almost time for tires and no way am i putting toyo MT's back on my truck. they hook up great in the mud but they weigh 81 lbs a tire! the BFG MT's only weigh 60 lbs a tire! Does anyone know how much it cost to re-gear our diffs?

 

[klaybus]

its almost time for tires and no way am i putting toyo MT's back on my truck. they hook up great in the mud but they weigh 81 lbs a tire! the BFG MT's only weigh 60 lbs a tire! Does anyone know how much it cost to re-gear our diffs?

When I checked about 6 mos ago Randys R&P wanted just short of $2k to do the R&R including parts! I'll live with my 3. 5s & go back to 285s next time it's tire time. I would have never guessed that going to 295s from 285s would cost me 2-3 mpg. Live & learn!



Clay

 

[SS]

the BFG MT's only weigh 60 lbs a tire!

Not sure what the death wobble experience has been on trucks with your Superlift kit, but I do know that C and D load range tires can allow it to happen. I had a set of C load range Coyotes with death wobble and changed to E load range Coyotes of the same size - no death wobble and no other changes. The extra weight per tire may be worth it as it surely has an effect.