Towing in overdrive

[FlaDon]

This has been an interesting and informative thread. I just got into camping (at my wife's insistence) this year and bought a 28' travel trailer (32' bumber to tongue). How little did I know about towing, pulled it home with my 2001 Silverado 5.3L truck, found out right away that the TT was too much weight.

Went shopping for a good used 3/4 ton used truck, found out diesels with low mileage and reasonable priced are two different things; they all had either high miles/lower price or low miles/higher price. So ran across a 2002 Sierra 2500HD with the 8.1L gas and Allison tranny and only 37,000 miles, at $12k.

Truck pulls camper great but I can't figure out which gear/mode that I should cruise in. I made a trip to the mountains in VA and was in tow/haul mode until I got to a very steep and long grade (going up). Truck downshifted and even tho turning 4500 rpm's, it would not do over 45 mph. That plus a horrendous loud roaring noises. I pulled over, took off town/haul, and proceeded on. I found out that in the "D" selection and without tow/haul, I could pretty much maintain 2000 rpm's and 60 mph except on very steep hills. There I just built up speed going down and usually pushed up to 3000 rpm's near the top of the hills. Seemed like much less strain on the engine and tranny that way.

Now I am totally confused on how I should tow on flatter land. Tried towing in tow/haul and "D" on a recent coastal trip. The truck did ok cruising but on minor grades, it would shift down and run up the rpm's while taking what I thought was too long to come out of it. Then, in town, as I approached my stops, the trans would downshift heavily and really sounded like it was in a strain.

Back on the road, cruising without the tow/haul, I did not have these problems. So, my question is, is this normal operations for the Allison? Is this downshifting of the tranny and up powering of the engine to the 4000+ range ok? What about the "rough shifting" at times?

Even tho this is an '02 model, the previous owner did not service the Allison since he was nowhere near the 50,000 mile mark. I thought I might go ahead and get it service although the fluid looks and smells normal.

One other thing, on the trip in the mountains, I was running around 190-200 degrees on the trans. On the coastal trip recently, I ran as high as 211 degrees (it was 100 degrees day tho).

Since I am a novice at this towing thing, any help or advice will be greatly appreciated.

Check the service history on the tranny. Rough shifting was a sign of the flexplate failure on my 2001 8.1. It just got a fluid/filter change on the tranny as the repairs were 50K ago.

 

[Diamondpilot]

Hey, I know it's being lazy and not looking it up myself, but what is the last year GM diesel pickups were made without DPF stuff? Business is picking up in areas I didn't expect and dropping in others. As you know, I'm pleased with my '06 PSD but most likely need to add another truck and trailer. I had the Dodge for 10 years and now have the Ford. I figure I ought to drive the latest offering from GM and maybe go that way this time if they drive okay.

You ever get that vomit taste in your mouth? It just happened to me. Why not just get another F-350 6.0 Ford and be done with it. Then you will have 2 real trucks.

Now to answer your question it was the 2007 model year. The change over came half way through the year. The first half with no DPF was in the Classic Body Style like Builder has. The new body style with the snow plow front bumper and later have the DPF.

Ok, off to brush my teeth with bleach!

Chris

 

[Builder]

Hey, I know it's being lazy and not looking it up myself, but what is the last year GM diesel pickups were made without DPF stuff? Business is picking up in areas I didn't expect and dropping in others. As you know, I'm pleased with my '06 PSD but most likely need to add another truck and trailer. I had the Dodge for 10 years and now have the Ford. I figure I ought to drive the latest offering from GM and maybe go that way this time if they drive okay.

I needed some time to think about this because I had to go back and research how you view GM.

After reading several of your previous comments, because of your extreme negative bias towards GM, buy another Ford since you like them so much. Judging by your own typewritten previous comments about how much you hate GM, you would probably be throwing fits as soon as the first minor thing went wrong.

Here's an example:

]No, no, no, no, no. Tell everybody to buy GM. I lost enough money from that freakin' bankrupt company that they owe me a free truck. For buying their products and buying their stock over the years they have most definitely cost me more than any possible breakdowns from any number of vehicles could have cost me. I need more people with blinders on like "Builder" out there banging the 'buy GM' drum!! Hopefully there will be enough people buy from the bankrupt Government Motors to drive up their stock from "junk" status to at least "poor" status.

