When driving the truck I notice the shifts are hard and at around 2500-3000 rpms. If I let off the gas around 2500 the truck will shift and it bangs hard into next gear. The other way is wot and the trans ****fs better and not as hard. The down shifts seem to take a little to be noticed unless i go wot. At this point its like it goes to neutral for a split sec then down****fs. Any thoughts? trans need rebuilt? TPS is bad and needs replaced?

 

Have the codes read for the transmission
That is not easy on a 1991 without a Ford NGS scan tool
You might come back saying there are no codes, possibly, when there are in fact codes stored
That said, it might not be a code issue at all
If your filter falls out it will do the same thing as it starves for trans fluid to shift
If you google hard shifts on a Ford E4OD, you will be reading about filters out of position IIRR
So, the fluid level and the filter being installed correctly with a good seal needs to be checked
Most trans shops are going to want to service the transmission to check those two things
TP and the VSS are the important inputs for the E4OD to shift correctly
With the NGS you can check both of those easily,
You will need to backprobe the connector with a DVOM most likely
For instance, back in the day, people would disconnect their speed sensors and make the speedo not rack up miles
That prolonged their warranty period
That also made them shift hard as a rock
Good luck

 

Thanks for the info, I now the speedometer does not work so maybe that's a good thing to check and do a service on it.