Allison 6 Speed Automatic

guest · Feb 14, 2007

My wife & I now have a new truck (straight - 33,000gvw) with our first automatic transmission (she absolutely hates it). We need information on the operation of this transmission and of course the saleman could offer no help and there is no manual that I can find. So, what do we do? We need to know how to drive on snow & ice, how to downshift on a steep down grade, etc. If someone knows where I can get a manual or can offer some help we would be most appreciative.
Stay safe, warm & dry!!!

TeamCaffee · Feb 14, 2007

We have a six speed automatic with out having any engine brake to back it up. We must be doing ok we have over 300,000 miles on our truck and our brakes really look good. Not much wear on them. We have been over just about every pass in the United States in all weather with and without chains. Our transmission is always in 6th gear and we have had no problems. The transmission automatically shifts down when climbing or going slow down hills. In snow are ice no different then a car we drive slow. We love our automatic but on the next truck, as we all say, we will have an engine brake.

LDB · Feb 14, 2007

I've got that transmission. My truck has an engine brake that was factory set for an 80k t/t rig so flipping it on is like hooking the wire on an aircraft carrier. The only thing I don't like about it is how high it revs when applied. It will downshift and wind to about 2400 rpm. If I didn't have that engine brake my suggestion would be to slow to the desired speed by the top of the grade and use the down arrow button to shift down to whatever gear you felt appropriate for the grade. Basically you think of pushing the up/down arrow buttons as the equivalent of a double clutch shift in a manual transmission truck. I believe it will not allow the truck to shift if the rpm in the new gear would damage the engine so in theory you could push the down arrow button from 6 to 2 and it would only downshift as your speed slowed. I'm not brave enough to test that theory though. If/when I do move out of 6 I do it one step at a time. The first time you are in purgatory traffic, uh.. Chicago traffic, you'll love that transmission or at least your left leg will.

Leo Bricker, 73's K5LDB, OOIDA Life Member 677319
Owner, Panther trucks 5508, 5509, 5641
Highway Watch Participant, Truckerbuddy
EO Forum Moderator
----------
Support the entire Constitution, not just the parts you like.

bludragon13 · Feb 14, 2007

We have an Allision with engine brake , it has three settings and works great, been over every pass from Donners to the those in W Virgina. You don't have to do anything hence Automatic it will down shift as needed and as stated the heavy traffic will save your left leg.Took some razzing at first but after a few months those who scoffed were saying their left legs felt twice their size after all the down and up shifting in the rockies and their next truck would have the Allision. Do get the 5000 mile filter change and go to Allision dealer to do it- good one in Grand Rapids Mi.

SHARP327 · Feb 15, 2007

If you have synthetic trans fluid in it you'll need to change out the filters the 1st. 75k and top off the fluid then when it reaches 150k you'll need to change all the fluid and both filters and at 225k it's back to just changing out the filters again and so on and so on.

Come to think of it mine is due pretty soon.

simon says · Feb 15, 2007

I upgraded to a new Pacbrake on my Eaton-Fuller Roadranger, but the principle is the same. My old one had a broken bracket and Pacbrake basically charged me only for the upgrade ($212) and I installed it easily. Great deal- even out of warranty. I kept the old cylinder in case I need it.
This model really slows down the truck in the lower ranges/rpm's down to 800, so it will slow you down from high speed all the way to 800 rpm where it falls off. I know from reading the Pacbrake brochure, you can get one for an Allison that works automatically as others said. A throttle equipped unit should be installed by a pro.

Beyond that, the Allison should work fine, it will downshift on its own. I wouldn't worry too much, but I would slow the truck before a sever downgrade and lock it into manual mode and downshift as necessary. Happy traveling!

Mudflap · Feb 17, 2007

They do a very stupid thing on engine brakes with the smaller Allison automatics that does not work like a real engine brake on a big truck. It couples an exhaust restrictor with downshifting the auto tranny a gear. First it downshifts, revving the engine high, then the exhaust restrictor comes on. This system beats the hell out of the engine, the tranny, and especially anything coupled to the belts of the engine as it continuously varies the engine RPM up and down from 500 to 800 RPM. The latest example of this system I came across with a CAT C7 on an RV broke all 4 of the bolts that held the fan hub to the engine, throwing the fan, the pulley, and belt in to the radiator. In my opinion this system is not only a joke for an engine brake, it is dangerous and will leave the truck totally disabled if it fails. Mudflap

LDB · Feb 17, 2007

Mine doesn't vary the rpm. It does something with the air system because I can hear the sound when the valve opens or closes. It shifts down to a high rpm and really drags the speed down and then shift down again to high rpm and repeats. It works similarly to the engine brake on my ISX except for the shifting down on it's own part. I just wish it didn't rev as high as it does and also had at least a second setting that was about half capacity. When this thing is empty and I flip it on it's like hitting the number 2 wire on a carrier.

Leo Bricker, 73's K5LDB, OOIDA Life Member 677319
Owner, Panther trucks 5508, 5509, 5641
Highway Watch Participant, Truckerbuddy
EO Forum Moderator
----------
Support the entire Constitution, not just the parts you like.