The MLPS in my '92 F150 has been replaced twice in 23 years. A couple of weeks ago the transmission started up with the harsh shifting routine. Classic symptoms of another bad MLPS. So before installing another new one, I decide to do a search on this forum. One of the first search results showed a post from someone who said his truck had the harsh shifting when it was wet or raining. He fixed it by just cleaning the MLPS connector and pins. It just so happened to be raining the day my symptoms started! The connector is located in a rather vulnerable position; lousy design. I can totally see how water could get in there to cause problems. Upon disconnecting it, there was some black crud built up. The last MLPS has only been in there a couple of years. So I cleaned it out good and sprayed some contact cleaner in there, let it dry and reconnected. I wrapped the top with electrical tape (where the wires go into the connector) and the connecting components too. It works great! I tried several times without luck to find that original thread to thank whoever it was who suggested this fix. So thank you, whoever you are.

 

Before it cruds up again from water, put some dielectric grease in there to keep the water out..