vibrations ugh. what do you guys think?

[calicuda70]

ok guys need some help/advice after replacing the tranny converter getting the drivshaft balancedand u-joints replaced the car still seems to be the same when i go above 50-60+ mph i get a terrible vibe but when i deccel it grinds and clunks weird i know i dont know how to describe it ive checked the pinion angle since i have the summit 1 inch drop spring sitting at 5 degrees down and have checked the rest of the car over so im at a loss almost a reaching out to anyone who can help or give ideas ive read some of the other topics likes this and tried things but no luck what do you guys think and the car is a 70 challenger 360 with 727 with 3:55

james

[MEK-Dangerfield]

It's weird that it only does this on deceleration.  Are you applying the brakes at this point?

[dodj]

Did you replace those parts to eliminate the vibes or did the vibration show up after they were changed? Ill asume you replaced the converter with one for the externally balanced 360?

[calicuda70]

It's weird that it only does this on deceleration.  Are you applying the brakes at this point?

no just letting it coast down.

[calicuda70]

Did you replace those parts to eliminate the vibes or did the vibration show up after they were changed? Ill asume you replaced the converter with one for the externally balanced 360?

i replaced them to hopefully stop the vibration but no luck lol, and yes it the externally balanced converter im also running the b&M half moon flex plate for it.

[brads70]

You said 5 degs on the pinion angle. What angle is the trany motor at? I'm wondering if this is the problem?

[Chryco Psycho]

are the U bolts tight I wounder if the diff is changing angle , are the seat on the axle tubes welded properly . Any problems with the gearset ?

[calicuda70]

You said 5 degs on the pinion angle. What angle is the trany motor at? I'm wondering if this is the problem?

yea 5 down also running poly mount on the motor and trans, what angle should the tranny/motor be sitting at and do i just put the angle finder on the tailshaft?

[calicuda70]

are the U bolts tight I wounder if the diff is changing angle , are the seat on the axle tubes welded properly . Any problems with the gearset ?

u bolts are tight, axle seems to be fine i have another ebody rear end with 4:10 i thought about putting in just to check and see if anything was wrong with my current axle but i cant see anything and the gears were replaced last year and was doing it before i put them in.

[brads70]

yea 5 down also running poly mount on the motor and trans, what angle should the tranny/motor be sitting at and do i just put the angle finder on the tailshaft?

I always thought it was good to shoot for 3 degrees?   More if it's a drag car? Some say 5-7? Do a google search on it , lots of info?
http://www.hotrodhotline.com/md/html/drive_shaft_harmonics.php
http://www.moparts.org/Tech/Archive/axle/8.html

[dodj]

yea 5 down also running poly mount on the motor and trans, what angle should the tranny/motor be sitting at and do i just put the angle finder on the tailshaft?

Yes. I removed the yoke and measured off the face of the tailshaft. I think Sledgehammer recommended that method to me.

[dodj]

Did you check/rebalance the wheels?

[brads70]

Rear axel bearing?

[Chryco Psycho]

BFG tires are never round

[calicuda70]

I always thought it was good to shoot for 3 degrees?   More if it's a drag car? Some say 5-7? Do a google search on it , lots of info?
http://www.hotrodhotline.com/md/html/drive_shaft_harmonics.php
http://www.moparts.org/Tech/Archive/axle/8.html

thanks for the link brad gunna get some wheel ramps and put her up this weekend and check all that stuff.