Ok, it took me forever & three days to find out what was causing the bowling ball effect. Last year I greased the rear driveshaft splines and WOOLAH....fixed, no more bowling ball clunking...for all of two months. Every two months SINCE I have to pull the rear shaft and grease the splines. There is still grease (not dryed) in the shaft so why have to grease so often & IS THERE A PERMAMENT SOLUTION???

 

Thats probably not the problem.

 

worn splines???? new grease is helping silence the noise and gets dispersed along the splines as the shaft moves causing the noise to come back over time.

 

Could be worn splines.....but I would think I'd have a vibration if it were....