gear changing

[boatbug]

changing from 321 s to 394 s what does it require

 

[Scram1500]

If it's 2wd just change out the rear diff and re-program ECU. If it's a 4wd, for what it will cost to complete, trade it for a truck with 3.92's. The whole front differential assembly will need to be replaced as the ring gear is welded

 

[silver billet]

Don't waste your money on this. There is no benefit to doing so unless you are trying to win stoplight wars while pulling a trailer. The difference between "designing a test" and "real world towing", a test makes it look like a 3000 pound difference but in reality on the highway or passing people there is literally 0 difference.

Your gear ratio is not in isolation from the transmission. They work together to get your final gear ratio, which means, you can either "downshift" your axle ratio (go from 3.21 to 3.92) or downshift your transmission (go from 5th gear to 4th gear), either one has the exact same effect: your RPMs go up, you make more power, you go faster. If your 3.21 is struggling to pull a hill in 5th gear, the 3.92 will be struggling as well, only in 6th gear instead.

Other than from a dead stop (where the transmission can't downshift), there is 0 difference when it comes to towing. You can find that backed up by reports of other guys have owned both gears.

Gear ratios are terribly misunderstood by many people.