Jump to content

Possible 5th gear nut fix for the NV4500.


Recommended Posts

Here is a link to a transmission shop that is claiming they invented it. http://fifthgearrepair.com/nv4500repair.html Does this only happen to 4x4 NV4500's? No one ever seems to mention two wheel drive NV4500's...

I've looked at that site before, and I was wondering if it would work on a 2 wheel drive. That website makes it sound like only the 4x4's have the 5th gear problem...
Link to comment
Share on other sites

Yes it's for 4wd only, yes the tail housing is the issue, yes it happens to the 2wd ones, mine does it every 100k miles since I have never done anything permanent to fix it. After it initially happens, it just comes off easily from that point on if all you do is retighten the nut. Since my truck was used as a hotshotter and he pulled in 5th gear a lot, it quickly ripped the nut right off. I imagine a normal driver wouldn't have any issues till 200k or possibly never.

Link to comment
Share on other sites

So far so good with mine also. The rear seal is starting to weep just a little. Not enough to drip oil, but just enought to have some residue. I wonder if pulling off the tail housing to change the seal, then pull the nut off, clean everything, lock tight the heck out of it, put it back on would be good preventaive medicine? It seems like after it comes off that is the point of no return as far as a simple fix is concerned. Perhaps getting ahead of the game would be a good plan.

Link to comment
Share on other sites

So far so good with mine also. The rear seal is starting to weep just a little. Not enough to drip oil, but just enought to have some residue. I wonder if pulling off the tail housing to change the seal, then pull the nut off, clean everything, lock tight the heck out of it, put it back on would be good preventaive medicine? It seems like after it comes off that is the point of no return as far as a simple fix is concerned. Perhaps getting ahead of the game would be a good plan.

I wouldn't touch it.. When it goes, you just put it in 4th gear, it doesn't leave you stranded or anything. The gear just slides off the splines and spins on the shaft. You can actually feel if it is loosening up. When you let off the clutch the engine is dragging on the gear, when you push the pedal you load the gear so it twists the other way and there is a certain amount of give/play in it. As the nut works it's way off, that "play" gets wider and wider because the nut has unscrewed and since the gear is helical, it slides down the shaft then hits the nut then "engages" on the splines. When I screw the nut back on, there is almost no play in it. It should be the same as all the other gears basically.. But yeah, don't fix what aint broke... I think the 24V trucks have a revised nut and that initial tightening and other tightening screws on the nut seem to "set" the nut in place and keep it there a long time. It's a very very complex issue that nobody has been able to really pinpoint. In my opinion it is the play that works the nut off. As in letting off and then getting back into it, working from loaded to unloaded gearing, hammering at that nut. That is why even tack welds break loose. Thing is, as with anything else, I don't know which of these rumors are from guys doing truck pulls and guys who just pull a TT every now and then. Many forums combine the 2 then you have guys with billet everything because they saw it break on a guys truck. The rumors never drag along facts like the guy popping the clutch with 50psi of boost or this or that. Meaning, tack welds might actually work.. I am very easy on the clutch and only punch it once it is engaged and I am already slightly loading the engine, I don't want to floor it and slam everything with the play in the gears, I want them to already be meshed. Be sane, stuff won't break :thumb1:
  • Like 1
Link to comment
Share on other sites

Here is a link to a transmission shop that is claiming they invented it. http://fifthgearrepair.com/nv4500repair.htmlDoes this only happen to 4x4 NV4500's? No one ever seems to mention two wheel drive NV4500's...

That's where I got mine........and yes, it only works on the 4x4 trucks.

I have approx 30k on the repair and it seems to be holding up well so far. When I tow, I drag 8k-13k.......went from PA to UT and back in April and had no issues. And I don't hesitate to tow in 5th gear.

- - - Updated - - -

Be sane, stuff won't break

This is generally true.......though when mine popped off I was just driving down the interstate with no trailer and no load. And there were no warning signs prior to the failure.

As I understand it, the only true reliable repair is a full-spline main shaft. But my reasoning was that for $150, the retaining sleeve was a decent alternative to the cost (in time and money.....because if you tear it down that far, you may as well rebuild) of tearing down the trans to install a new mainshaft. And if the repair failed, I'd only be out $150 and a little time.......

Link to comment
Share on other sites

×
×
  • Create New...