2019 K1500 Transfer case issue.

[dfarr67]

Got the company truck service today and they said the transfer case oil was burnt. Lots of highway miles and I do use 4x4 in the winter and on the gravel, I use 'auto' sparingly- I either want 4x4 NOW or 2wd is fine. Is there an issue with these cases? I do look after my gear as the out of the way places I go may be inconvenient for a breakdown. 2019 K1500LD, 5.3L auto.

 

[Greasymechtech]

What fluid? and km?

 

[D60]

The NP261s and 263s in GMT800s had an inexplicable problem with boiling off their ATF. I've never seen an explanation for it, although I had found ATRA or ATSG articles claiming it was being researched.

The fix there was to run 5W-20, which I did after finding it dry one day (nope, it wasn't pump rub)

If you have "auto" you theoretically need AutoTrak or whatever specialty fluid GM calls out in '19, so you can't just go to a light motor oil.

What exactly made them say "burnt?" Smell? T-case fluid often turns dark with mileage, likely more so in a 'case with clutches for Auto. Plus, I don't know what color the current spec is but AutoTrak II is blue. Point being if they're going off color they could be confused??

 

[dfarr67]

124k kms, they said it was a dark colour. I was surprised it was red fluid- I assume dex. Starting to make some noises as well. They didn't say if it was low- and I'm always on the lookout for leaks.

 

[D60]

124k kms, they said it was a dark colour. I was surprised it was red fluid- I assume dex. Starting to make some noises as well. They didn't say if it was low- and I'm always on the lookout for leaks.

Yeah the best I can tell they went Dex VI across the board '14-19 so red would be normal.

Any t-case I've drained with some mileage on it the fluid is dark. That alone wouldn't make me think "burnt"

 

[Greasymechtech]

Normal for neglected fluid

Change it out more often

 

[350Rocket]

Got the company truck service today and they said the transfer case oil was burnt. Lots of highway miles and I do use 4x4 in the winter and on the gravel, I use 'auto' sparingly- I either want 4x4 NOW or 2wd is fine. Is there an issue with these cases? I do look after my gear as the out of the way places I go may be inconvenient for a breakdown. 2019 K1500LD, 5.3L auto.

I don't know about the newer ones...but I was told using auto on my 2005 gmt800 could accelerate the pump tub issue causing the case to wear through and leak. Only issue I had was clunking pulling away from a stop but it went away with a fluid change. The fluid never got extremely bad looking though.

 

[D60]

I don't know about the newer ones...but I was told using auto on my 2005 gmt800 could accelerate the pump tub issue causing the case to wear through and leak. Only issue I had was clunking pulling away from a stop but it went away with a fluid change. The fluid never got extremely bad looking though.

Having been into an NP246 in our old '05 Yukon and becoming way, way more intimately familiar with it than I ever wanted.....I can see no reason Auto would accelerate pump rub.

I even bought the Kent Moore tool to set height of the clutch basket (and replaced all clutches). Like I said, way more than I had intended to get into (sigh).

Oh and I was missing the "addendum" tool for the later years (which applied to '05) so I simply machined one because it turned out to be nothing more than a .200" thick Jo block basically

Wait, what were we talking about??? I'm reliving past trauma....

 

[350Rocket]

Having been into an NP246 in our old '05 Yukon and becoming way, way more intimately familiar with it than I ever wanted.....I can see no reason Auto would accelerate pump rub.

I even bought the Kent Moore tool to set height of the clutch basket (and replaced all clutches). Like I said, way more than I had intended to get into (sigh).

Oh and I was missing the "addendum" tool for the later years (which applied to '05) so I simply machined one because it turned out to be nothing more than a .200" thick Jo block basically

Wait, what were we talking about??? I'm reliving past trauma....

It was just something I'd heard, probably a myth. I used it a few times years ago before I bought the truck (company truck). I found using 4 auto would kick in the front too abruptly when the back lost traction and it would jerk you back in the seat. I found it better just to use 4hi if it's really snowy or 2 in minor snow. Don't know if it's just mine that's like that, but it shifts into all ranges including 4 Low quickly and smoothly. I can barely even hear it, though low makes a small noise when it goes in or out.
I think we were talking about transfer cases but we might have derailed from the correct track.