harmonic balancer is on the front of the engine. round chunk of metal that the crank pulley bolts to. if vibration is there rolling in neutral its deff not engine related.
check all the bolts for the transmission mount & crossmember, also look at the rubber part of the trans mount. if its torn that would let the tailshaft of the transmission wobble. that could cause a vibration.
also check to see if the front yoke of the driveshaft is fits tight (no wobbles) on the transmission tailshaft (or inside the trans hole). IF that doesnt fit right or is loose thats your problem.
if that isnt the problem, then all thats left is the rear end. hope you figure it out
Have a vibration issue with my 71 tang. The 40 year old trans mount had collapsed the rubber so that the metal part of the trans mount was resting on the metal cross brace. Every vibration in the drive train went right thru the body and shook the whole car. A new trans mount eliminated most of the vibration. The engine and trans are not supposed to have any metal to metal body contact. The rubber in the engine and trans mount prevent metal to metal contact but eventually wear out. At one point I thought the vibration was the rear third member which I had rebuilt but did not get better. The differential specialist told me differential problems cause noise not vibration. I also had the rear axles spun on a lathe to check for bent axle but that was ok. Also could be the torque converter wihich also has to be balanced. Good luck.
Car is out og winter garage, and I am back at my problem. Last check by guru-mechanic concluded that the vibration is there at idle (at different rpms), and problem started after AOD swap.
He hinted that it could be caused by faulty converter in AOD. Anyone experieced with this?
What flexplate did you use? The swap requires a conversion type flexplate because the 5.0 that the AOD came from and your 289 are not balanced the same. The C4 flexplate won't bolt up to the AOD converter. The AOD flexplate will bolt right up to your 289 crank, BUT will cause vibration due to the balance differnce.
I am also having vibration issues since my AOD swap. Vibration happens at all times, even in park, leading me to believe it is a flex plate mismatch. You mention that the 5.0 flex plate will cause vibration (I have a 289/302), the C4 flex plate won't fit, and the AOD flex plate will fit but will cause vibration. My transmission guy claims there is only one flex plate that will work, and it is an AOD flex plate. What flex plate do I need?