Driveline Clunk

Having suffered with the clunk for some time on my '99 2wd Tahoe I finally took it to the dealer. With some reluctance the dealer agreed to put some grease on the splines. Problem solved - for now. I have been reading this thread for some time and it seems that the problem will reappear in a few weeks. Someone had posted a note that they added some coil springs from JC Whitney to the rear end and this solved their problem. Could that person let us know if that fixed their problem permanetly? If it did, would they shared some numbers, costs, how-to's, etc. Thanks in advance.

Does anyone else know of a semi/permanent fix...??? I would not mind relubing every 6 months if a good lube is found that will last that long. This problem is starting to make me look at Fords and Dodges and (heaven forbid) Toyota's.