I have a '65 w/ an automatic transmission. I have no idea what kind. The car used to be a 6er but now has a 302 and I bought it that way. I have no idea if the transmission was swapped as well. Anyway, when I go from park to reverse, or reverse to drive, or park to drive, I get this very loud and forcefull clunk. I am told by a friend that this is the u-joints, which makes sense because the person I bought it from said the u-joints need to be replaced....I guess this is why he said that. Is this a correct diagnosis? I got under there tonight and tried turning the drive shaft back and forth so I could see if there was any play in the u-joints. I noticed the play was coming from the yoke going into the transmission. Could this be the problem? If so, what is the fix for it? Is there something else I should look for before I can determine what the problem is?

 

I think I have read somewhere in this forum that C-4s have a tendency to "clunk" a Little when changing directions and gears. But if it is as extreme as you say, you might want to invest in u-joints anyway.

It is often very difficult to tell the condition of a u-jointby doing a static visual inspection. Even when trying to physically check for slack, actualmovement is hard (or often impossible)to generate by hand.

 

hate to rain on your parade, but its more likely to be a worn diff.

 

I read that could be the case. Any way to check for that without taking the driveshaft off, or rear end apart?

 

U-joints are cheap, and don't take much time to replace. I'd say replace them and see how that helps/hinders your problem.

 

Is the joint in the yoke moving, or is the yoke itself wobbling around inside the trans output housing?

 

Yep, crawl under and give the drive shaft a twist both ways and look for movement between the yoke and the drive shaft. Do this at each end . Note that there are different sized u-joint caps for your year car so take the old ones with you to the parts store if the old ones need replaced.

 

not the joint in the yoke, it actually seemed pretty stable. I did see it rotate inside the trans. housing. I don't know how good of an indication that is since my shifter sometimes pops out of park or won't go in park (fixing that problem soon with the sifter bushings).

Good idea on taking the old ones to get new ones. I was actually worried about trying to figure out what kind I had. I wonder if a trans. shop could check my u-joints and let me know if that is the problem or not.