I'm not here to re-hash the whole 5th gear lost, question and fixes, nor am I looking to replace the main shaft in my NV4500. I lost 5th at 138K and drove the remaining 260 miles home in 4th. The truck is bone stock, and rarely tows these days.

That said, I am looking for owner experience with which nut has the best chance of holding when replaced with a new nut, not welded, but replaced with Loctite 263 or Permatex Red, and torqued to 280 ft/lbs.
I plan to:
- replace the 5th gear to help reduce at least some of the spline wear if present.
- replace the gear nut. Which one shows the best result for holding the longest. I have seen several mentioned, but see little history on how well they work.
- May consider the nut engaging/locking sleeve. How is its history for holding w/o breaking the four lugs?

Looking at the new style split nut with clamping screw; the one with two set screws, or the one with three set screws with brass pucks.

Thanks for knowledgeable responses

 

I installed the retainer from Active Transmission & Gear and mine hasn't come loose. I beat that transmission like it owes me money and I'm usually in 5th gear early, too.

 

Thanks, I will search them and look into it. I didn't abuse it, heaviest pull was a 30ft travel trailer (2k mi using 5th) about 5 yrs. ago. Also, always tended to get into 5th gear pretty early, likely too early. Thanks again Beard

 

We've been using one with the 2 brass pucks and set screws which comes with a strip of factory loctite. Knock on wood, done quite a few with no come backs.

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No sweat, brother.

 

MysteryNC, thanks for the input. Hope you continue to get no come-backs.

 

MysteryNC,
Would you mind providing a source for the nut that you use that has the two brass pucks?

Have you had any experience or feedback on the nut that has 3 brass inserts contoured (with threads matching the nut) and 3 set screws? If yes and good, a source please?

I have pulled the 5th gear out and cleaned it, it shows signs of slight wear inside the gear at the splines mating area. I was thinking I would replace the gear to reduce some of the wear between main shaft and gear. Any thoughts?

Thanks,

 

Thanks for all of the input from this great forum, and a special thank you to Mr. MysteryNC.
From the input I received, I'll be putting it back with a new gear, new style locknut with two set screws with pucks, Loctite primer, and Loctite 272 permanent threadlocker.
I'll post again as the project is completed, then I'll try to post as the miles accumulate.

 

Well she's done, and hopefully for a long time. Slow in getting it done, but I am retired so luckily I could wait for parts, weather, etc.

Again, a thank you to mysterync for some excellent input and sources.

I didn't want to pull the trans and change the shaft so I took the option of:
1) replacing the fifth gear to reduce the fretting wear.
2) put the gear back with plenty of Loctite 272, and good or bad, I applied sleeve retainer to the shaft and gear splines.
3) Cleaned, cleaned and re-cleaned ALL splines and threads to eliminate any oils, using Brakleen. Prepped the gear and shaft with Loctite Primer/actuator.
4) Assembled the nut (with red 272) and torqued to 295+ ft/lbs. I used the new nut with 2 set screws and brass pucks. As a side note, I put the trans in 1st gear and was able to torque to the 295+ w/o using the splined shaft holding socket, the engine held it.
5) Torqued or attempted to torque the set screws to 10 ft/lbs, but twisted off two Torx bits. After a bit of working to get the broken bit out, I wised up. Rotate the shaft so that the set screw points down, tap the nut lightly with a hammer, and the vibration brought the piece out (both times). I torqued them to who knows what, using a good allen style wrench and pliers for leverage. These also got the red 272.
6) Replacing cross-member was a major PITA for me. I read of someone using a hydraulic jack horizontally to spread the frame rails a little, but mine was busy holding up the tranny. I wedged a 2x4 between the rails with a sledge, this may have helped some. To aid in getting the cross-member in place I moved it slightly rearward and used a floor jack to hold it in place, and with a bit of persuasion with a sledge and 2x4 block, it is in place.
7) Filled trans with Pennzoil SyncroMesh and the transfer case with Castrol torqmax ATF+4.
** I'm going to try not to lug it in fifth, only 5th about 1500 rpm (I hear).

I'll try to post some mileage as time goes by, to give a history for this method.
It is not a daily driver or a long hauler, so it might take a while.

 

Sounds like you did a A+ job. I think the sleeve compound will give some added protection! I usually don't pull the cross member and work around it. Glad you got it fixed, glad I was able to help out.

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