Replaced my ujoints a few months ago.. i heated the plastic out of the old ujoints and put the new ujoints on and w/e everything was done correctly, but i get an insane vibration at 65+.. ive had the driveshaft balanced twice by a top end company, and theyve pulled it apart and w/e and done checks they said everything checks out.. but i just dont understand why the vibe would start right after i put in the ujoints.. i mean it was the first road i got on it did this so it has to be something on the driveshaft. i read an old thread about the same things on other peples cars. what should i do to fix this im totally stumped :/ thanks if you can help at all

 

ttt anyone have any ideas?

 

Mine was doing the same thing when I had my 700r4 at like 3200 rpm. Then I switched over to a 5 speed and it stopped. lol Very random but every third gen I have been in does it at a different rpm it seems. R your engine mounts good and is your flywheel still tight to the crank. When I had my auto I had four flex plate bolts come out before. All manuals move a little, but shouldnt move excesively.