TR2/3/3A Slight clunk in the rear assembly somewhere.

Slight clunk in the rear assembly somewhere. I thought this clunk might be a U joint or a bad spline on one of the wirer wheels, but after I started looking around under the car I think it might be too much play in the rear flange at the U joint. The U joint seems fine and might have 7K on it. So, How much play/slop should there be before the drive line goes into motion. There seems to about ¼ to 3/8 of an inch before the drive line is firmly engaged plus that could be the clunk.

Steve...you're back! I thought the Chinese might keep you to extract Triumph secrets!

1/4 to 3/8 sounds pretty typical for the pinion gear play. The real key for a differential is if it makes noise, especially passing 30mph, 60, 90, and 120mph's. If that flange were loose it would make a lot of racket. U-joints will give you a high frequency vibration when they go out... and they are normally noticeable when you grab hold of the drive shaft (car in neutral) and rock it back and forth.

Hopefully it's just something simple, like the brake assemblies dragging slightly and rocking back and forth with the drum motion.

I'm confused; are you saying the flange moves relative to the driveshaft? That's a serious problem.

But if it's just backlash inside the differential (pinion turns but wheels don't move), that's no big deal at all. I'd say 1/4" is about normal, but my last TR3A was worn until it was more like 1/2 turn! Most likely wear in the brass thrust washers (the "yellow metal" bits), possibly caused by using the 'wrong' oil (before I got the car).

If I grab the drive line and twist, there is about 3/8 or so play before anything happens. I can rock it back and forth or in this case side to side; it does not go in and out. So I guess that is what John is saying—the ring and the pinion have movement.

I have rebuilt everything I can think of except the differential. Over the years, I would just find a used one and replace the unit. An old buddy of mine would saw that, do not bother trying to fix one of those because they are never the same and difficult to get correct, but that was many years ago.

Yes I am back from South East Asia. I made friends with some Cambodian people when they left after the Kamer Rouge or Chinses Communist genocide back in 1977, and have been there many times since. I am here to say the Chinses are back in large numbers and have actual purchase one whole beach town and discourage English spoken there. The Chinese are taking over Cambodia and Vietnam by legal means with the money we give them. Heck look around everything is made in China. The Chinese that relocate there can have more than one child plus I heard they cannot go back to China. I could go on all day about this—it might get ugly over there again.
steve