I have repaired several creaks and pops in the floor of our Pinnacle. I found that the major reason for the noise is vertical movement between the plywood floor and the steel support stringers. The floor is screwed to the stringers from above using self-threading machine screws, and with humidity changes, a small amount of clearance will result in noise.
There are two ways to fix this. It is a two-person job. You will need someone to be inside the rig, making the noise, while you're undrneath with a flashlight. One way is to insert a wooden wedge shim between the floor and the stringer, from underneath. The best way, if you can get access, is to drill a hole from underneath through the steel stringer flange and use a 1/4 inch lag screw and washer. You may have to cut an access opening in the coroplast underbelly covering, or if you're lucky, you can get to the creak through the slide mechanism access hatches by removing the screws.
Our most-annoying creak was in the kitchen, and this one was caused by a joint in the longitudinal 2x3 joist, which Jayco spliced with a flimsy galvanized metal joining piece. Any relative movement here resulted in a very annoying creak. I fixed this one by glueing and screwing two 1x3x12 inch long pine pieces to each side of the 2x3 joist.
Our floor is now quiet. Even though it took a few hours of poking around underneath, it was worth it. I'm not sure that most dealers would have the patience to track down these creaks, or even that Jayco would approve a warranty claim, because it is so time-consuming.
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David and Denise, fulltiming since 2011.
Pinnacle 36RETS, Samsung RF197 refer, 17.5 wheels/H-rated tires, Mor-Ryde pinbox, wet bolts and X-Factor, Monroe shocks, TireMinder TPMS.
2013 GMC 3500HD DRW 2wd, AirLift rear airbags, Curt Q20, 46 gal ATI transfer tank, Yamaha 3000iS in pickup bed