Engine/Transmission (1998.5 - 2002) Engine Rapping

[Stan]

My truck has the 1998. 5 24 valvue Cummins engine, five speed transmission and standard gears and 106,500 miles on it. It is stocks. I tow a 32 foot fiffth wheel coast to coast twice a year and north to south some. Some 45,000 miles have been towing.



When towing up a good grade with the trailer on(13500 lbs) and in 3rd gear at 2400 rpm about 35 mph I get a heavy rapping sound that starts quick and grows louder. I let off to about 2000 rpm and the noise is gone and it pulls fine.



My mechanic says it would be hard to duplicate and is searching for an answer. Any thoughts about it would be appreaciated.



How come these things happen right after the warrentee runs out?



Stan

 

[Turbo Tim 1]

Knock or Rattle TSB



Try this link, it is about a knock or rattle while towing heavy loads. Print it off and bring it to your mechanic.

 

[Stan]

Turbo Tim 1



You've made me a happy man. I have been thinking injectors, injector timing, pressure, fuel pumps, PCM or something more expensive. A thermostat I can handle. That would be a great fix.



Thanks for the help will keep you posted.

Stan