2k silverado regearing

[tsbrewers]

Hey yall, I have a 2k silverado that is pretty nuttless. I would like to re-gear it for a little more power. here are the specs right now,

2k Silverado
4x4 Extended cab
5.3 3.73 gears
285/75/16 tires ARE rims
Borla exhaust
K&N filter
custom chip programming

The problem is the truck has no power. it will shift from drive to over-drive and back and forth just driving down the highway. I pulled a small trailer last night and had to keep it in 3rd just to pull it, the trailer was basically empty.

So I would like to re-gear the truck and was wondering what I should go to? 4.12? 4.56? I also get terrible gas mileage now, 15 on a good day, last night w/ trailer was probably under 10 mpg. Thanks for any help/ideas.

Brew

[Tdragone]

This isn't applicable at highway speeds; but those tires look like BFG All terrain ta/ko's. There's a LOT more rubber around the tread area than on the stock tires.

This weight increase around the circumference will result in slower starts/stops.

Just food for thought..
-Tom

[rjeffery]

Yup. When I went from 255/70/16 General Americraps to 265/75/16 BFG A/Ts I went from about 17/19 to 13/15 mpg.

[tsbrewers]

yup that is what they are. I have always run these tires, and they were on here from the factory (waldoch conversion)

correct me if I am wrong, but wouldn't that help once i was actually at speeds? I was told that if I re-gear, my mileage would probably increase. But, I am not doing any of this for mileage though, I just would like more power. I do not drive the truck much, I have a work truck, so most of the time when I use this one it is pulling something.

So at this point, it is either re-gear or get rid of the truck. Which I can't afford the second option, so we are back to re-gearing.

Brew

[silveradofirerescu]

Going from 3.73 gears to 4.11 or 4.56 will actually give you worse mileage. Think of it as your engine has to spin more RPMs to go the same speed. It sounds like you have some other problem besides your gears that is causing a lack of power. When was the last time you check your fuel filter? Air Filter? I would try a good tune up first before jumping into a re-gearing project. 3.73 gears with a 4L60e should be plenty to do most daily pulling with no problems IMO.

[silveradofirerescu]

Also one more think to check is that you are not in 4WD Auto. That will kill your mileage and power quick. Looking at your set-up again you should have plenty of power.

[bigbadram51]

If your running 285's I wouldnt hesitate to regear to 4.10's or 4.11's. I know it wont kill your mileage, probably wont improve it, but def. make it much more driveable. My mileage didnt go down that much running 35's and 4.88's. When I switch over to 37's, that combo will be close to stock gear/tire ratio. If you look at the other full size man. most of them run much closer to a 33" tire (if not a 33) and have 3.92's to 4.11's or at least an option. Chevy factory tires are 31.5's on z-71's. You add an inch and a half talller tire that will have a pretty good effect on you power delivery.

[tsbrewers]

Ok, this week I brought it in to a local mechanic whom I trust. He jumped in and drove it around town and on the high-way. He said his gut feeling is that the torque converter is the problem. Says he agrees it is a dog (his words) and if it were his truck, he would replace the torque converter first, might be too "tight" and can't transfer the power from the motor through the tranny, or something like that.

he said he was going to call around to some tranny shops and see if they had heard of this ever being a problem. And said next time I get home from work early enough, we would jump in it, and he would hook up the computer and drive around. He figured after enough info, he should be able to know if it is the Torque converter or not.

Brew