I've had some folks tell me not to idle for long periods with the Allison in gear because the Duramax has so much low end torque it's hard on the Allison. I've been in some cities where the stop lights can run 2 or 3 minutes, is this too long and should I kick it into neutral?? Also the traffic jams can stop you in place for 5 minutes or so, is that too long? I've been playing safe and kicking into neutral, am I being overly cautious? Is it causing more harm shifting it back from drive to neutral and back all the time?

I think you're being overly cautious.

I think shifting back and forth from neutral is worse than idling in gear. That's what the torque converter's for.

i think shifting back and forth from neutral is worse than idling in gear. That's what the torque converter's for. x2

There is a warning in the driver's manual about prolonged idling in drive. Not to go over 5 min. if I recall,something about lack of fluid movement .:eek:

Idling in gear will create heat in the torque converter. If there isn't enough airflow going over the cooler your trans could possibly overheat. If you have to idle for long periods, kicking to neutral is a good way to keep the temps down. This is especially true for built transmissions with tighter converters.

Modulated Main in the '04 up transmissions helps to alleviate this by lowering main pressure at idle.

What braden says.....

Just watch your gauge though in stop and go traffic or sitting for long periods. If she starts getting toasty then kick her into N. and if she is getting toasty then driving in TH should help her run a tad cooler.

Even in with my 03 idling in gear for extended periods never seemed to get the temps real outa line.....get em warmer no doubt. Maybe CA traffic or something would be different.....

Yes to Brayden's comment. "Modulated Main in the '04 up transmissions helps to alleviate this by lowering main pressure at idle."

Modulated main feature in the MY04's and later years lowers main pressure at idle AND sends additional oil flow through the converter and cooler to keep converter temperatures down in drive idle stall conditions.

No more than 5 minutes in gear as per the g.m. allison trans course i took....