2002 /44,000 mile Trans Failure

I have a new problem with my 2002 GMC 6.5L Turbo Diesel 3500 Cut-a-way van. (3500 Series Van with Stahl Utility Body Dually)

Yesterday van shifts like someone installed a shift kit in it...bangs gears and locks up early on OD.

Today... I come off the highway, stop at the end of ramp, wait for cars to go by, try to take off and feels like its in neutral....but its not.

Some fine high pitched noises and she reluctantly goes untill the next stop sign...same thing again.

First thoughts are low tranny fluid....but when I pulled the dipstick, it had plenty of trans fluid....But!! ..it was grey and smelled burnt.

This van is maintained religiously every 5000 miles, it has never towed anything (has no trailer hitch) never plowed..and carried about 8000 lbs of weight all the time.

Any idea's?

Thanks
JLC

that is a problem with chevys there are junk get rid of it and if you have to get another chevy get one with a stick same with a dodge weak trannies unless they have a stick in them my buddy dad he is like fifty has a 2004 chevy 3500 with a gasser and about 10000miles the transfercase took a crap and it was the first time he but it in fourwheel drive cause of one foot of snow