Rear transmission extension question

[67mopar]

Hi Everyone
My transmission extension where it bolts on to rear crossmember has ony one bolt holding it and it should have 2 i fixed this when i discovered it. My question is could only 1 bolt in cause a vibration around 60 mph?
Thanks

 

[Lefty71]

Possibly, if the mount was allowed to twist or otherwise allow the trans tail to move from its centerline. I have seen them missing a bolt and still sitting in the proper location, no vibration. Maybe not a lot of stress in this area, just a good bit of weight?? Probably a real issue if one of the motor mounts breaks too.

 

[CBODY67]

Check the front u-joint for wear and the driveshaft yoke for wear in the tailshaft bushing it wears against (behind the tailshaft seal).

 

[MONC440]

It could if one bolt was missing and the other was loose. Is the vibration still there after installing the other bolt? If so I would guess the vibration caused the bolt to come loose and fall out. Like was already stated, check your u-joints.