Stuck in neutral?

renolaw · October 17, 2013

2001 2500HD with alison 1000. Warn M12000 winch with dual batteries. Assisted in the recovery of a jeep that rolled into a deep gully. Hard pulling and amp draw at about 10 degrees side hill-- near level. . Truck in park and ebrake fully engaged. Hard pull really put load on system-- ran up RPMs to help recover some juice. At one point winch stopped working due to insufficient power. (should have used the snatch block). Winching force actually pulled truck sideways about 4'.

Eventually got him out and was time to go. Put truck into drive and....nothing. Reverse...nothing. Uh oh. Rescue rig needs help. Another vehicle pilled me onto level pavement and turn off engine. Let it sit for about 5 minutes and upon start up, all is normal.

Any explanation why/how a period of high RPMS in park will neutralize the tranny? Or did the T-case go into a fit?

thanks

ujtruck · October 17, 2013

many be abuse mode kicked in ?

I would like to know the answer too.

Prokopchuk_9 · October 18, 2013

Sounds like Limp mode or something. But can't e since you weren't even moving...maybe it just got mad at you for a second lol

gmtech4 · October 18, 2013

the transmission saw a ratio difference when it was grunting ,possibly slipping ,,,they dont like that and WILL trip the code and default to "you are not going to get me to move " message on the dic ,,,,,upon the restart the TCM did not see anything abormal and away ya went

that is what happened ,,,,you can pull the code out of the TCM if ya want for giggles ,,,,,but it will eventually clear itself ,,,the ECM will also have the p0700 "hi this is the TCM ,i have a wee problem goin on here" code

dont do that again ,ive seen allison input shafts and C1 clutch packs "themally coupled" (burnt,cooked,forked because of getting stuck,it had 16K km on it ,,,we warranted that bad boy ,,,,,no abuse at all,lmao

ujtruck · October 18, 2013

hah thats good to know, thanks

renolaw · October 18, 2013

here in thye winter our group is called out to recover stuck vehicles and the 2500 is used for easier jobs. I have a built CJ for the back country stuff. Never done this before.

Transmission in park but revving the RPMs to wind the alt to put back some juice to the dual batteries while winching. The draw this time was so great even temporarily killed the 2 meter ham radio. killed power but came right back on.

another time we were on 3 week vacation and upon return home the chevy did the same thing, but from sitting for 20 days. Would not back out of driveway. Let it idlefor 5 minutes then it engaged into gear.

Also notice sometimes when slowing down approaching a red light but light goes green before I come to a full stop. Give it gas to go and RPMs jump, nothing happens like its in neutral, them BAM it catches and off we go.