The babying the trans is really only an issue with the old style transmissions that use a cable for the line rise.Chryslers in particular by design have very long shift overlaps at light throttle,this is what kills them,you cannot slip a chrysler auto light throttling it pushing snow,its just not going to happen.You will overheat it eventually if you "tractor" snow at slow speeds at or under the stall speed of the TC.You can slip it if you've modified the engine,and allow the stock convertor to lock up and roll into the throttle gently,but this can only be done at higher speeds than most of us plow at(except Chris)
Apkole, using manual low takes the pressure off the one way sprag,since manual low applys the rear band,and rear clutch,the band holds the lo reverse drum.If you put it in D,the drum tries to spin backwards,but the sprag catches it the instant it trys to.To be honest with you,that rear sprag is very strong,ive never seen one fail in a 47 or 48,weve put over 400hp (40psi launches)thru them sitting still,stalling the TC with shifter in D and they never let go.We've had to build Billet shafts for the trannies,but were using the stock sprags still in the 700+Hp units.I use D to plow in my truck,i have that much faith in the rear sprag.
A shift kit can be tuned to provide positive engagement without an abrupt jolt.This process on Dodge trucks is very different from truck to truck,and unless you know the truck and the mods,its best left to someone who is good at them. Ill give you an example, a long bed excab 4x4 will shift much softer than a reg cab or a excab SWB truck all other things being equal.So you'd need to open the fill port more on a long bed.If you did the same mod to a reg cab ,the truck may jolt or drop in too hard.
Snowboy,be careful with the 4L80E in reverse, it is very weak.You want to come to a full stop with that trans,and if the pushing gets hard ,drop to low range until the load lightens a bit.You dont need to worry about babying that trans,its calibration and electronic controls are very good.
2_DJinn ,if you are sitting still for long periods of time with a fully warmed up or hot trand,than yes ,you should pop it in N too cool.Otherwise keep it in gear for short stops,and redlights unless theres a ton of them.Sitting still whips the trans fluid pretty good, the stator is sitting still(0) RPM when your stopped,and the TC is running at idle speed,so theres alot of heat generated by the TC,and it goes into the hot cooler line,and onto the radiator to get cooled off.If your plowing or have the trans real hot,sitting in gear for a long time could overheat it and cook it.Different TCs build heat at different rates,the TCs behind most small blocks buld heat slow,some TCs behind a modded diesel will build heat 2-3X as fast sitting still.Sitting still at idle,tighter TCs build heat quickly,loose ones slowly.