I have had a vibration @2K rpm since I've owned my truck (all gears, all speeds). There is a TSB to fix this problem in the 03s by putting a weight on the hydro boost line. Nobody will do the TSB to my truck because it is an 04 and supposedly not applicable. Anyway, I built my own weight and got rid of 80% of the vibration. I just installed the MBRP 4" exhaust and the rest of the vibration disappeared. I am also surprised how quiet the truck with the MBRP system. I’ll see how it works pulling the 5er this weekend. I can hold each gear longer now without the urge to shift because that **** vibration if finally gone.

 

After 8 hours of towing the 5er this weekend, what a difference. I have a post turbo pyro that used to reach 900 degrees pulling small hills in 6th causing a downshift. With the new exhaust the EGT never went over 800 degrees. The only time the exhaust got loud was when I accelerated up a steep hill in 5th gear with my foot in the floor (passing people just because I could). Compared to last summers tows my MPG is up almost 2, from 9-10 last year to 11-12 this trip. It was 101 degrees outside on the way home according to my overhead. I filled up before the trip home the overhead matched the hand calculations at 11.8 (trip out). I haven't filled up since getting home last night but the overhead tells me I got 11.0 on the trip home.

 

How heavy is the 5th wheel?

 

10,000# area and it is nearly 13' tall so wind resistance has huge effect.

 

Did you do turbo back or cat back?

 

I have to agree with the MPG increase with the MBRP... No body seems to believe when people say they get a good 2-3 mpg increase... well my truck seems like it did with every fill up since it's been installed. been 4 months now...

 

I don't like cats so I bought my truck before they were installing them. New exhaust if from the exhaust brake elbow back. Cats weren't put on till 04.5 and mine is an 04 triple nickel (555)