2009 Duramax 4wd noisy

[Stg2Suby]

I bought a 2009 Duramax last Feb with 28k on it, seemed to be well taken care of don't think it was chipped or abused but it did tow a 5th wheel or gooseneck so may have seen heavy towing.

Right away I noticed it was a bit noisy in 4wd, kind of a howl/whine seemed to be coming from Tcase. I didnt' worry too much about it last spring and didn't use 4wd all summer until last week.

Anyways a couple days ago (40k on truck now) at -30c the 4wd howl is worse to the point I think something is wrong. Howls at all speeds but really noticeable on deceleration in lower gears.

Any thoughts what this might be? Any known issues (besides pump rub) with this t-case or front diff? I'm assuming it's not front driveshaft balance issue although this would be nice as relatively easy to fix/upgrade with a CV shaft.

I deleted DPF and programmed it with EFI live so assume any warranty is voided, otherwise I would just have dealer fix it. I may still have to take it in and have them diagnose it but I won't be paying them out of pocket, if it needs work I'll take it somewhere else.

edit: how does the 4wd work by the way, is there a vacuum or electric de-couple sleeve built into front diff? Or is the frontend always turning the driveshaft back to the t-case?

 

[Summitric]

You should have warranty on it, no problem........... If you have troubles with dealers, contact slomo on this site, as he is the head tech at one of the gm dealers in edmonton, and i bet he can get you fixed up]

 

[TRAV]

There is an electric actuator in the front diff that locks it in (moves shift sleeve over gear). The front driveshaft shouldn't be turning unless it is a model with auto trac, then the clutch pack in the transfercase keeps the front driveshaft turning. Wouldn't hurt to check the oil in the transfercase and see if there is much for metal in it. Possibly a bad bearing or something

 

[Stg2Suby]

It's going in to the local dealer next Wed fingers crossed... I explained the situation told them it was deleted and programmed and they didn't indicate the warranty was automatically voided.

 

[SLEDJED]

warranty will only be an issue on things effected by the programmer. If your door handle breaks, its still warranty. If your drive line has issues, its still warranty (with some exceptions ie. transmission) If you loss an injector, you may have to pay. Just because you have mods on your truck doesnt mean your entire warranty is gone, just possibly on the things the mods directly effect. Really it comes to the dealership. My experience is find a mod friendly dealer, thier the ones who sell and install this stuff, their easy to find, they usually have a brand new diesel with a lift kit sitting right in the front row