Reply to ""Clunk" after gear change and gas"

U-joints are easy to periodically check. Look down on each u-joint end-cap; is there a shiny circle (also known as the 'ring of death') around the visible edge of a cap? This comes from the cap beginning to rotate in the yoke due to incipient seizure of the tiny needle bearings inside. This is more difficult to see on the outboard u-joints but it can be done with jackstands and a light; outboard joints fail, too.

Got pretty logo-covers glued over the u-joint yokes so you can't see the cap-ends? Another way to check is to reach in with a finger, and run it around the inner part of the u-joint cross where it touches the yoke. If your finger comes out red mixed with grease, that's rust from rapidly rusting high carbon steel from failed needle bearings. Check ALL 4 legs of ALL 4 u-joints.

Rotating caps will thrash out the required press fit in the yokes, trashing the entire halfshaft in a short time. There are no replacement halfshaft parts and cannibalization does not often work. If ignored, a failing u-joint will eventually break, freeing one end of the halfshaft to flail around like a 10-lb war-club and smash things- like your ZF cases. Fixing this takes removal from the car followed by complete tear-down followed by TIG-welding and remachining. I've redone several such ZF cases. New u-joints are 50X cheaper.

Another thing that makes noise a sensitive driver might notice: the lower a-arm studs run in bronze bushings (2 in each upright) that may not have been greased since DeTomaso assembled your car. They wear egg-shaped and engaging the clutch makes the end(s) of the stud(s) visibly move and make a little noise. The motion or sound is not much but as I said, some drivers are VERY attuned to changes in their machine (which is good!)

Finally, ring and pinion differential gears, and transmission gears do wear out after many miles of hard use.... One easy driving So-Cal owner I know has WORN OUT two ZFs (but then, he has over 250,000 miles on his beloved Pantera.)