looking for some help in regards to how the allison shifts and locks the TC - in normal mode driving down the road, will it lock right before shifting and then right after ?? and what gears will it do this in ? I know 4th and 5th lock up but then if you nail it in either gear will it unlock then lock again ?? ie, o/d locked out, in 4th gear locked down the road, and nail it - will it unlock then lock back up ? and on the freeway with 5th gear locked, nail it, will it unlock then lock back up ??

Shiftlockunlockshiftlockoutdownshift.............. ..WTF! http://www.dieselplace.com/forum/smileys/Geek.gif


You asked a whole lot of questions. http://www.dieselplace.com/forum/smileys/Clown.gif


Here ya go. In normal mode it will shift up through the gears until it reaches 4th, then it begins locking the TC under light load conditions, add more load (throttle) and it will unlock and/or downshift to deal with the load. In T/H mode it locks 2-5 and will stay locked under a heavier load condition than in normal mode. But if you stomp on it, it will unlock and/or downshift to provide the appropriate power to the rear wheels. The tow mode really just changes the point at which it locks and unlocks the TC, and allows a shift, everything else is the same.


i.e 5th gear 55 mph T/H on. Slowly roll into the throttle.......it will stay locked and not down shift. But if you spike it, it will downshift to 4th locked and run up and shift into 5th locked.


Normal mode same situation it will unlock in 5th, then downshift to 4th,(if you nailed it) lock.......then shift up to 5th locked.


Did that answer your questions?

LOL http://www.dieselplace.com/forum/smileys/HiHi.gif - that did answer my question, very well actually and is kind of what I thought but wasnt sure. Thanks for the feedback and reading thru all my babble

Tom


When you are in O/D, WOT, your converter will lock at the top of 2nd. It will release and lock again in 3rd. Sometimes stay locked through 4th. I did a bunch of testing with Diesel Tech on his LLY.


mike

thanks mike, that makes sense to and is kind of what i thought was the case as i have been listening/feeling the alli and playing around with the TTS / Edge and read Koopdaddy's topic about getting the stack right and it hit me that if it was shifting as i thought per above and like you explained that he might be right, and defueling on locked shifts may indeed stop the turbo from barking... - i have never really run around too long with defueling on so i figured i would try it out and see what happens.

Tom


Get my buddy Nick to hook up his Tech 2 on your truck and have him watch when it locks and unlocks while in O/D. It takes 2 people to do this test. Steve Cole and I did this test for over an hour, he drove, and I never took my eyes off the scanner. You will learn some new stuff,


mike