Rooti

I have a 2007 NBS 1500 silverado extended cab. I want to change the 3.42 gears to 4.11 ratio for towing purposes. The one shop that was highly recommended to me says they do a lot of them and have never had to reprogram the ECM. They claim the speed sensors recognize and adjust out.

So any of you change the gearing and drive it the way it was?
I guess worse case senario is I have to buy a tuner later...

country_09

Yes you have to get the speedo corrected, also your brake lights will turn on without gettin it adjusted. I recommend a custom tune over a handheld tuner. Cheaper (250) vs a tuner (300+) and better results

Rooti

I have a top notch dyno tuner close to my house. Do you think it would be worth having it dyno'ld while I'm there? It is a stock motor with just a K&N filter in the stock box.

On my harley it was night and day difference in performance. Would I notice much more performance with the custom tune?

Rooti

Update: I got the 4.11 gears installed and took it to a well known performance shop to have everything recalibrated. The owner said as long as he was in the computer he would do some tweeking. Drove it to work the next day and got 17 1/2mpg doing 70MPH. It did seem like it had a little more torque and I noticed it was up to 2K on the tach.

Came home and picked up the 31' trailer and hooked up and got on the road and holy crap...It was pulling almost as good as before the trailer and not shifting around as much

country_09

Glad to see you chose to have them do some tunin on it. Very beneficial for you, 4.11s a good gear for what you're lookin for from the sounds of it!

Rooti

I did notice the AFM wasn't coming on anymore so I called him and he told me that's the first thing he always does is to turn it off...good for 2 MPG, he says its counterproductive. Now I'm reading it has torn up a few engines here. I use to watch it work on the screen and even on flat ground it just switched back and forth.

country_09

Yeah it's very useless. Goin in and out tears up the lifters from a few I've read. I've always seen em get tuned out and it runs better