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Discussion Starter #1
Happy Holidays,

I have a towing question boys......
Do any of you Tow w/o Tow/Haul???

I will be pulling a 6500 - 7000 lb.travel trailer loaded...That will be full weight with occupants, dog, food, fuel, etc.

My question is with the Allison Transmission do I have to go to Tow/haul mode or can I just tow in (D), Drive????

Will any harm come to the Allison? I'm talking relatively mild towing ground, fairly flat w/ few hills.

Would it be searching for lower gears all the time or would it act ok & not overheat etc????

Only got 350 miles on it now & too cold up here anyway to play, so I'm looking for advice.

Thanks, Paul
 

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Hi Paul, I have 1400 miles on mine and am still breaking in the rear axle. the factory says dont tow for the first 500 miles, and then at 50 mph for the first 500 towing. Use tow haul mode for the lower speeds so you don't lug the engine, 4th will give 2050 for 50 mph. Once the rear end has seasoned a bit to allow higher continuous speeds the T/H mode is not needed as long as you are not searching for gears or downshifting from OD a lot. You will love the auto braking the T/H provides. Enjoy...
 

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On the 03 year model you can push in on the tow haul mode button and hold it for 5 seconds. This will lock out overdrive. Just to give you some more options. Not sure if you can do this with the 04's.
 

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I would put it in o/d and go, use the tow/haul if you wish, I mainly use it for grade breaking. It does seem to pull a bit better also in t/h


Unless your really heavy and your downshifting alot, dont worry about locking out o/d
 

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I always leave my truck in Tow/haul when my trailers are following me.


Sometimes I forget to push the button after refueling on long trips because it goes off when you shut the truck off.....so now I just leave the truck running when refueling.
 

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Discussion Starter #6

Thanks guys,

I'm "learnin".......I am glad for the help....

Thanks, Paul
 

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I have found that while towing with the cruise control on the Allison will have a tendency to downshift often on any kind of a grade. This is because the Allison is trying to keep you going at exactly the same speed it was set on. The best way I have found to combat this is if you are coming up on a moderate grade, take the cruise off and keep just enough pedal to where it doesn't downshift. You can allow yourself to loose 3-5 mph and still keep it in high gear. It takes a little practice, but it sure beats downshifting all the time. Not everyone will have to do this, but I tow a 16,500lb 5er.
 

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Towing aprx. 5K to 6K lbs, I only use T/H mode in stop & go or to use the grade braking. When in cruise control and coming to a grade, I'll take it out and if needed, hit the lock out to gain some Rs, (that prevents the auto-downshift to 3K). Because I'm not real heavy, I don't use T/H out of traffic as I don't want to spin the motor that fast...it has plenty of pull.
 

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I pull 2 different loads, the heaviest (14.500# trailer) I use the T/H mode until I get to hiway speed then click it off. When I get to the bottom of big climbs, I hit the T/H first and then O/D lockout so I decide when to increase the rpm. As far as the grade braking I can barely see much difference with the T/H on or off. The grade breaking seems to work very well in either mode. Cruise Control is almost always on. I just help out with punching a button now and then. Besides, it kicks out when you tap the brakes to engage the grade breaking. Keep one eye on the transmission Temp, engine temp, EGTs, and the other on the traffic that you will be passing on your way up the hill!!!
 

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Mitchagain...


FWIW - Grade braking w/o T/H mode should only engage in 5th and 4th. In T/H mode, it should engage down to 2nd, (I think I have that right). So, in high gear you probably won't feel much of a difference.
 

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Trip, I could be wrong, but in a long twisting downhill grade with lots of switchbacks and I am pretty certain that w/o TH engaged (I was unloaded and no trailer) that the grade braking was working down to 2nd. I am very certain that it worked down to 3rd, because it has done it several times.


Grade Braking is the best thing going since sliced bread!
 

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Mitchagain, I can feel some holdback w/o TH engage down to second. But, it is extremely minimized. Almost like a real strong hold-back tranny. I can hear it and feel it downshift w/o a load, but it is nothing like when its in TH mode. That is entirely different. The grade braking is maximized and almost throws you forward if your Rs are up, and it seems to downshift sooner. I experience max type of grade braking w/o TH mode from 5th to 4th. In TH mode, I get it down to 2nd. Someone else jump in here...maybe it's just my truck? I agree with you Mitchagain, it is fantastic!
 

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Hello All , the part you missed is that in th mode the torque convertor is locked up in 2nd thru 5th gear so the transmission acts like down shifting a standard . When not in th mode you get convertor slip so barely note the slow down . Because of the high compression of the diesel you get great slow down in th mode .
 

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Discussion Starter #14
Thanks Guys,

You words make it a lot easier.....

Love this Big Black Toy!!!


Two Dogs
 
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