Flange Wear from CV Joint Options

[frank_c]

Today I started the process of dropping the engine & transmission so that I can send the transmission off to Dr. Evil and take care of some misc engine work (rear main seal, oil return tubes, etc. ). As part of this work I was also hunting for a clunking noise I hear from the back when the car is stopped and as I let the clutch out and the car just starts rolling forward. I already checked and/or replaced all suspension and engine mounts, as well as the outer CV joint bolts (inners are safety wired) and found nothing loose. So next on my list was either the CV joints themselves, or possibly loose flywheel bolts.

When I removed the inner CV joints from the transaxle flanges, I was surprised to see some pretty deep gouges in the flanges from the CV joint inner race/star (see photos below). This seems like a good candidate for the noise I am hearing.

I have never seen this type of wear before with any of the other cars I've worked on - what would cause this? I noticed that there is not much grease in the joints, which I suppose is one possibility. Was the inner race put on backwards? Wrong parts? I did confirm that the axle shaft does move in and out freely at the outer CV joint.

Thanks for any insight.

Left flange:


Right flange:


Circled area shows where inner race is cutting into the flange.

[Jack Standz]

"I have never seen this type of wear before with any of the other cars I've worked on - what would cause this"

Typical wear from 50+ years. Replace (CVs, axles, etc.) worn parts. Lately, we've been replacing with PMS flange adapters and Carrera axles (930 CVs) due to the fact that original style 914/4 CVs aren't available.

OK, I want to revise my wording a little. As mentioned, I've seen this type of wear/damage to transmission flanges before (although, after looking at the photos again this is the worst case I've seen). I've also seen 50+ year-old CVs with deep pockets worn in the groves where the ball bearings move back and forth. Seen broken cages, etc.

So let's say it's not "typical" and definitely not normal. Let's call it "odd". Particularly if these CVs have been maintained or replaced fairly recently. That's different. That indicates improper procedures were performed or improper parts installed. Maybe that's the case here. Additional information would help. Maybe these aren't 50 year old CVs.

Still looking forward to finding out the cause. My money is on hyperextended CVs like @Superhawk996 said. But, why? Could the CVs wear so much that they can hyperextend? Could these CVs not have enough travel to articulate sufficiently for this 914's needs?