What happens when the 5th nut fails on an nv4500? Loose 5th gear or everything?

5th gear slides back off of its splines and nothing happens. Usually there isn't any damage to any components.

So then you just loose the use of 5th gear? 

28 minutes ago, joecool911 said:

So then you just loose the use of 5th gear? 

Correct. Many "temporary" fix it by just removing the tail housing and slapping a new nut on it.

TFaoro is right it just slide back and no longer mesh with the other gear.

 

The other problem is most people can't tight it down to the correct torque no less too. So this why there is an issue with 5th gear nuts. Like with the updated shaft I learned it suppose to be torqued to 450 ft/lbs. I think the OEM shaft is somewhere in the 300 ft/lbs bracket.

 

I've seen a bunch of YouTube Redneck fixes including hammer and chisel or a pipe wrench to tighten the nut back on. Like most will say to upgrade the main shaft. If your going that far you might as well do fresh bearings and syncros. I've just went down this road with a rebuilt of the transmission.

 

 

I still have an automatic, but am looking into a change or a different truck. Was just wondering about the outcome of the more common issue with an NV4500.

It's not as common with the later trucks. The nut they used works pretty well. To keep mine on, I only shifted to 5th after 50mph.