Can I Hurt The Allison Trans By Not Using Tow Haul?

[logfarmer]

I am pulling my 7x14 x 8'6'' high cargo trailer which weighs around 4500 lbs loaded with what I put in it. When towing with out tow haul engaged it seems to do fine and have plenty of power. It does downshift more often than when not towing but not much. The trans tempurature is below 200 degrees.

Is keeping the transmision temperature below a certain point all that is neccesary to keep the transmission safe, or can it be damaged anyway even if the temps are low enough.

In other words, do I have to use tow haul when ever I am towing of is there some kind of break point at which it should be engaged. Such as so much wieght, so large a frontal area on the trailer etc.?

Martin

[Draenor]

You will be ok, keep a watchful eye on the trans temps. All the T/H does is change the shift points better keeping the engine in the RPM sweet spot. It also help to keep the tranny in the correct gear instead of hunting around trying to find the correct one. That would generate alot of heat and heat kill transmissions. I would pull in the T/H for insurance.

[bryanhunt]

The tow/haul mode is a lot more advanced with the Allison than it is with the 4l80 and 4l60. It changes shift points, reduces hunting, downshifts for you when braking, etc.

 

In general as Draenor mentioned, tranmission temp is the killer (autos will last virtually forever if the tranny temp never gets over 200 and the fluid is replaced regularly, temp wears out the fluid which in turn allows the tranny to wear out). If you're driving along and the truck downshifts occasionally on level ground you're problably better in tow/haul. If the truck downshifts and upshifts on you while on an uphill you should be in tow/haul.

[StoneyPgh]

I can't imagine why the Allison engineers included Tow-Haul in the design if they didn't think it would enhance towing performance and prolong transmission life.

 

If you continue towing without T-H, keep us posted on how the transmission is holding up.

[logfarmer]

Duhh,

After posting the question I did a search for towing and found a lot of information. One post had a reply which said to look at the owners manual. I did that and right there in black and white it says to use the tow haul button when the vehicle and trailer wieght is at least 75% of the GCWR. I guess that answers my question. Sorry for being too lazy to look first. I think I might start in the owners manual after this.

Martin

[Haulin' 8.1]

Tow/Haul also keeps the torque converter locked in every gear except first, for lower operating temps and better compression brakeing.

 

Vernon

[Haulin' 8.1]

Hey Martin, check out Allison's FAQ page, it's full of good stuff.

 

Allison 1000 FAQ's

 

Vernon

[logfarmer]

Vernon,

Looked that Allison information over, very good and usefull. All their disclamers about the way every thing has been designed to work together as a unit made me a little concerned about getting a tune. I dont want to damage anything in the power train.

Martin

[Haulin' 8.1]

Well then they accomplished their goal, it's a scare tatic for the most part. Much of the Allison aftermarket are proven to work products. Go back to Diesel place and read some of the Allsion forums. It would be nice if the Allison TCM was more accessable but Allison as a company is very standoffish, secretive, and expensive. The only aftermarket software capable of modifying the TCM at this time is EFI Live, and it doesn't have full control yet. Also the torque characteristics of the Duramax and Vortec 8100 are different. I've yet to hear of any 8100 mods causing an Allison to fail, even supercharged.

 

It's gotten to the point with automotive performance modifications being so commonplace that the manufacturers are adopting zero tolerance with them to limit their liabilitys with warranty costs. I can't blame them as many people go out with brand new vehicles and destroy parts under warranty with performance mods and motorsport style operation then expect the manufacturer to cover their foolishness. Now GM dealers can only reflash for factory offered tire sizes etc. I've seen a few posts lately where guys had the dealer reflash their PCM then found it was "locked" meaning they could no longer access and modify the tuning. It's old news that many manufactures pay people to frequent automotive competition events in order to photo and document their late model vehicles being used. They use this information to void all warrantys on those found in competition style events. I remember reading a post about a guy with a Mitsubishi EVO who blew chunks of his transmission drag racing, so he removed the mods and has it towed to the dealer. They called him back and asked him to come in so they could show him some things. When he sits down with them they pulled out a folder full of pictures, dates and times, etc. of him racing the car. They had the plates, VIN, and his face. They gave him a letter declaring his warranty null and void, handed him an estimate on the repairs and asked him to pay for the repairs or take his car home. He cried like a girl online about it but I thought it was funny.

 

Allison/GM is trying to protect you and themselves from you. If you don't care about or have a warranty then do what you want with your stuff. Just choose what you do to your truck after carefull consideration and operate it like you have to pay any repair bills you incurr and you'll be fine.

 

Vernon