To Use Overdrive Or Not?

wayne1968 · October 31, 2008

I have a 92 gmc 3/4 ton with a 5.7 litre engine 4 spd auto trans and 4.10 gears. my question is can I use overdrive to pull my holiday trailer? max gross weight is 6000lbs, dry weight is 4500 lbs. I know most people say not to use overdrive for pulling a trailer but I was wondering if having such a low axle ratio would change this opinion

Thanks Wayne

merlin5577 · October 31, 2008

Ummm........as far as I know you can use your overdrive pretty much any time. The only time you really dont need it is to downshifting to help yourself up and down hills.

2000DV4.8 · October 31, 2008

Since your truck doesn't have a tow/haul mode, I wouldn't tow in OD. 6k is fairly heavy, and that'd be a lot of stress on the trans, even with the 4.10s.

merlin5577 · October 31, 2008

Since your truck doesn't have a tow/haul mode, I wouldn't tow in OD. 6k is fairly heavy, and that'd be a lot of stress on the trans, even with the 4.10s.

Even on level ground?

carneyman · October 31, 2008

I've always said that if the truck can pull it in that gear, and you can stop the truck at that speed, then go for it. If it feels like its struggling or you don't feel comfortable using OD, then don't.

2000DV4.8 · October 31, 2008

Since your truck doesn't have a tow/haul mode, I wouldn't tow in OD. 6k is fairly heavy, and that'd be a lot of stress on the trans, even with the 4.10s.

Even on level ground?

In my truck at least, it kicks into OD at about 38-40mph, which would be a LOT of strain on the trans when pulling 6k pounds. I'd say, if you're going to be above 55 mph on flat ground for any length of time, you can put it in OD, but anything under that is pushing the trans a little.

merlin5577 · November 1, 2008

I've always said that if the truck can pull it in that gear, and you can stop the truck at that speed, then go for it. If it feels like its struggling or you don't feel comfortable using OD, then don't.

+1 That is what I do. Unless I am going up/down steep hills, then I just downshift as a precaution.

nbscanuck · November 2, 2008

When you are in OD, your pump in the tranny doesn't move enough fluid to keep things cool. You WILL see a rise in temps and you WILL shorten the life of your tranny. I have driver info center and have watched the tranny temps climb in OD (up by 30 degrees), which is alot. Don't do it. You aren't going to get any better mileage, but you are going to save your tranny.

If you don't already have a cooler, get one.