I have noticed while viewing my Juice Monitor, my tranny when cruising in 5th gear, will unlock and lock the torque converter on small grades and whenever I apply throttle. Is this normal? Also when the tranny is cold, it will take awhile for it to lock up in 5th.


I never really noticed any of this until I programmed the monitor to show gear selection.

I have the same problem, general concensus is the converter is dying.

Really? You mean the clutch itself or the actuator?


What causes this?

I don't think it's a converter problem. That is normal operation. The converter will delay locking until transmission fluid temperature is up. I saw mine stay unlocked for as much as 8 miles of my 10 mile morning commute on occasion. The converter will also unlock in expectation of a shift if it sees throttle position go up with no change in speed. It will also unlock around 50 mph in anticipation of a programmed downshift to 4th that happens around 48 mph. Normal operation - not DYING - don't be so paranoid!http://www.dieselplace.com/forum/smileys/Approve.gif

any type of acceleration in 5th and the converter unlocks and will not lock again until I am off of the throttle so yes the converter is DYING in my case.

Carbon04, have you had the latest reflashes performed on your TCM? This sounds suspiciously like the "shift business/reduce downshifting" issue. I was also going to say that I haven't seen any converter failures (other than loose bolts) on any truck that hasn't been seriously raced or flogged - but I see you have a 125 Juice in your sig.http://www.dieselplace.com/forum/smileys/Embarrased.gif Mainemax, however, is showing absolutely normal TC actions.

Wouldn't think an '04 model would need a software upgrade/fix intended for the '01/'02 Allisons.

I drive the truck, not baby it. The 125 juice is more than enough power to kill the converter. I have probably 50+ 1/4 mile passes with the truck.I have literally one of the last LB7 DMAX's to roll off the line. It was built the last week in Dec 03. So there are no software upgrades as of now.

Thanks guys for the info, I feel better knowing this is normal and no cause for alarm. I bought the truck used, so I am always on edge about anything that seems abnormal.


Thanks again