I have a problem that I can not figure out. The car develops a knock/clank sound in the mid-rear of the car at 55mph in OD in the 1500-2200 rpm range. I have also experienced this in 3rd as well in the same rpm range, but it is not as easy to hear or feel. I checked the mounts under the car and everything looks solid and seems tight. I ran the car up on stands to have the wheels spin and searched for the noise, seems to be in the rear end but it is very hard to tell. We applied the the E-brake and ran it in the same range (55mph, 1500-2200) and the sound was not there.

We then turned the car off, put it in neutral and rocked a wheel back and forth. This generated the same sound and the wheel felt like it had a lot of play before it actually turned the driveshaft and such.

Any advice would be great, I have done some searches but have not come up with much. I will try to get a sound clip if I can.

 

u-joint. check the fluid level in the rearend

 

Just put new fluid in the rear and changed both u-joints. But the battery died, I'll know if it fixed it in a few hours after it gets charged up. Hopefully it does, the car needs to make it from CT to VA next week so I don't have much time.