My 96' E4OD transmission shifts hard sometimes. I have had the transmission rebuilt, replaced VSS, and replaced the TPS. Also, the speedo bounces all over the place while driving. Any Ideas?

Im having it taken to a shop that says it is probably a "speed buffer?" but I can not find anything about a speed buffer on our trucks.

This is getting frustrating and im worried about the hard shifting other stuff up.

Please help.

 

The speedometer bouncing and your shifting is related, check for breaks where your speed sensor wiring meets the frame. There is a TSB about this problem if you can find it, TSB stands for Technical Service Bulletin and is issued where a recall is not required by law.

 

AHA! Took my truck to a shop, they said the VSS sends the info to the instrument cluster in a stream format then the cluster converts the info into a pulse format and sends it to the computer.(or the other way around) They said the cluster was bad and I needed a new one. Got a instrument cluster from a junkyard, threw it in, shifts like new! It solved all those problems. Thanks mitchalvin, you were right.

P.S. - My truck had the cluster with no tach. Got the one with the tach and it works... just plugged right in, same as the old one.