Transfer case bad?

[mn_trailblazer]

I have a 2002 Chevy TB, I kept having an issue with my TCCM and the truck would act like it was in neutral while in drive, when it was bad and when I put it in the 4 wheel drive it made a severe bad clunk and shifted the truck when I switched it, I ended up driving it with a bad one for to long.
Since then I replaced the TCCM and now it drives just fine in 2HI, but I cant drive in any 4 wheel due to some sort of mechanical issue as follows:
I turn the vehicle on put it in neutral, change the switch to 4Hi and I hear the front motor shift but nothing underneath me sometimes I hear the underneath me one shift, I switch it to 4Lo and I hear a clunking thud underneath me and the front motor, I shift to reverse or drive and the truck jumps forward or back very heavily. I let my foot off the gas to roll in all modes but 2Hi and it does this weird stutter when rolling, not the RPM's just some sort of way it rolls, and sounds like the drivetrain is just going to fall out from beneath me, almost seems like its driving with a much of rocks somewhere in the system.
Any ideas, about to replace a bunch of suspension stuff but want this done first. Also when I mess with the switch sometimes when I turn the truck back on the selected mode has a blinking light with the N light up on the mode selector

[Eredin]

The N indicates neutral on the transfer case. However, all the modes usually only blink while engaging/changing. Sounds like the tcase motor may be getting hung, but I'm not familiar with it ever going to neutral automatically.

When was the last time it was serviced? Was Autotrak II used, if so? Good news is that you can generally get one from the junkyard for $200 with 100k miles or less. Just get fresh seals for it since it's out, if you go that route.

I'd put it in the air, put it in neutral and start rotating everything by hand. See how the rear and front driveshafts feel when in 2hi vs 4hi. Everything should move without binding.

[djthumper]

Take a look at the replies that you have received at GMTN as well.

[Glasscaster]

Your problem sounds familiar! Read through my thread, it sounds very similar to your issue.
Good luck, hope you get it sorted.
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