Help making a decision on truck purchase.

mkirsch wrote:
Keeping what you got isn't free.

I'm already off to a rip roaring start this year. Went to pull my trusty 2002 Silverado 3500 out of the barn, won't barely move. Bunch of transmission codes.

I think my 2015 Silverado 1500's torque converter is coming apart too. It's got the "shutter" that everyone posts about and it's right in that mileage range where the torque converters go bad. Just Saturday it started throwing a message "Service 4WD" and won't shift into 4x4.

Find a good trans shop now if it just started the shudder. My 2016 (same truck/trans as yours) did that for the first 60k of its life before coming apart.
I took the truck in with a couple thousand miles on it and told the dealer the TQ converter had an issue. Of course “cannot replicate” was the finding. Mine only did it under high load from a stop. Of course you can’t replicate that by driving an empty truck around the block…lol.
I’m all but certain the “shudder “ didn’t do any damage downstream until something finally came apart. Like I said, did it since new, never got appreciably worse, truck was horse whipped pretty hard in that 60k miles. Like bumper pull trailers in the 10-14k range flat peddled up n over the Cascades with 4-5000rpm grade braking comin down the other side.
Then one day it started acting up.
I never read about the issue much (company truck, didn’t care) but from a practical standpoint I’m 90% sure a new tq converter before it self destructed would have saved the trans without propagating more issues.
Hope this helps.

And the 4wd issue is likely unrelated (fortunately or unfortunately depending how you look at it).

Is your 02 an Alli or a 4L80? 100k miles maybe a bit more is a good/average lifespan for a 4L60/4L80.