As the ad says, Just do it. I did it on my 94 850 and now it runs like it did new. I had the dealer do the previous ones since it was still under the extended warantee, and now i am questioning if they ever really did replace the whole thing with new fluid. Bay 13 has fantastic instructions and it truely is one of the easiest maintenance items to do. its easier than a oil change which if you have done one is already pretty easy. I purchased new o-rings and clamp, its not necessary but for $4 why not. I will do it again in 15 -20K miles depending on the looks of it. Ken