1999 Town & Country transmission

As I was excellerating to get on an entrance ramp to the highway last week, my 1999 Town & County bogged down, the speedometer dropped to zero and the RPM needle hit 3700 although my engine wasn’t revving. Since then, it’s bogged down a few times as I was excellerating or stopping, just as the transmission is changing from 1st to 2nd or 2nd to 1st (is my guess). I’ve been very lucky, I have 136k and haven’t had any problems. I drive from a wheelchair, this van is modified with a ramp and would cost close to $50k to replace. Please help.

If the problems with the transmission only occur when the speedometer goes to zero, the whole problem is likely to be the transmission output speed sensor. It is good practice to replace the input speed sensor at the same time. Not a very expensive job. Is the “Check Engine” light on? Has the transmission fluid and filter been changed? It is absolutely vital that only the proper fluid be used, which is ATF+4.