I just loaded my truck with the 65HP predator tune this evening. This is the first HP mod on the truck. The Allison transmission went crazy. The 3rd to 4th gear change is very erratic, and it seems to shift up and down between third and four gear about 6 six times before it decides to stay in 4th gear.

I was driving with a light foot to see how everything was going to handle the new power. I had to put it back to stock just to be able to drive it in stop and go traffic. The truck runs fine once out of 4th gear. It also seems to do fine with the 1st to 2nd gear change. I drove the truck about 10 miles in stop and go traffic to give the Alli time to "Learn" what it was doing, but it never got any better.

What's up with this? Why does the truck run like crap with a tune loaded in? I made sure to get the version 2.0 programmer, but it doesn't seem to work either.

How is everyone running this tune?-:t

if you search you will see you need to drive it and let it go through many "shift cycles" to learn itself, one guy here mentioned t ostart with the lowest tune first, then move up to the next higher, then the next and the tranny learn was alot smoother, mine still shifts abut funky on the highest tune, but i am not worried by it....good luck, andhang in there, it gets better

Start with the 40hp and run it for a few days. Take it easy...dont push it. Let the trans make its sloppy shifts. Once they clear up, up the power level one. A day or so later, do it again. The trans will learn eventually...it just takes a while to get used to the first level...the other ones are quick. I was there two weeks ago. It gets better. Mine shifts pretty decent now on 100hp. Occasionally, it screws up and lets off a weird shift...but thats "normal" for the Allison.

just leave it on the 65hp tune and drive it in a lot of stop and go situations. Also, I find it helps out if you don't baby it while its learning, just get on it and dog it out. Mine shifts as smooth as stock now.

I dogged the piss out of mine for about 15-30min. Then I parked it for a while. After that it was fine

The problem with dogging the **** out of it is that the clutches are slipping during shifts while its learning. I know I didnt want any of mine glazed, so I took it easy.

I loaded the tow tune in and drove it last night for about 20 miles of stop and go traffic. The truck drove just fine. This morning before leaving for work I loaded the 65HP tune back in. The truck did shift a little weird at first, but by the time I got to work it was almost like stock. I have been very easy on it. I hope the Alli doesn't think that's the way it will always be.

One last thing, the fuel mileage computer can't be correct any more. This morning I was showing an average freeway mileage of 27. I am wondering if the computer just uses engine load and vehicle speed to figure out mileage. The engine load is less so I guess it thinks the mileage is way up. I was showing an average of about 19.5 before loading the tune.

Thanks for all of the advice.

The Predator throws off your mileage calcs. It will never be correct with the Predator tune installed.

The Predator throws off your mileage calcs. It will never be correct with the Predator tune installed.

so i have notticed that too...ah well, who cares

The Predator throws off your mileage calcs. It will never be correct with the Predator tune installed.

I 2nd that! I have the 85 installed and have modified the tune to accept my different tire size. According to smokey, my speedo reads 4 MPH slower than I am actually going. According to my odometer and my hand calculations I am getting roughly 400-450 miles per 30 gallons. Before the lift and programer I was getting 500-550 miles per 30 gallons. If I drive around with my foot in it, which is just about always, then the mileage gets even worse.

You can play around with the tire size to get your speedo to read right. Mileage calcs though will never happen:)

I installed the Predator this weekend, started at 65hp and the tranny was really mixed up. I reinstalled the 40hp tune and it was much better. Guess it will have to learn in progressive steps. It shifts pretty well now in standard trans mode, but still shifts terrible in tow/haul. Does it have to relearn tow/haul as well?

Thanks

This is from an allison mech at allison, and its also posted on the allison FAQ.

1. Get on a flat straight road, get up to 65
2. Down shift to first and talk foot off gas, the trani will down shift automatically as the speed goes down. It won't just slam into first.
3. After it has cycled through all the gears come to a stop.
4. Apply the break, cycle the engine and do it again two more times.

What this does, it put some of the internal parameters back out to where they would be for high torque, then after time it will bring them back down to smooth things out. Some people will say it does not work, but I have used this on three different trucks going from stock to the 65 and 85 and it works pretty good.

Well After a week of driving with the 65 HP tune, tonight I finally dropped it back to the 40 HP Tow Tune. The Allison did finally learn the new power, and it was shifting fine. What I couldn't stand was the unpredictable surge in power. The truck tended to leap forward with almost no change in throttle pedal pressure. The 65HP is allot of power and maybe that is exactly what it is supposed to do, but I found myself constantly speeding up or slowing down because the truck had no steady power output.

I would love to leave the big power turned on, but I wish it were applied more smoothly. It is almost impossible to accelerate away from a stop sign the same way twice.