Driveline Harmonic??

[TLH101]

'63 Dodge 330 wagon with 727 and trunnion style driveshaft. I have (for lack of a better description) what feels like a harmonic vibration around 68-72 mph. Happens at 34-36 mph as well. Trunnion has been rebuilt and rear u-joint is in good shape. Car has done this since I have owned it.
Could this be a drive shaft out of phase? I always mark it and put back where it was but maybe has been done differently over the years.
Any chance rotating the u-joint 180 deg. in the yoke will help?
Or should I look elsewhere?

 

[69 Sleeper Bee]

Couldn’t hurt to try if you know the trunnion joint and u-joint are good.
Did you check tranny mount or pinion angle to see if they are good ?

 

[493 Mike]

Couldn’t hurt to try if you know the trunnion joint and u-joint are good.
Did you check tranny mount or pinion angle to see if they are good ?

I agree. Check the drive line angles. I had a similar problem back in the early 70s with a B body at work. I had to shim the trans mount to correct it if I recall correctly.
Mike

 

[HEMI-ITIS]

Check the tires for balance , bent or out of round tire.Then as said check the driveline joints,

 

[Dave6T4]

If it related to engine speed, it could be a bad water pump. It happened to me. Grab the fan blade and see if it wiggles side to side. I first felt the vibration in Drive, but could replicate it in First and Second as well by selecting the gear manually.

 

[Lefty71]

My `64 was doing that.... had me all worried then it went away. I`m pretty sure it was because the front portion had an overabundance of grease trying to protect that trunion joint. The goop spun out on the floorboard and the road, and the thing smoothed out like it was '64 all over again lol.

 

[Geoff 2]

I would check the trunnion joint to make sure that didn't forget an endcap on the T piece.

 

[1STMP]

You might want to check flex plate for loose
or cracked bolt mounting locations. If it were
a driveline angel problem, it would be constant
and not at various speeds. Does the same
problem persist under load or coast
conditions, or flat vs crowned road conditions?
Wheel/tire runout, bearings, harmonic
ballancer.
Run it thru the mill to narrow the problem down. Take notes. Tracking this down will
be a lengthy process of elimination.

 

[493 Mike]

You might want to check flex plate for loose
or cracked bolt mounting locations. If it were
a driveline angel problem, it would be constant
and not at various speeds. Does the same
problem persist under load or coast
conditions, or flat vs crowned road conditions?
Wheel/tire runout, bearings, harmonic
ballancer.
Run it thru the mill to narrow the problem down. Take notes. Tracking this down will
be a lengthy process of elimination.

The issue I detailed earlier in the thread was improper angle at the transmission and it only occurred in a single speed range. My experience.
Mike

 

[1STMP]

My apologies, Mike.
Was offering advice after having similar
driveline problems on lifted Jeeps. Just
trying to be helpful.

 

[493 Mike]

My apologies, Mike.
Was offering advice after having similar
driveline problems on lifted Jeeps. Just
trying to be helpful.

No need for an apology! Just stating my experience on a warrantee issue on a new Dodge B body back in 1970 at the dealership I worked at.
Mike