tow/haul

flysilverado · August 30, 2001

In tow/haul mode the shift points are firmer and it shifts at higher rpms so does this make the faster in the 1/4 or 0-60, the tires also spin much more but with the right launch i think i could be quicker.

Smitty00Z71 · August 30, 2001

No difference in speed, it's all in your head. Listen up people..... all that this mode does is help the tranmisson "predict" shifts better when under a heavy load. This is what I was told from a Chevy tech

gmcjoe · August 30, 2001

Crusing along at 35 mph or so, click the tow/haul button in/out. You can feel the trans and watch the RPMs change respectivly. I think this mode does more than just 'predict'. It is adjusting something.

Grant it, I don't know much about the transmissions in these trucks. Does anyone know exactly what happens when this mode is used?

Thanks,

Joe

MountaineerTom · August 30, 2001

Quote: from gmcjoe on 2:06 pm on Aug. 30, 2001
Crusing along at 35 mph or so, click the tow/haul button in/out. You can feel the trans and watch the RPMs change respectivly. I think this mode does more than just 'predict'. It is adjusting something.

Grant it, I don't know much about the transmissions in these trucks. Does anyone know exactly what happens when this mode is used?

Thanks,

Joe

I don't know what happens when in tow/haul mode, but like you said, I can feel the difference when clicking into it while moving. Speaking of that, could that hurt the tranny by switching it while moving?

Shaners · August 30, 2001

I believe tow/haul increases the line pressure for firmer shifts. I think the computer controls the shift point. You probably could increase your times with it engaged due to the firmer shifts and keeping the truck revved higher. I have also heard that it will allow you to over-ride the 98mph speed limiter, but I've never tried it...

Roofer · August 30, 2001

Shaners is correct about the computer controlling the shift firmness and when it shifts. A HPPIII reprograms the computer and it can make the shifts firmer. I use tow/haul when towing because it only shifts into OD when you are cruising. Then when you are around town or changing speeds often, you have 3rd gear power instead of the sluggish OD when traveling at 45 MPH. I wish it wouldn't switch to OD till at least 55. These new engines are a bit doggy in OD at 45, unless you want to hammer it and go into passing gear all the time. If you ask me, that is how trannies get eaten up. My advise is use tow/haul in D unless it is shifting alot, then just put it in tow/haul and 3rd. I think there is less trouble having the motor run at 2500 RPM's or maybe 3000 rather than the tranny shifting all the time.

Sorry for the novel.

Hope this helps,

Later