I follow what you're saying. In other words, the double nuts tacked together is only as good as the splined mainshaft & 5th gear nut assembly.

Local shop that repairs NV4500 noticed the same problem with the shafts & gears they were using. They switched to a different vendor. Now, they heat the gear and press it in place. No more returns.


lgp9999
good job

 

Excellent write up on 5th gear failure http://quad4x4.com/NV4500%205th%20Ge...0Solutions.htm

 

Not lugging below 60 MPH in 5th gear will help more. Splines full length on shaft will help much also. Never weld to nut to shaft...

 

Just to add, mine came off at 65mph pulling 12k lbs. up a slight incline.

Also, traveling just under 60 in 4th gear is really revving it for those of us who have 4.10s.

 

Well I'm driving it and lovin' it! It's working perfectly so far!

BTW, with the Castrol Syntorq the tranny always had a bit of a hum... not a bad hum, just a hum of gears meshing together. Now that I put in Amsoil gear lube it is totally silent.

 

I agree with him (GAmes). I had the 5th gear problem a few years ago and after all the research, I went with a fully splined main shaft and it has been good since. When you get to the point where you have your first failure you have now worn the splines themselfs and because of this alone will accelerate the problem again because the 5th gear is able to rock on the splines. Good work and I hope I am wrong!

 

lgp999:

What was the thread size?

I need to fix my 5th gear, and I would like to try the same thing.

Unless you machinist buddy made 2 sets.......

 

The thread pitch is 18 threads per inch, however when we mic'd the threaded portion it was not a normal size... somewhere around 1.67" IIRC.

He still has the CNC file to make the nuts with, however it might be kind of expensive. The two of them took a few hours to make, including having to do some hand trimming with the band saw between a couple of stages of milling. This includes chamfering the edges for better weld penetration. Then he's gotta make the wrench.

It would probably be more cost efficient just to order a couple of nuts and a wrench for them, but I needed them that day and he owed me a favor. If you're totally set at going this route (I can almost guarantee that the factory nuts are not of a material that's as hard as 4140) I can check with him.

 

I have a essentially the same rig as yours and I lost my fifth gear during the early Spring 2007 and have been riding around with only four gears since. Did you perform this modification because you had no fifth gear?

Thanks,
Chuck

 

Why not just weld the nut to the shaft?

 

67HR, by welding on the shaft you create a point to fail.

 

Infidel, in the article they state that if you have over 150,000 miles, and you haven't had 5th gear failure (yet) they don't even recommend their kit, they recommend you rebuild your transmission!
And if you've already had 5th gear failure, they say they won't even sell you the kit, because the splines have worn too much.

So are all of the other fixes still just "temporary"?
if so, about many miles?

 

Yes, it's very common. Take a look at the quad4x4.com link that was posted above.

 

Hey, per my post about the quad 4x4 link,

Did I mis read it, as I stated in my last post?
I mean, I didn't get that there was an easy fix that would help me with 185K miles, even though I haven't lost my 5th....did I miss something?

 

I also look at it this way, Quad is trying to sell a product too. Whats the difference between a tranny with 149k and 151k? Very little, if anything. Is a rebuild gonna hurt anything? No? Is it neccesary? Maybe, maybe not. Thats a judgement call. JMO.