I have 3.73 in my truck i would love to change to 4.10 or 4.30 so i think i have 4 speed auto tranny and tow 18,000lb,s a lot would it help on big hills to change gears ? on a 6% grade that is 5 miles long i can run 50 mph but thats staying on it all the way and i mean on it any help would be great thanks

 

With 35's I say 4.10's FOR SURE! I had 4.10's in my old SRW with 35's and towed 18k +or- a grand or so. Went down to 33's, world of difference! Now I have 4.10's with stocks (235/8017-DRW) and it tows great, same weight, maybe heavier!

 

If you put 4.10's with 35" tires your functional gear ratio will be 3.73. That's what I did with mine and it seems perfect now for pulling. If you want 4.10 gear ratio with 35's you are going to have to go all the way up to 5.10's or so.

http://www.rocky-road.com/calculator.html

 

Running 35's, will the change to 4.10's hurt the mpg's?

 

Yea i would like to know this to?

 

I get 19.5+ local mixed driving. The 4.10s will make it feel and tow like a different (much stronger) truck. Lower gears also put the trans gears closer together which is another big improvement. The engine will work easier and less downshifting. Big tires alone is a good reason to change. Craig