van will drive fine until i stop,when i try to go forward tranny slips.Then ill shift to neutral and tap on the gas just to get a little rpm and shift back to drive,and it will drive with no problem.It will do it only when i stop.What can it be?check oil level is fine

 

Sounds like the forward clutch is giving up. Have you tried and filter and fluid change? It may be too late to do any help, but it's all you can really do without yanking it and see shaking it upside down to see what broke.