Chrysler Repair: 91 Fifth Ave. Clunk in drivetrain

Question
QUESTION: Hello Roland, and thanks for your assistance in advance.  I have a 91 fifth ave 3.3l.  All of a sudden I have a clunk in the drivetrain that feels like I have a massive rock in my tire when driving.  So every half turn of the tire, coming from the transmission through the drive axle, there is this clunk and the whole engine/trans jumps.  I can reproduce the problem by just spinning the wheel.  The transmission only has 20k miles since being rebuilt.  Do you think this is something simple or will the transmission have to be removed from the car to fix?

ANSWER: Hi Chris,
About the only other possibility is that one of the cv joints on one side is broken. Can you make the noise by turning either front tire (with the other side on the ground)? If so then I would agree that it is coming from inside the transmission. Since it is every half turn that suggests that it is do to either a cv joint or something in the output drive gearing of the trans. I don't recall there being a repair of the output gear that is suggested can be done without removing the transmission if it is internal but I will check the manual and see if that is possible and let you know later today.
Roland

---------- FOLLOW-UP ----------

QUESTION: Hello Roland, and thanks again for your quick response.  That was a great question - "Can you make the noise by turning either front tire (with the other side on the ground)?" - I just tried it, and it only happens on the drivers side.  When turning the passenger side tire with the other on the ground, there is no clunk.  As for the drivers side, I don't see anything wrong with the CV joint.  The boots are in contact and no holes in the boot.  Any other diagnosis suggestions?

Thanks,
chris

Answer
Try rotating the noisy side by using your hand to rotate the output shaft placed on the flange at the transmission (rather that via the tire). That will remove the cvs' involvement in the effort to a great extent, and notice if the sound is the same or gone.
If the sound is still there then that would seem to indicate a problem with the differential part of the A-604 transmission. From what I read in the manual I don't believe it is likely that a repair can be done without removing the transmission even though can open it up enough to see what is wrong because if parts need replacement there are several critical measurement that need to be done that aren't likely to be able to do while the trans is still in the vehicle, though I could be wrong depending upon what needs to be replaced. I would consider the alternative of finding a well-working A-604 from a wreck, but that may be a challenge without knowing the history of the donor vehicle or its owner.
Roland