Vibration??

[Three-nuts]

Well, replaced the motor over the course of the past week. Motor runs great; very smooth.

I still however have:

-- vibration at idle (even after setting the timing and the RPMs to spec.) once dropped into any gear.

-- hard shudder on hard acceleration, and very hard shifts. During the motor changeout I found the kickdown rod was disconnected; once reconnected, the trans will shift from 3 back into 2 at the slightest touch of the throttle at any speed under about 60 (hard to say exactly when, as the speedo has quit working...)

At high speeds, everything's fine...no vibration or shudder.

Also: there is no noise.

The replacement motor came with a trans, both described as having 44K on them. I'm thinking of first swapping out the driveshaft, then the transmission if that changes nothing.

Appreciate any input, and particularly about the torque converter.

 

[kielbasavw]

I have similar problem. I posted on transmission forum and they said it's nothing with the trans failing.I think its an intake leak. I looked high and low for one and finally found out it's from a very sloppy throttle shaft. Spray some carb spray in the shaft. If it rises or kills idle. There you go. I'm in the process of trying to find another carb with a good shaft.

 

[Three-nuts]

It's not a vacuum leak, I checked for those after installing the manifold. The motor has a dead-smooth idle at 750RPM, the rest of the car vibrates as though the motor was welded to the frame (it has new motor & trans mounts). The real fun starts on hard acceleration.

It appears that the 904 in the car has a lockup torque converter, which means it's a post-1978 unit. Lockups had this hollow spline shaft with a smooth shaft sticking out the middle:

versus the non-lockups, which have a solid spline all the way to the end.