Transfer case failure

[Goosewhole]

Good morning, y'all. A little background: I'm running a 2017 2500 4x4 CC LWB 6.7L Cummins, 68RFE automatic with 153,000 mi.
A few weeks ago, my truck started making this weird, whining/grinding noise from somewhere under/in front of the cab. I couldn't tell from where exactly, but it was very intermittent and it would just do it randomly. It would only do it while in motion, usually between 40 and 50 mph. I couldn't replicate it. The truck would do it when it wanted to, for maybe a second or two, then quit.
I never felt any loss in power, no jerking, just noise. It gradually started getting worse, so I had a friend look at it. The sound stumped him, but he said it sounded similar to a motor pulley sticking. I had another friend, who is a mechanic at a local dealership (wish I would've thought of him first), and on a drive, he had me shift transmission gears, thinking that might be it, but no, thank God.
What we discovered is that when it did it, it quit when I shift into and immediately out of 4HI. Eventually, it started grumbling in 4HI too, so I'm getting the transfer case replaced. I also found out my t case isn't electronic shift, and there were only three available in the nation, 80+ on backorder. I guess not really looking for advise, but if anyone hears a random noise from under the truck, try that.

 

[gofishn]

Thanks for the heads up on availability.

Do you have the specific transfer case Model you can share?

 

[Goosewhole]

Thanks for the heads up on availability.

Do you have the specific transfer case Model you can share?

Mine is the BW 44-47. I had to order it in from Colorado, and then UPS lost it, so I'm hoping they either find it quick, or refund my money quick so I can reorder one before I'm completely out of luck.
The BW 44-46 is the electronic version, which I understand is on most of the trucks now, but I couldn't speak for its availability.

 

[HEMIMANN]

I'm recalling the BW44-47 is the clutch case? Does your 4WD knob have the "auto" function on it? If yes, it's clutches. Possible you burned up a clutch in it. Which is why it needs an oil with friction modifier additives - there's info on this in synthetic oils if you search.

Guys with these have come up with oils that work with these without paying for MOPAR's "secret recipe" transfer case oil. There's nothing "secret" about wet clutches - only the right type and amount of friction modifier additive to allow the correct engagement lockup time span.

I have the BW44-46, which is the old chaincase, with added electronic engagement solenoid - but no wet clutches internal.

 

[Goosewhole]

I don't have a selector knob. Mine is the old school stick on the floor 4x4 shifter. I just have 4LO, N, 2HI, & 4HI.
What I did forget to mention in my original post is that another thread on a Ford forum that someone mentioned that their mechanic said that can happen from under-use of the 4x4 system, but take that with a grain of salt.

 

[HEMIMANN]

I don't have a selector knob. Mine is the old school stick on the floor 4x4 shifter. I just have 4LO, N, 2HI, & 4HI.
What I did forget to mention in my original post is that another thread on a Ford forum that someone mentioned that their mechanic said that can happen from under-use of the 4x4 system, but take that with a grain of salt.

Then you got an old timey chain drive transfer case. Any old ATF will do. I bought 2 more quarts than my transmission took and used those in the transfer case. I would have thought the higher numbered transfer case model would have had the newer "auto" clutches. Just google your model to be sure.

The only difference in the BW new and old chaincases is whether you engage with a stick shifter on the floor or push a button and an electronic solenoid engages. Same guts otherwise.

 

[Goosewhole]

My mechanic did fluid change and said a lot of stuff came out with it. But he's going to put the new transfer case on this weekend.

 

[GsRAM]

Sorry for your troubles. Question, did you ever service that transfer case or was that still the original factory fill?

 

[Goosewhole]

Sorry for your troubles. Question, did you ever service that transfer case or was that still the original factory fill?

Likely my own fault. I bought the truck used with 78,000, and I don't know if the dealer that sold it did it a service before they sold it, but I didn't. I was planning on it, but I'm sure I went way over the service miles. My mechanic is going to service the transmission when he switches the transfer cases.

 

[GsRAM]

Hey, stuff happens, I was just wondering as that could have contributed to the T cases demise... or I could have just been some kind of internal defect or abuse by the prior owner. Sometimes it's hard to tell.

I service the transmission (drop pan, change filters and refill, not a power flush), transfer case and both diffs every 5 years or 30k miles, whichever comes first.

My truck has 15k miles on it, but I did all of that and drained and flushed the radiator and overflow tank last year just before the 5 yr mark. It was due based on time for me, but I'm more particular than most. Hope they can get you back going soon