I have 3:42s and the truck seems to stumble a bit under 2500 rpm. I have a W4M tune with torque managment 80% removed. Would a gear swap to 3:90 or 4:10 make a big difference for the money? I only have 6 miles a day on the freeway to drive. The rest of the time I am under 60 mph. 1 or 2 mpg loss on the freeway wouldn't be the end of the world. Opinions? Also, what's the price range for a shop install?

 

I have gained mpg with the 4.10s and tune for under 65 mph driving. i am not sure how much, but I know that I have. The difference is night and day. You will not need as nearly as much throttle to get moving under normal driving conditions. Down shift points take a little getting use to. I do not believe you can go wrong with either gear choice.

In addition, when passing while in o.d., you will not need to down shift to pass. But, if it does, you will go around who ever pretty damn quickly.

 

Went from 3.42s with 31.8" tires to 4.10s with 31.8" tires before, you could slip a tire even in the rain, now it'll bark (no smoke) off the line dry.

 

went from 3.42's to 3.90's with a 31" tire it dropped me 4 tenths on the qurter mile. If i would do it again i would go with 3.90's or 4.10's day and night difference.

 

you shouldn't loose mileage depending on your driving habits. it would be useless to swap gears if you still had the TM but since that's not your case it would be a good choice for either of the gears. when my truck was nearly stock, (and still had TM) i went from 3.42 to 4.10's and added some et streets and it dropped me 3/10's in the 1/4

 

I am considering do a gear swap as well why would it be useless if he still had TM?

 

because the transmissions pulls power from the engine. there was a guy at the track with an 05 gto. i'm not familliar with their gear sizes but it was pretty similar going from 3.42's to 4.10's. his e/t did not change one bit.

 

Thanks for the info. I will have to keep that in mind.

 

Unless you drive highway 80% of the time, the 3.42's are too tall. I think GM only put those in there to claim better MPG on the sticker. I changed mine to 3.73 (front and rear for 4x4) and also went to a 1" smaller tire. Handles much better around town, where i do most of my daily driving, yet still gets great milage on the highway, if i can keep my foot out of it!

 

Thanks guys. Any suggestions on manufacturers? What size case does my truck have?