03 2500 Suburban 4x4 prob

[jkhinch]

Hi, I have an 03 2500 4x4 with the 8.1 with around 225k miles on it. I've owned it for 4 years and approx. 50k miles.

I've replaced the transfer case (all but one of the bolts was missing!) and the 4x4 switch control (after the typical symptoms); both maybe 2 years ago.

Since I've had an intermittent issue where I cannot switch from 4wheel to 2wheel. I must (usually) move 4wheel to auto to 2 with rare exception.

But now I'm noticing more concerns:
*yesterday while parked I attempted to move from 4wheel to 2wheel directly. It worked, with a thunk that shook the vehicle. It felt kind of like with you move a gear shifter from park while parked on a hill w/out the e-brake on.
*we've had some snowy weather. I don't usually use auto 4x4, but I did this week and noticed something felt odd. Not odd enough for my wife to notice so who knows how long its been going on. It felt as though the 4x4 was kicking on and off. Not as it should, more like a constant off/on/off/on with a delay of only a handful of seconds between.
*Now I'm thinking running in 4x4 may be louder than in the past, but I can't tell if I'm just over analyzing and seeing ghosts at this point.
Thanks,

 

[zora]

see if this video applies to what you are experiencing

https://www.youtube.com/watch?v=qNQOt_JP78U

 

[jkhinch]

Thanks, I don't think so - I'm not stuck in 4wheel. I can consistently get back to 2wheel if I go 4wheel > auto > 2. Its actually been like that about 90% of the time for 2 winters, but without the issue I'm having in auto.

But - I've suspected the transfer case control module may be my culprit. Maybe I should start there...

Any idea if that control module is the same for my big block 2500 as with the smaller 2500 or 1500? I suppose that will be a quick answer from the scrap yard

 

[zora]

as you said the salvage yard should have an interchange guide or look it up here

http://www.tonkinonlineparts.com/productSearch.aspx?ukey_make=1086