hi, My 2001 3500 starts and runs fine in park and neutral but put in any other drive or reverse gear and everything shuts off instantly. There is no "sputter" just instant off.
This problem started intermittently a few days ago where I could rev it up a bit and pop it into a drive gear but now nothing. It seems to be electrical- with engine running smooth in park I take the shifter very quickly past reverse to into neutral and engine stays running smooth BUT the instant shifter passes reverse everything electric goes out for just an instant- any lights, guages etc.. It's like whatever sensor won't let you start engine in gear now won't let it run in gear either.

Thanks in advance. Any ideas would be greatly appreciated.

i jusf finished a road trip thru some very mountainous terrain. Going into the mountains tranny was good in that I would speed up to like 75 downhill for enough momentum to top the next crest at about 55 in over drive. On the longer climbs I had to pop it out of OD but could still make the top going about 50. As the mountains got steeper I really had to struggle to make the tops at even 45. This is a 10 foot tall high top 3500 maxi with a lot of weight. By the time I was leaving these hills I had to travel late at night because not only was I having to drop down to 2nd and even 1st gear I could barely make the tops at 20 mph and couldn't even get up to 60 going down the grades. Downhill if I tried to go faster it would downshift??. The last leg of the trip was thru flat Florida and the fastest I could get the van to go was 50 and even a small rise like going over another road would slow me down to about 40.

I thought that that and my start up problems were 2 different things but maybe not. I actually didn't make it all the way home ending up in a rest area 300 miles short where I am now. I put a new ignition switch in today which didn't solve anything. Does that other hill climb stuff sound like it could have been caused by or is symptoms of a locked up torque converter? Also what is the fix for such a lock up a new TC?
Read some bad TC symptoms and I had some- shuddering and rattling sounds.

thanks.

So yesterday I had it towed to a shop from a rest area on the highway after sitting for 4 days waiting for my one time 200 mile tow to kick in from AAA. To get it on the flatbed we pushed the van backwards 20 feet engine running in neutral. Tow driver asked me to line it up a little better not understanding it wouldn't run in gear. What the heck- I put it in gear and somehow after pushing it IT RAN ???. Even idling in nuetral I hear a rattling from the front of the tranny. Still took to shop with diagnosis later today. My main reason for this description is to ask if the shop drops the bomb "you need a new tranny" does that sound right?
Thanks.

Tranny shop said everything ok with tranny but that cat. converter was clogged very badly and rattling. New cat converter going in tommorow ($300) and hopefully that will fix it. As far as instant engine cut off in any drive gear- which was the case a couple days ago but not now- I'm hoping some sensor somewhere was telling PCM not to let the van drive anywhere cause of clogged cat.

New cat. converter installed and the engine power issue is 100% fixed with tech saying there had been severe cloggage in old CC. Drove 15 miles back home from the shop making a few stops restarting the engine several times.
Now 6 hours later back to the same condition as thread title; "P and N good but R, D, 2 and 1 cutoff engine". This is after tranny shop found no problems. Engine idles smooth in P & N and "revs up" well. Thing is when engine cuts off with shift to any drive gear it is not a stall but an immediate electric shut down. Apparently I had 2 original problems with one remaining which remaining may or may not have been caused by the other (CC).
Any other ideas??
Thanks