All-in-all a great vehicle, though it had some problems. Bought vehicle w/115K miles in 2009 and got rid of recently when the tranny went kaput at 186K miles. Put about $3,500 in repairs. Biggest problems (other than the tranny) were the EGR & fuel pump (typical for Chevy trucks), ball joints and A/C compressor. Smaller items were heater control valve leaking and misc items breaking/failing. Can't complain though for a 16 year-old truck. Just make sure to purchase a Tahoe that hasn't towed a bigger trailer or boat (my mistake with this Tahoe). 2WD was very good in heavy winter snow. 4x4 was virtually unstoppable. The Chevy 350 will run forever without a problem if normal maintenance is done
The Chevy 350 Gen I engine is arguably the best engine ever made. Its durability, reliability and longevity (40 yrs of being built) is as good if not better than the best Japanese and German engines ever made. As long as general maintenance is done and the engine isn't beat on too hard, the Chevy 350 should easily get to 350K miles without major repair. At 186K miles, my Chevy 350 didn't burn a drop of oil or antifreeze and didn't leak at all. It ran like it had 30K miles on it.
If you need a safe winter vehicle to get you somewhere in the worst winter conditions, look to the Tahoe. Because of its weight and shorter wheelbase, the Tahoe is virtually unstoppable in 4x4 mode.
Watch out for the tranny. This generation of Chevy trucks (Tahoe, Suburban, C/K 1500 pickup) has a notoriety of the tranny going out anywhere from 140K to 200K mi., depending on how the truck was used. Best to look for one without a trailer hitch (usually means no heavy hauling/abuse was done). Tranny will cost you between $1,500 and $3,000 to replace.
The only other costly repairs unique to this vehicle are the EGR value ($250-$350) and the fuel pump ($350-$500). Ball joints ($600-$850) will go out on pretty much every 4x4 after 150K miles. A/C compressor ($600-$850) will go out, but this can happen with any car/truck/van over 10 years old.