I have a 03 QC with a 4.7. I think I have 3.55 gears in rear end. Has anybody changed gears to 3.92 or 4.10 to help out with towing a trailer?

 

4.10 are probably the best gear ratio you could get for a balance of performance & fuel economy with stock or slightly larger than stock tires.
Will help dramatically with towing performance.

 

i have never changed out gears before. is itdifficult and what mileage difference (generally speaking) could you expect to see from a change like this?

 

I had an 05 4.7 with factory 3.92's.... Gas was'nt bad.... and the only thing i ever pulled with it was a subaru that was stuck in a snow storm..But i think by looking at the lie-o-meter... I averaged about 14.5 to 15 City and Highway combined.....

 

I would have it done professionally, you have to shime it and it has to be perfect or it will tear itself apart. Ive thought about eventually going to the 4.10 for mine, though it should put it at 10800lbs, stick that in your ear tundra.

 

i went to 410 and it's well worth it. in fact, i'm spoiled now and wish i did 456.that's mytorque greedy side though. however, Hammer is right. 410 is a good all around gear. i didn't do it exactly for towing, but i do carry heavy stuff often. i'm quite happy with my choice.

 

Have them done.

Start a poll and you will see Have them done by a GOOD shop or you wish you did.

Once you put them in and there wrong 9 times out of 10 now there junk You be buying anouther set of gears $200.00 for gear set $110.00 for shim and bearing install set every time you have to redo the gear set more or less plus oil cleaner gear paint Ect if you can aford $350.00 to $400.00 a pop go right ahead.

Plus do you have all the Speciaity tools to do this job.

 

Along with the others, I too suggest having a professional shop (with a good rep) do them for you. It's easy to screw up and can end up costing you way more than you expected if you make a small mistake. I went to 4.56's, but also with bigger tires and have a heavier ride (do you have a 1500 or 25/3500 ?)...4.10's are a good ratio (IMO) if your gonna stick to close to stock or stock tire size, and wanna cruise the highway all day above ~75. Though, I've taken a few long trips (couple hundred miles) and had no problem whatsoever crusin' at 70, great mileage, no vibration, etc...

 

Couldn't you get the dealership in your area to do it?

 

I went to 4.56s from 3.55s specifically for towing in our 04 4.7 4WD. We tow a 4000# travel trailer about once a month. In the summer time, we tow on LONG trips - last year through California, Arizona and New Mexico. The difference between stock gears and the 4.56 is well worth the money spent. The tranny no longer searches gears. It will now stay in fourth gear (with tow/haul engaged) and only drops down when going up a grade. With the stock gearing the truck would constantly hunt between 3rd and 4th, even on relatively flat highways.

The only caution I have is that on steep hills, the truck will still hit 2nd gear. I have learned to just back off a little going up steep grades, run second gear at about 50 MPH and enjoy the scenery.

Oh BTW, my towing mileage went UP about 2 MPG with the new gearing.