Vibrations while driving and while car is parked.

[Gilad Avital]

Hello all,
On my 1975 Valiant slant six automatic transmission there are strong vibrations.
My mechanic installed new motor mounts and new transmission mount,still strong vibrations.
Engine is tuned good and not shaking while ideling.
Can it be faulty harmonic balancer?
Thank for your help.

 

[Demonracer]

It could be that the outer ring has slipped on the balancer. Another thought is to take the driveshaft loose at the rear axle and spin it 180*.

 

[Oldmanmopar]

If you did not change anything on the reciprocating parts on the engine or trans Then it would have to be something that failed. here are some things to check

1. slipped outer damper ring . Can be checked by putting the number one piston at the top and look to see if the timing marks are aligned

2. Cracked flexplate .

3. loose or missing flex plate bolts

4. Failing torque converter.

 

[Gilad Avital]

Thank you guys,Ill have my mechanic check all of this things.

 

[67Dart273]

It could be WAY simpler. Did he change mount BECAUSE of vibration, or did the vibrations start AFTER the mounts were changed?

Because you could have some part of the engine/ transmission hitting "metal to metal" on the body / frame, and conducting/ transmitting what you are hearing/ feeling

 

[Gilad Avital]

It could be WAY simpler. Did he change mount BECAUSE of vibration, or did the vibrations start AFTER the mounts were changed?

Because you could have some part of the engine/ transmission hitting "metal to metal" on the body / frame, and conducting/ transmitting what you are hearing

Hi.
The mechanic changed the mounts because of the vibrations.

 

[RogerRamRod]

Did you piss somebody off that might have dented your driveshaft with a hammer? Or run over something that dented driveshaft?

 

[Gilad Avital]

Did you piss somebody off that might have dented your driveshaft with a hammer? Or run over something that dented driveshaft?

Hi Roger,
Didn't piss anybody...
When the car is in parking and I press the throttle pedal to give it some higher RPM I also fill the vibrations...
But we will check also the driveshaft condition.
Thanks!

 

[Gilad Avital]

About the transmission mount:
Where there mounts with some kind of special weights attached to them?
On my original mount there is a peace of metal with two nuts welded to it....