QUESTION: 1999 tahoe 5.7L vortec vin k automatic 4WD About 8 months ag…

QUESTION: 1999 tahoe 5.7L vortec vin k automatic 4WD About 8 months ago my transfer case took a crap. So i got one from my local U-PULL IT yard as i could not aford a rebuilt transfer case. I put the transfer case it and besides a really light ticking sound at low speeds of 10mph 0r less the truck drove great. Well today i warmed it up for 5 mins before taking my son to school as its below 20* outside. I got in the truck with my son, made it to the corner of my block, turned the corner and as soon as i turned the corner the truck had no power. It would not go more then 5mph and my rpms were at about 3000 / 3500. So i knew something was wrong. I was about 5 blocks from my house. I turned around to head back home and it seemed that after hold the gas pedal down for a few mins the truck kinds jumped and caught into gear and started to move but i backed off the gas as to not make problems worse. Made it home and parked it. I DID NOT try to see if reverse or any of the other gears besides 1st gear work as i had to get my son to school and was running late. Could the transfer case i got from the junk yard have took a crap on me also, or is this most definetly a TRANSMIASSION issue ? Also last summer my engine light came on for my oxygen sensor ( sensor 2 / bank 2 ) and i replaced the O2 sensor, but the code for it keeps coming back on and wont go away. ( pic for attention )

Richard OBrien: Can u manually shift it with gear shifter to atleast figure out what gears u have?

John P Berthel: I have not tried that yet. I have to wait till i get back home around 1pm

John P Berthel: But if all the other gears ( 2nd-3rd-R ) still work, that would not tell me if i lost 1st gear in trans or if my junk yard transfer case can be causing this.

Richard OBrien: You should feel the vehicle switch gears, I had a chevy and a ford that felt like it stuck in 1st gear with 4wd locked up but it wasnt locked in all the way try removing tcase motor and with trans in neutral running caulk wheels and switch it to high gear 4wd and play with it im sure youll find the issue. Also codes codes codes

William Alexander: Sounds to me like its the transmission.. Check for burnt fluid.. I had that same problem recently