4L80E rather.. I recently replaced this transfer case i have. it's a np 246 transfer case and it while in 4HI or 4LO it would grind gears and slip... sounded really bad. so... i got another for $450, i'm trying to see if i can fix this one and possibly make some of my money back. I took it mostly apart and I just can't find what's wrong with it. all the gears i can see are good. unless it's in the planetary... a bearing in there? I don't haven't went that far, looking for some advise/help at this point ... on what you think it is. i may need to rent/buy some special tools... I got a couple videos i just took of it, i hope it's good enough video to get a good idea.