i have a 1988 f150 5.8L manual trans 4 speed. i was driving home and started to get massive vibrtion and could not go over 40mph. the shifter was shaking like a martini. i changed the engine and trans mounts. and it is still happening.

Yes the trans mount had tares in the rubber and also both of the engine mouts had tares all the way around.

I am thinking along with the mounts a ujoint want out. or tale shaft baring on the trans?

any though would be great.
thanks!

 

My guess would be a bad U joint. Not hard to inspect. Park the truck where it can't roll and away from traffic and put the transmission in neutral so the driveshaft is not holding the vehicle from rolling. Crawl under the truck and vigorously twist and push up and down on each U joint while you watch and feel for looseness.