I did quite a lot of research on the factory harmonic balancer cummins uses and all the posts on our forum, and you guys are worth your beans, never seen a bad suggestion or product eval. so I bought one from one of TDR's advertisers,XDP (XDP Truck & Jeep Power) got a "special"price, plus a TDR discount 367. 62 free shipping that was it!! everyone else's price was $470. 00 plus shipping,took 20 min to install, and no $###, feels like a different truck! vibrations I didn't even know I had, are gone. shifts easier,idles MUCH smoother, goes thru gears smoother, cruising speed (75) feels like my wife's subaru ltd outback (they are one of the most vibration free vehicles built because of the boxer style motor) but mine has about 300 more hp. LOVE this damper. thanks guys, money well spent thanks to your posts.