Howling and not at the moon!

[GCrowell]

I have a recent new 'noise' coming from my 48RE. I have noticed it only since it turned cold here; been in the 20's last few days. During normal launch, I hear a whine or like a light howl from the transmission in first and second gear. I cannot hear it in 3rd because of normal sound levels so don't know if it is there or not. It is loud enough inside the closed cab to sound like our local volunteer fire department siren. It is definitely related to speed whether accelerating or coasting. Sounds a little like a gear noise an old mid '40s truck with standard transmission would make taking off under load. I haven't driven it enough to know if it will go away when everything gets hot. It still shifts 'normal' and there is no hesitation or slipping that I can notice. I have about 18k on the clock with about half that towing 12k.



Anyone heard of this or have any suggestings before I take it to the dealer?



BTW I believe my dealer is honest but may not have as much experience as some others so I would like to go in armed with some knowledge from this vast experience base called TDR



George

 

[lschultz]

You sure its not your turbo making a little howling. This is the first morning I noticed it on mine as I turned into the plant and its my turbo. It was between 26 to 29 this morning. I think its been talked about on here before about the turbo making a little more noise/howl/growl or whatever you want to call it when its really cold.

 

[GCrowell]

Larry,

I don't think it is the turbo because it is independent of the engine speed or load. That is, it will howl when I just let it roll down hill from a stop without any throttle change. The frequency of the sound changes directly with speed of the transmission it seems. That is, it winds up while in first, then when the transmission shifts, the frequency abruptly reduces and begins to wind up again as the vehicle speed increases. It is loudest in first gear, not as loud in second and by third, I cannot hear it well at all.

I have never heard my turbo make any noise other than the light whine one would expect and that is very quiet.



Thanks for the thoughts.

George

 

[Hawkeye 04]

It's probably your rear diff. Mine does it on cold mornings until it gets to the warm operating temperature. After that it quiets right down. It's annoying, but it's done that since it's been new. Some people have reported that they solved the problem by changing diff fluids. Other reported no diffrence. I need to change mine and see what happens. I personally think it's due to the stiff oil on cold morings... .