2015 6.0 Drivetrain Clunking?

[WiscoZ71]

Hey guys. 2015 4x4 6.0 with about 29k miles. I've noticed that when I take my foot off the accelerator there is a slight clunk coming from what sounds like the transmission. Usually happens about 40 mph and under. I've gone to the dealer I bought the truck from, and they've basically washed their hands of it. I took a tech along for a ride, as well as a service advisor and both heard the noise, and have told me "they wouldn't know where to start with diagnosis". 

 

On an sort of unrelated note... when do factory warranties begin? I was under the impression that they begin on the date of purchase. This service advisor tried telling me that my factory warranty was expired. I bought the truck in September of 2016. 

 

Any input from you guys would be appreciated, I feel like I'm wasting my time at this point trying to chase it down.

[sillywillie07]

Your warranty starts the day its put on the road.  In service date.  So that means when you bought it.   

[GTBensley]

Unless you bought it used, then it would be whenever the first buyer purchased it.

 

Mine also has a slight clunk when I lift if driving gently. Never been worried about it and consider it normal. I have a 2016 with 20k on it. 

 

Find a different dealer.....Doesnt sound like you want them working on your truck. 

[ewbldavis]

Mine has done it occasionally, but I know when I've noticed it the noise is slack in the drive train - like if you're coasting and give just a little gas.

 

Are you accelerating hard and lifting foot? I've contemplated using a GoPro with a magnetic mount before when I heard or wondered what something was...

 

[cire0309]

I’ve noticed a clunk too when I go from coasting to light acceleration. I’m under the impression that the G80 causes that noise. My last truck was an Avalanche Z71, which also had a G80 and it did the same thing when going from coasting to light acceleration. It’s disconcerting, but I’m not sure if it’s actually damaging anything. I’d be interested to hear what comes about from your dealership though.

[SierraHD17]

Mine clunks too when I let off power and apply it again... has for a while ever since I... oh right... I put in a Detroit Locker and tossed the G80 hahaha.  

[cire0309]

I’m sure that drifting around the highway on-ramp is fun, but it gets old after a while. We always seem to get ice with our snow in Atlanta. I’ll take the Gov bomb, it’s been extremely reliable thus far in crappy conditions. 

[SierraHD17]

Who drifts..... need some serious driving lessons if that's the end result. I mean if an 18 year old girl can handle a 3/4 ton with a locker on icy highways with ease anyone should be able too.  And that was my 05 so it has no nannies to save you either.    Northern Alberta here and that means more winter and ice than summer lol.  Gov bombs are gov bombs and mine have reliably held down other lighter parts in the scrap metal bin lol.

[gearheadesw]

There’s going to be some thumping or clunking going from a no load situation to a loaded drive train. You’re going from literally one side of the gears to the other in the differentials. It’s drive line lash. Common in all vehicles. 

[Biggerdogg01]

I learned today that the noise that we are hearing in the drive train is coming from the transfer case. The sound resonates from the transfer case down the drive shaft, so it sounds like it is coming from the rear differential. It is normal.