Hi, I am trying to figure out why my transmission is losing both forward and reverse gears. When this occurs it feels more like a rough idle or some kind of ignition issue and then there is little power, then the transmission just slips and there is no forward motion (no reverse either). If the van sits for ten minutes or so it will drive again, but not very far before it will happen again.

This happened for the first time yesterday and the fluid was showing the level was too high. We thought that the problem was the filter was clogged preventing the fluid from reentering the transmissions and pooling in the pan. After having the van towed home I was able to drive it onto the driveway with no noticeable problems. We replaced the filter and added 5 qts of new fluid. (car place said it should take 5-7 qts.) It was showing high on the dip stick, maybe an inch and a half to two inches above the hot range. (I am checking with engine warm after going through all the gears a couple of times and with the engine running in park.)

After replacing the filter I test drove the van for a couple of miles and it worked fine. We drove about 20 miles throughout the day going from job to job and driving about 30 minutes at a time. It worked fine all day. On the way home I started getting the running rough feeling and within a mile or so I had no forward. I pulled off the road and also had no reverse. After about 15 minutes of sitting I had both again, but did not trust to drive again.

My brother found where the "VSS" could cause these symptoms. I went and bought a code reader and it says there are no code stored and shows nothing to work with.

Anyone have any advice on what I may be dealing with. Would like to get this fixed with minimal trial and error. This is also our work vehicle and we have jobs tomorrow. Any help would be greatly appreciated!!!

Thanks,
Jeff

Vehicle is a 1997 Chevy Express 1500 with the 5.0 engine