Intermittent noise when accelerating in low gears???

[Diesel Gal]

'04 3/4 ton 6 speed.



I'm noticing an occasional noise when I'm accelerating in the low gears. sounds like a fast RPM type noise, a roar or like the clutch fan. There's no associated power surge, in fact, possibly slightly less power when it happens... . like I'm not getting the acceleration that I would expect. Very sporadic and goes away as I shift upwards. Any clues before I call the shop (which is 1 1/2 hrs away). Only major modifications have been an exhaust brake added on about 6 weeks ago. 4500 miles. no chip.



Thanks!

 

[HOCummins04]

Welcome to the site. Afraid I am not going to be any help. My engine is different, and don't have 200 miles on it yet. No problems with engine so far. Did it happen before EB?

 

[dseabaugh]

I wouldn't worry about it. It is just the sound of the pavement buckling under all that high horsepower and torque!! Oo. Oo. Oo.

 

[boonsur]

It's probably your cooling fan kicking in. The clutch will engage under certain conditions (high temps, AC on, etc. ). Only stays on until 20-25 MPH, or so. Then it drops out, assuming there is enough air flowing over thte radiators without the fan assist. It speeds up & down with your engine RPM's because it's driven of it. I think it sounds sweet - let it roar!

 

[rbattelle]

Couple things to check

It's hard to diagnose this problem from your description. If it sounds like the fan, maybe that's what it is. Or, is there any chance you're lugging the engine? You will notice that when cold it will knock (aka ping) quite a bit sometimes at the lower RPM range.

 

[rbattelle]

Oops... Boonsur beat me to it!