vibration problem

[bbrroowwnn]

To the OP , If the vibration only happens in acceleration and deceleration it is usually the pinion angle not being correct...... Also, I see a lot of guys are having vibration trouble and there is a lot of good info in here to check but I want to throw something else out there that no one has mentioned yet.... My transmission guy who has been rebuilding transmissions his entire life and has done 1000's of mopar 727's mentioned to me when I was putting mine back together after he rebuilt it for me.....He said if you have a EXTERNALLY balanced motor and are using the stock flex plate as I pictured below , which would then require the weighted torque converter...When you put the 4 bolts into the lugs on the converter make sure the small hole that I circled in red is across (opposite) the weights on the torque converter.....He said if not you will get a vibration for sure.... Just throwing it out there....may help somebody out

 

[trudysduster]

vibration problem corrected. I have finally fixed the problem. I believe it was a combination of problems. I replaced the tailshaft bushing. It was chewed up a little from the driveshaft being 3" too short which by the way has been corrected. I changed the u-joints just because I had the driveshaft out. I checked the tire balance which they told me was perfect. I think the big problem was the pinion angle. I cut the perches off and replaced them. without welding them on first, I set the housing in the perches and set the angle where I thought they should be and tightened down the u bolts and without the tires on I ran the car in drive adjusting the angle till the vibration was gone. I would up with the pinion angle at 8-9 degrees. The specs was 7-10. The local spring shop told me to look for 3-5 degrees. So, I guess the answer is to do the trial and error as each situation is different. I also changed the gears and went from the 4:10 back to the 3:23 I had in there in the first place. Made a world of difference. Now if I could get the carb loading up fixed next I will be a happy camper. Thanks to all of those who responded to this thread.

 

[HMBCUDA]

Unfortunately I've joined this club now too...This good "old" post gives me an idea of possible areas. i was thinking u-joints...I hope not trans. shaft bearing...let the chase begin!...