tow haul question

fireshots4 · August 28, 2003

We had a 02 2500HD with a 6.0L which we pulled a 28' 5th wheel with. In this truck when you put it into tow haul it would switch into overdrive if you let up on the gas just a little or went down a hill. We weren't impressed with the way it pulled through the mountains so we upgraded to the 03 2500HD Dmax. Thats a hole other story. My question is this with the 03 in tow haul it does not shift into overdrive that we have found. That being the case why do the have the overdrive lock out if you push the botton on the shift lever again? We have done only limited pulles thus far so I don't know if it will shift into overdrive on long highway tows. It seems strange to have a overdrive lock out if tow haul does the same thing. Is it supposed to shift into overdrive in tow haul as our 02 did?

BlackSilver · August 28, 2003

It will shift into overdrive, but only at highway speed (I think the gate is around 62MPH if I remember correctly). Did your dealer give you a video about the Allison? It does a pretty good job of explaining.

Hacksaw Hilliard · August 29, 2003

I know mine has shifted into overdrive when towing my 12,000 5th wheel. Usually happens around 65mph on level roads or going downhill.

ShortCrew · August 29, 2003

When I bought my truck, the dealer told me that tow/haul changed the lockup characteristics of the torque converter in 2nd and 3rd gear. I think it locks them at lower RPM's. A locked converter = lower tranny temps.

f7_ditch_jumper · August 29, 2003

It will shift into overdrive, but only at highway speed (I think the gate is around 62MPH if I remember correctly). Did your dealer give you a video about the Allison? It does a pretty good job of explaining.

THe allison will use 5th gear in t/h @ around 55mph if use start to drive easy. Using the cruise control is the best for that trans.

BlackSilver · August 30, 2003

6.0 doesnt come with the allison. He should of got the allison

Read his message again. He traded his 6.0 for an 03 DMax/Alli, and now he has some questions about the Allison t/h.

f7_ditch_jumper · August 30, 2003

my bad. I love the alli for towing. Keep in mine there is a "break in" time for that alli until it gets the shift timings down pat.

fireshots4 · August 31, 2003

Thanks for the replies. I do not have over 500 miles towing so I have not had it that fast yet. I will see what happens when I can actually get it out and open it up on the expreesway.

Thanks again

By the way Blacksilver I think you have my camper in your drive way is that a 281EFS?