Allison 5sp: Hit lockup switch lock button, loud bang, limp mode, codes, strange noises....
- Thread starter thunder550
- Start date
I was not having lockup issues other than it wouldn't lock up until 3rd gear.
Actually just a couple days ago I had an issue where I lost connection with the rear speed sensor when I took off from a light. I was wide open and probably into 3rd gear when my ABS and brake lights came on, speedo dropped out. Turned out to be a bent pin where the speed sensor extension connector in the transfer case harness connects to the trans harness. I did not have continuity from the VSS to the TCM on the green/black wire. Last time the harnesses were touched was when I had Copperhead install your springs and swap my converter out at the end of April, but I'm not sure if they separated that connector or not. It could have been that way for a long time. Ever since I put the truck together in 2013 I have had an occasional issue where I get the ABS/Brake lights on until the truck starts moving, then they have always gone out. Last week was the first time it happened while I was actually driving.
Anyway, I fixed that pin last week on Thursday or Friday I think. This was the first time I had really driven it since then.
This was one of your major problems. The feedback from the speed sensors to the TCM was all wrong and the TCM did not know what to do. The converter should have been locked in 2nd as the TCM was programmed to see it locked at WOT. The TCM was in limbo and there was a massive tie up.
Thanks for chatting with me Mike, I'll call and set up an appointment when I'm ready to bring the truck out to you. Probably be a month or so before I can make it out there.
you know he has an LML and trailer specifically for the 1500, right? :roflmao:
Shouldn't you be on a train going somewhere?:roflmao::hug:
I don't think I wanna go back to work just yet
Shhh, I think he was offering to pay for the fuel. I'm going to see if I can trick him into paying for the rebuild next :woott:
I started the truck up today to move it out of the garage and the speedo ran up to about 7 or 8 mph while the truck was in park. It was making that grinding sound while in park. As soon as I put it in drive the speedo went back to 0 and the grinding sound stopped. I thought the VSS was on the tcase output shaft...how did it register speed when I was in park and not moving?
Would the park pawl (or whatever it engages) and the transfer case would both have to be broken to have speed registering while in park? I can't make sense of it.
Never seen a parking pawl busted on the Alli. You must be getting a reading off the turbine speed sensor. If the Alli is in limp and stuck in 3rd gear; maybe it's possible. I have not seen this before.