Auto trans runs, won't shift...

[EODguyJake]

Here is how it happened, ripped from the engine 911 thread

"OK, so I got of the highway coming home, and I was playing with the tow/haul mode. After I stopped at the post office, I notice my tranny was shifting funny. Got back to the house, and something was definately wrong. When the truck would try and shift out of first, the whole thing would shake, shudder, and not shift. I would hit the tow/haul button, and the engine would change sounds (quieter), but the light wouldn't come on. I reset the HyperPAC to stock, and tried it again. This time, it still wouldn't shift, and the tow/haul light wouldn't go off, so I turned the truck off to try and start it again, and the think won't hit a lick. Everything comes on, but the motor won't even try to crank. I have the battery cables disconnected right now trying to reset it, but I don't know if that will work. Anyone have a clue? I can PM my number if you wanna talk to me about it."

The truck has started, but if I try to pull a hill, it just shakes and shudders. I will drive, but it won't shift. I've had it up to about 45, and it was just over 2200rpm. I have tried manually shifting the tranny myself, but no matter what gear I put it in while driving, nothing changes. Again, if you want to call me, I will PM my number. For what it's worth, the truck only has 29K miles, and I run that HyperPAC, which isn't an extreme tuner by any means.

[EODguyJake]

OK, after disconnecting both batteries, the thing is running normal. I would still like to see if anyone knows WTF that was all about? Also, would you take it in and have it looked at, or not? I run the risk of the dealer discovering my tuner, even if I do yank it out of there. But, if there is a bigger problem, I need to get it fixed. This is the second time in about a month I've had my tranny doing hokey chit. The first time, if I reset the truck to stock, it quit. But, if I cranked the computer up, it would start it again. At the advice of Hypertech, I unplugged it for a week, and it went back to normal (it was doing something different at that point) even with the tuner. Obviously, this time resetting to stock didn't fix it, which tells me it's a truck problem, not a tuner problem. Any7 insight would be great.

[mschn99]

Sounds like a possible sticking shift solenoid. When was the last time it was serviced?? PM me your vin so i can run oasis and make sure it doesnt have the trans recall still open as well...