So, I haven't been on this forum in a few years but I'm glad to be back. I have a 72 240 with a 2.8 and a 5 speed. My diff is the stock 240 ( I believe its a 2.70) so my drive train is a bit of a "hybrid". On to the problem...

When I accelerate, or down shift, basically whenever there is torque on the drive train i hear a sharp "crack" and then some "scratch, scratch, scratch". coming from the rear passenger side

When I look under the car I don't see anything "odd" no metal wear. I'm wondering if its the needle bearings in the half shafts. But what is the "Crack" sound? I replaced the differential mount about 7 years ago so I don't think that's the problem.

I'm thinking about pulling everything from the drive shaft back and replacing it... big job... lots of time... grrrrrrr.

Any suggestions would be great!

Thanks, Matt-

Take a look at your U-Joints, starting with the passenger side and on from there. jlp

Yea sounds like a U-Joint is failing. Give em a wiggle.