Hello All. Just had a horrifying experience where I thought my tranny was a goner, but wanted to happily report that it was an electronic issue. I'm also not sure how or why it's fixed, but here's what happened.
Problem: Extreme grinding in reverse and won't move. (Will move forward in all gears with no grinding or other issues.) "VDC off" light illuminated on the dash and the console switch for the VDC to turn it back on failed to do anything. Also the digital visual on the dash next to the odometer for the 4x4 showed up during the self test when first starting up, but would "disappear" once the dash test completed.
Cause: Boyfriend had hooked up a trailer and proceeded to turn the dash switch to 4x4 LOW directly without moving into it slowly by letting the transfer case catch up. He also did this while in "drive". He then put it in Reverse and from inside the house I could hear this awful painful screaming (oh wait, that was me) I mean awful painful grinding noise.
Solution: After consulting an expert on JustAnswer.com, he told me that it was the 'Sun Gear' or the "Carrier Shell" and that either way, the transmission would have to be rebuilt. Since I've been around cars my whole life and never heard of that, I didn't believe him. In fact the part names sounded so hokey, I called Nissan parts...and there is in fact a "sun gear" at a mere cost of $385. I still wasn't convinced it was mechanical. I went back out and pulled all of the relays. I checked all of the fuses. I got sidetracked, and came out about an hour later. I put all the fuses and relays back in and in accordance with some other posts, I put it in neutral and turned the switch back to 2x4. I started it while in neutral and saw the dash lights "self test", then the "VDC Off" dummy light went OFF and then the wonderful little picture of my 4x4 wheels next to the odometer STAYED ON! Woohoo! I then put it in reverse and held my breath. It worked beautifully.
Lessons: #1 Don't let Boyfriend do ANYTHING with my 2004 Titan. #2 Don't believe the first expert I consult. #3 Trust my instincts and hold my breath #4 When in doubt, pull relays, fuses or battery...and pray.
I saved myself a towing bill, a diagnostic check and a lot of time by just trying the "Fonzy method". I am considering trading this in now, but at 170k miles...it's hard to part ways.