Harsh Shifting Question?

[XAM-D]

2002 D/A pulling 13,000/14,000 lbs. Juice 4.31 on level 2 in tow haul mode. Truck sometimes shifts real hard between 2nd and 3rd when excellerating(not really hard excell). Seems like it misses the gear, then seconds later it catches and jerks forward really hard. Doesn't happen all the time but usually 2 or 3 times on 500/1000 mile trip. Does the juice have an update for this problem, is the truck just defueling after a slip is detected, or is it something more serious. Its going in tommorrow for other services but you know they'll say they can't recreate the problem.

[sdaver]

I HAVE THE HOT VERSION OF THE SAME JUICE AND IT HAS HAPPENED A FEW TIMES I THOUGHT IT SEEMED TO HAPPEN MORE AFTER I SHIFTED FROM TOW HAUL BACK TO NORMAL. IT SEEMS TO HAPPEN WITH LIGHT TO MODERATE ACCELERATION. NO OTHER COMPLAINTS WITH JUICE. THOUGHT I WOULD WAIT A WHILE FOR A UPDATE. ON THE OTHER HAND MY MOTOR HAS NEVER BEEN THIS QUIET AND SMOOTH..... :D DAVE

[hoot]

When I turm my propane off, my truck bangs gears. It's cause the trans is always changing it's parameters to your driving habits. It really gets confused if you always do things different. Basically you get ahead of it. If you drive at one power level for a while then switch, the trans still thinks you are at the higher power level so it shifts tighter.

The delay you are experiencing is what we call defueling between shifts. It's normal and gets exaggerated when more power is applied.

I believe some boxes control it a little more than others?

Your hard shifts between 2nd and 3rd are probably caused by the extra power. It may go away as the trans learns. But then it could create strange shifting when you go back to normal levels.

I'd like to see an aftermarket TCM that addresses some of this stuff. Maybe a two stage TCM program that saves two sets of settings. Normal and performance. Too much going on with the engine but not much to address the trans.

[ 11-13-2002: Message edited by: hoot ]</p>

[hdmax(mike)]

My truck does that once in awhile if I give it a little throttle just as it is about to down shift into 2nd at about 20-25 mph. And this is without any juice.

[Kennedy]

Update your Juice while you have it off. I think you will like the end result!

[Brandenburg]

John, when you said to update now because you'll like the final result, are you suggesting an update to the hot version or are you saying that the version they have out now is a somewhat final version and has addressed all the known issues?

[Kennedy]

I'm just saying that 4.31 std. isn't on my short list...

[ 11-13-2002: Message edited by: kennedy ]</p>