Be aware that even the upgraded super duper shaft fixes are failing, as well.
The problem is there's a lot of machining (potential stress riser points) in a very high load area.

I've known people to just re-install the gear and tighten on a new nut, and snap the mainshaft not too long afterward, so I don't subscribe to the idea that welding them weakens the mainshaft.

It's just a ridiculous design that was meant to make warranty and after that Dodge could have cared less.

Mark.

 

After 20K of driving in 4th, I finally dove in and did mine today with the newest style nut retainer. Mine had what appears to be the updated shaft, at least it was fully splined and had the new nut style. Anyway, I am gonna be sore for a few days, it beat me up pretty good with over tight bolts, rusted bolts, and generally the NV241DHD is a buggar to pull by yourself laying on your back. It is even worse to try and get back up there by yourself.

I am happy with the retainer design, took a wee bit of playing to make sure it would line up, but nothing too bad, I started about 280 Lb/Ft. and then just wet tighter a wee bit more until the pegs lined up.

One thing for sure, it is much nicer driving in 5th at Hwy speeds than in 4th.

 

I know you get what you pay for but has anyone tried one of the updated shaft kits off ebay. I can't put up a link to ebay but look for nv 4500 on ebay, there is a shop selling a shaft, 5 gear, all bearings, and blocker rings in a kit for 415$
My 4500 is getting a noise in 5th, so I'm sure before too long I'm only gonna be a 4 speed.