...I nailed it off the line at a redlight and shifted to 3rd and nothing, tried 4th and heard a whirring sound but no grinding or other odd noises.

What did I do?

How much to repair and is it a DIY with standard tools?

Anybody have a 2001 NV4500 for a 4x4 in Texas or Lousiana?

 

I had the same thing happen to me. I hit it pretty hard after a green light, then "pop" it cameout of 3rd gear. I didnt have 4th after that either just 1,2, and 5. I talked to a couple of transmission guys and decided to get one off of a salvage yard instead of totally redoing my transmission, bearings, plates, gears, a whatever else needs replaced if your going to be rebuilding. My tranny was $1200. I had around 110,000 miles at the time.

 

Mack's Transmission in Houston said I probably broke the 3-4 shift rail. After looking at the FSM, maybe he was referring to the shift fork. If this is the only part that broke, it appears that I can drop the trans, pull the top cover and replace the fork.

Can anyone confirm this?

 

Also, would it be possible to remove the top cover if I removed the crossmember and lowere the transmission?

 

i broke a shift fork on my old chevy, and thats what i did to fix it, drop it (all the way out) pull the top replace the fork, put her back together, simple but not the easiest

 

Dropped the tcase and trans, pulled the top cover and all the forks and rails are intact and work. Put it in 3rd and 4th and turn the input shaft and I can prevent the yoke from turning. Something holding the gear sets together I guess.

I could not find any visible problem with the gears.

 

Dropped it off at the transmission shop this morning. They said that the input shaft gears and the mating gear probably stripped...150.00 for the pair. I had them price everything including a fully splined mainshaft for 275.00 and it came to less than a 1000.00 with tax. I will update the post once they have it apart. Hopefully there won't be any more broken parts.