I have a 89 F350 4X4. I replaced the VSS on the transfer case and the TPS (set to correct voltage). My speedometer quit working, although I installed a new cable.

When my speedo started acting up I noticed my transmission shifting poorly. Now it seems like the tranny is slipping. Normally when going between 15 and 35 mph or up hills. It will rev really high then slam into gear then rev again. I could only make it back home by putting it in second for the last 3 miles. The OD light is blinking but will only blink for a few seconds so its not long enough for me to get a code.

Any ideas on how to fix it? I need my truck or the horses aint gonna to be fed.


I also drained my transmission fluid along with filter change.

I have the E4OD tranny


Thank you in advance