Quite to my surprise (and everyone elses that have PM'd me) is that the very next post the next day, you actually say you want to buy another new truck & trailer, but the real shocker is that you're talking about buying a GM now:

I figure I ought to drive the latest offering from GM and maybe go that way this time if they drive okay.

HUH?

I guess it's your inconsistent, indecisive, 180 degree turnaround style posts that are the most entertaining aspect of all this.

I like to buy the best truck available at the time I purchase. If everyone did that, they'd get the best truck for their hard earned money and not have to worry about what anyone thinks!

 

[herd]

Check the service history on the tranny. Rough shifting was a sign of the flexplate failure on my 2001 8.1. It just got a fluid/filter change on the tranny as the repairs were 50K ago.

How does one go about checking the service history on his truck's tranny? Is this something I can do on the internet or would I have to take it in to a dealer? tks

 

[Dargo]

You ever get that vomit taste in your mouth? It just happened to me. Why not just get another F-350 6.0 Ford and be done with it. Then you will have 2 real trucks.

Now to answer your question it was the 2007 model year. The change over came half way through the year. The first half with no DPF was in the Classic Body Style like Builder has. The new body style with the snow plow front bumper and later have the DPF.

Ok, off to brush my teeth with bleach!

Chris

Thanks Chris. I see that he can dish it out but clearly can't take it in return. LOL!

 

[Builder]

How does one go about checking the service history on his truck's tranny? Is this something I can do on the internet or would I have to take it in to a dealer? tks

You can do either one. If it were my truck, I would take it to an Allison authorized service center and have a tech check it out. You'll just waste a lot of time on the computer. Sure, you'll find TSB's on them, but what good will it do you until you have it checked out.

Look for a GM dealer with an Allison tech and they'll tell you what's going on. Good luck and let us know what you find out!

 

[powerstroke444e]

Is it just me or are people scared to use the truck as it was made to be used??? 4,000 rpm is not near red line. When hauling big loads up grades you will need to keep the truck in the power band which with most gas burners is over 4,500 rpms.

I would say most of my trucks get near red line on a regular on ramp. Thats how they are built if you treat it like a little old grandma and pamper it and dogging the engine I feel that does more harm than good. I feel everything should be ran wide open, it keeps the coolent flowing and the fan pulling more air and in the lower gear it is easier for the truck engine and tranny(IE more leverage). I say run it like you rented it.

 

[Ryan03]

Is it just me or are people scared to use the truck as it was made to be used??? 4,000 rpm is not near red line. When hauling big loads up grades you will need to keep the truck in the power band which with most gas burners is over 4,500 rpms.

I would say most of my trucks get near red line on a regular on ramp. Thats how they are built if you treat it like a little old grandma and pamper it and dogging the engine I feel that does more harm than good. I feel everything should be ran wide open, it keeps the coolent flowing and the fan pulling more air and in the lower gear it is easier for the truck engine and tranny(IE more leverage). I say run it like you rented it.

I agree with you to for the most part, as I drive all of my vehicles on the agressive side. That being said, I would not want to spin that 496 cube engine with its 4.250 stroke at 4500 rpms for 3 miles up a mountain when it gets some miles on it, say 140 or 150k. It would not bother me a bit with a 40k mi truck though, other than having to listen to it scream for an extended period of time.

 

[FlaDon]

Is it just me or are people scared to use the truck as it was made to be used??? 4,000 rpm is not near red line. When hauling big loads up grades you will need to keep the truck in the power band which with most gas burners is over 4,500 rpms.

I would say most of my trucks get near red line on a regular on ramp. Thats how they are built if you treat it like a little old grandma and pamper it and dogging the engine I feel that does more harm than good. I feel everything should be ran wide open, it keeps the coolent flowing and the fan pulling more air and in the lower gear it is easier for the truck engine and tranny(IE more leverage). I say run it like you rented it.

No need to beat up on an engine when the peak torque is at 3200 RPM. Or 65 MPH in 4th gear unlocked. If the load doesn't require it, the Ally will drop down to 2800 locked and RUN up the hill at 65 MPH. But I do go thru the gears at the points where it goes from peak HP to peak Torque at each shift. The HP point is 4500 RPM, Torque is 3200. Factory redline on the 8.1L/496 is 5000 RPM.

Longest life on an engine comes when they are run at about 3/4 load-3/4factory redline.

 

[Eagleview]

Horsepower sells , Torque propels .

Run them at peak Torque .