I just started having an issue when I have my truck in 5th gear it runs fine until I let off the gas. As soon as it is coasting in gear it wants to pop out of gear. I've read about issues with the 5th gear bolt rattling loose. Could it be anything other than that? All the other gears run fine but it sure makes it hard hauling a trailer through Colorado without that gear.

2001 dodge 3500 quad can 4x2 5 speed no modifications right now.

 

Whats happening is the 5th gear retaining nut is working loose on the shaft and the gear itself is falling off the end of the shaft. Its not "falling" off but just so loose that the splines are no longer contacted. You may be able to continue driving it like that but I'd be cautious and STOP using 5th gear until this is fixed.

The 5th gear is the weakest link in the 4500. You can Google the problem with them and what you'll find out is lugging the engine in 5th gear and towing heavy in 5th gear is not recommended. The stress on the 5th gear and nut is aggravated even more when the throttle goes from ON to OFF or power to no power, because this causes the gear to rock on the shaft more. This is why you're finding that it drives until you let off the throttle.

There's many fixes which pertain to upgraded replacement retainer nut but the best and most costly fix is replacing the shaft with a fully splinned shaft.

 

Can I tack weld that bolt in place? Or do I just have to have it tightened every time it decides to come loose?

 

There's various ways to "fix" it. Aftermarket and even dealers have upgraded nuts available which come in different styles depending on the nut design. The upgrade nuts are the most popular as obviously its much easier than removing the transfer case if the truck is a 4wd. In saying that, using red Loctite is highly suggested in combination with the upgraded nut design. Will its stay?..... That depends on driving habits and how bad the splines and gear are worn from when it came loose prior. Generally guys can get the nut to last awhile.

Then there's the shade tree guys who try to weld the nut back on. Not advised as not only will this definitely break loose but you also compromise the gear and shaft metallurgy. Some people have tried just cleaning things up and reinstalling the factory nut with red Loctite. Its not as good as the upgraded nut but I guess whatever you chose depends on how often you're OK with pulling things apart if it doesnt hold.

Here's a place who knows all about the 5th gear: http://www.quad4x4.com/NV4500%205th%...0Solutions.htm

These guys claim to have the permanent fix but I've heard of this product creating other tranny case failures as a result of, so I wouldn't use it. http://fifthgearrepair.com/nv4500repair.html

 

Katoom, can you elaborate on the case failures? I haven't heard of any, nor can I see how it could possibly cause a case failure, unless somehow you had the assembly too long and tried to pull it together with bolts.

For his trans, it won't matter, the retainer won't work on a 2WD trans.

 

Ah..... I didnt notice he had a 2wd so cmats you can disregard that second website I linked.

As for the failures, all I can say is that in a few years ago when this design came about there was a lot of talk on the forums. Not fully understanding how it was a "permanent" fix, there was plenty opinions on both sides of the fence. But because no one really had any knowledge or long term experience, the topic was dropped until someone had reason to post an update. In saying that, it was probably around a year ago someone on some forum posted a thread whereby showing that the fix device actually shoved its way into either the tranny housing or the transfer case housing. Dont remember which one but it was because of thrust movement. Sorry but I dont have a lot to elaborate on as the thread came and went pretty fast. I'll see if I can find it for you.

 

Here it is: http://www.cumminsforum.com/forum/98...pair-junk.html

 

Ok, yea, I can see huge issues if you manage to shear the retaining legs off, the nut backing off would have no place to go but back into the transfer case.

I gotta think about that one for a bit, I am not too concerned yet because I don't haul heavy like that dude did.

I just can't fathom how he would have sheared the legs off.........

 

+1 to Katoom. I would avoid welding if possible. Using a pinch welder to modify the retaining nut to a interference thread lock nut would have a similar effect without annealing the shaft like a weld would.

I'm used to dealing with japanese transmissions in which this issue is unheard of. The difference with the 5th on Aisin transmissions for instance, is that the gear splines are much longer so that the deflection form the bevel of the gear is unable to cause the gear to deflect and wiggle against the retaining nut. It can slide, but stays square with the shaft due to the length. Not a strength issue, just a wiggle issue. Without having dealt with it on the 4500, my knee jerk reaction would be to loc-tite-red the splines to resist this relatively mild deflection force. *If* it doesn't wiggle, it won't work at the nut. A proper puller will be required to pull 5th in the future though.

 

I really dont know what to say. It seems like a plausible idea. You know how it goes though..... Once you hear of a failure then all credibility seems to go out the window.
Here's a couple pictures on this forum of how it fits. I have to admit that it looks like its a functional concept. http://www.cumminsforum.com/forum/98...-nv4500-5.html