Tow-Haul Mode and Overdrive

[LuvRving]

I just finished reading an article in the May issue of Trailer Life concerning the tow-haul mode and overdrive (Page 12). This guy has a 2005 2500 diesel and the transmission and engine were overheating on mountain driving. To make a long storey short the mechanic, who went with him to reproduce the problem, told him to only use tow-haul mode when towing uphill and always use overdrive, " as the manual clearly states".

I'm probably missing something here or maybe it's the age of the truck, but my 2012 has D, 1, 2, and M as towing choices and I always use D and I always have the transmision in tow-haul mode when towing. The exhaust brake is always on when I'm towing as well. So far I've never had an overheating problem. On steep grades and on hot days the transmision guage will show about 82 degrees otherwise it's about 65 to 68. I remember my older GM vans used to have an overdrive option but I haven't seen it lately.

Am I towing my unit using the transmision properly? I've discussed this with several rvers and they do it the way that I do it.

Thanks! (The Bird comes out of storage on May 2nd. !!!!!!!!!!!!!)

[Mike Clay]

I think in our case at least the 6 speeds over drive is 6th gear. I can't speak for Dodge or Ford anymore but the Allison works like this. In normal mode in drive the torque converter does not lock up until you go 45 mph or grater until it locks in and that would be 5th gear. In tow mode the converter stays unlocked in 1st and part of 2nd. Then it locks and the shift points are changed compared to normal mode. 6th gear does not happen until you hit 65 mph. On the flats I set my cruse at 65 and it will shift to 6th on the flats.

In my older Dodges with the older transmissions the torque converter would not lock in lower gears and would cause them to overheat. Another thing people do is set the cruse and hang on over the mountains then wonder why the trans temp and water temp climb so high. I have the Edge Insight on my truck and I set alarms for boost since it seems anything over 24 lbs of boost causes heat for the trans and water. Seems to be the sweet spot for my truck and weight of trailer anyway.

The question I have is why is your tranny temp so low. In the conditions you mentioned mine would be around 125 degrees or a bit higher. Mine will not even go into tow mode until the trans temp hits 82 degrees.

I guess to sum it up is that when Im hooked up to the trailer I put it in tow mode. Remember you don't have to be the first one over the hill.

[Don Wilson]

Mike I think the reason Joe''s temps might seem lower is he probably is using Celsius temps!

I always tow in tow haul mode in my 2006 Dodge 3500 and have not had any high temps!

Don

[LuvRving]

Yes, my temps are in celsius. I made and error in my post...I was just out driving and I said I had D, M and 1 and 2. Actually it's D, M and 1....no 2.

Anyway it looks like I'm doing OK!!!!!

Man, I love this truck!

Thanks!

[Mike Clay]

sorry did not pick up on that.

[Samsbird]

I did not realize that the Allison ran so cool, the 6R110 Ford runs at 190 solo and tops out around 195 pulling.

[Mike Clay]

The warmest I have seen mine is 155 degrees.