My dad just bought a 2001 6 speed 3500 QC with 123,000 miles, that has probably spent most of its life pulling a trailer. The truck has a Van Aaken Smartbox, and some bigger injectors that make a huge difference in power. When idiling along at low rpm in a gear, the trans. makes sort of a growling noise similar to what a Ford ZF 6 speed does when new. Is this bearing noise, and which one it? Also we replaced a driveshaft center carrier bearing that was quite worn, and that helped the noise a little, but it is still there. What is the problem likely to be? Thanks in advance.

 

I have heard the center support bearing is pretty common to go out in those 6speeds.Thats what a local transmission shop told me they replace the most. Especially if pulling alot or high horsepower. Because a friend of mine had a 02 with 700+ horse and thats with the nitrous he went through 4 of them.

 

My truck has the same noise. I bought it in Dec. with 18K mi. and now has 35K. Made that noise when I bought it and makes the same noise now. I have changes Trans fluid and checked everything in the driveline. Can't find anything wrong and have just decided that it is a noisy trans. What the heck, the whole truck is noisy. Sure runs good though.

 

So does mine. The lower the RPM at idle (like with a load or going through soft gravel) it gets louder and worse. To me its just normal.

 

Sorry couldn't resist
Why the bottle...it's a diesel?

 

The question is why not? More power is more power in my book

 

you got that right "Tim Allen".

 

Mine is still stock and has made the low RPM Growl every since it was new. Its especially noticable when pulling away in 2nd gear at Idle speed. Has 145k on it now. Third gear is more of a problem than the growl for me.

Dave