An Allison Brain Fart?

[56Nomad]

On several occasions my transmission seems to have
been unable to make up it

[Turbo Al]

I sure hope it's normal happened for the first time this week with about 16,000 miles on the clock.

[motovet]

I have had that happen at least a couple dozen times in my 14,500 mi. Sometimes it is slight and other times it sounds and feels like something could come apart. As long as nothing does I will continue to take this strange phenomenon for granted as I have gotten kind of used to it. I will say it has happened more often with the added power.

[James S]

Hey Folks,

I think I know why you are having this problem. I have experienced this myself in a vehicle with the Alison 1000 transmission. The computer in the transmission, "learns" how the vehicle is being driven. If the vehicle is being driven rather leisurely, the computer controlling the transmission, will shift it "leisurely". If the driver's driving pattern suddenly changes, the computer will take a few shifts, to adjust to the new driving pattern. If you are going slow the transmission will be thinking,
"okay, we are going nice and slow, so I will down shift, nice and gently". When the driver accelerates, the transmission will panic and think,
"Wholey ****, you want to go fast! Why didn't you tell me, I wasn't ready to shift hard and fast!!" You get my slightly exagerated point. The transmission works best when the driving style is constant and does NOT change. Therefore, when it changes, it takes a shift or two to adjust. Now, this is what I have read and been told, and witnessed, but if it persists, check with your dealer. Maybe I am not aware of something else. If you find out anything, let us all know.

James

[Arnie]

I hate it when computers think...... :mad:

[ 09-06-2002: Message edited by: Arnie ]</p>

[TBC]

What you are talking about seems to be the same thing my truck has done. It seems to be worst when I am driving slow like in a parking lot and ease down on throttle and then let off it seems to want to shift at a very slow speed. I began to notice that it would do this after I had been driving slowly and manuvering, etc at a slow speed. Recently I have been driving it a little harder every chance I get and trying not to do the slow easy acceleration as much and it seems to like that better. I think James has hit the nail on the head. Someone on the site tells everyone to drive it like you stole it. I think he may be close to right as far as the smart trans is concerned.

[MNBowTie]

Hey everybody has don this a couple of times, only I was towing at the time. I had the TCM re-flash for this issue and the shifty business. So, for I'm pleased with the re-flash, however, I now get an abrupt down shift from 2-1. I still recommend the re-flash although.

[NEW2DMAX]

Did it to me one time while pulling a empty 18' stock trailer, scared the crap out of me. Called the service dept and they said get it to us asap for a computer upgrade. Got the upgrade and 3,000 miles later 1,400 of that pulling a travel trailer to Colorado and have never experienced the problem again!

[johns]

Mine does the same thing. I have 9100 miles on it. The only pattern i think I have is that when I go up an incline and let the truck coast to a stop rather than stepping on the brake pedal. When I step on the accelerator, it seems like the trans is still in 2nd gear and then slams into 1st. Doesn't seem to do it if i step on the brake pedal.

Could there be a signal from the computer that doesn't get sent to the trans to shift to 1st if I don't step on the brake pedal?

[bhinrichs]

My truck does this only if I drive 2 footed. It seems that if you keep on the pedal while using the brake (like coming to a stop sign going up hill), it doesn't seem to shift to 1st at the stop. Then when you take off, it seems to dog in 2nd for a second then goes to first and bites.


Bert