ive got a 01 chevy 1500hd and it already gets horrible gas mileage....by using the tow/haul button when towing something will it use more gas than if i had it off while towing it

How much does it take to overhaul a transmission today?
BTW what do you call horrible mileage?

I've got an 02 chevy with a 5.3L that gets 18 MPG highway. Does drop to 14 MPG while towing in haul mode. I don't think that's too bad. Can't afford a new transmission by not using it. If gas keeps going up, I'm going to be limited to Pool and Grapevine and trolling motor only.

Tow haul will make the shift points later but you will still have od and converter lock up. the transmission in that vehicle would run about $1800
in a dealership or much cheaper with someone doing it at night.

I have an '03 Chevy and the manual stresses about using the tow haul button to prevent damage. It does raise the RPM on the shift point and it also has a much more aggresive shift to eliminate slipping the clutches with a load. I think I get about 14 MPG when towing, and I do try to limit my speed to no more than 65MPH even on the interstates where it is 70MPh. I think if I drive closer to 60Mph my milage improves when pulling the boat.

well i get about 9 with it off mines got the 6.0liter v8

Ir should get better than that even with a 6.0 and tow haul on. Yow may have a tcc problem, also they were well known to have fuel regulators leak
and cause all kind of problems. this is an easy fix.

His truck has the 6.0L with 33s though..

I guess he forgot to mention the 33s. Even with the 6.0 most the customers I talk to get 12-16
depending on driving style, but that is with stock tires.

sorry bout that i guess that makes all the difference and have u talked to anyone that has installed a chip in theres

What are you towing ? My Xpress only weighs about 800# and I get no strain with it. Gas mileage has not fluctuated. Now if your pulling a 20ft glass loaded Baystealth at 30,000#, that might need the tow/haul override.

I have never used my Tow\Haul on Chevy 2500HD with the 6.0l or my Chevy duramax while towing the boat. For a big load where the truck is straining i will use it. Even with T\H engaged it should lock up in OD on flat terrain. Of course with 33s that will reduce your towing power.

Do you re calculate your mileage due to 33s? They will reduce the amount miles actually travelled on your odometer.

An aftermarket performance chip will increase power but no matter what they say will still decrease mileage.

Hey bmcd, you should never have to worry about tow haul with an allison. That is probably the best transmission for towing something.

I have a 5.3 motor with a program in it. The mileage goes down from 15 to 11.5 when pulling my boat with the tow /haul on, BUT.... it pulls so good!