NV450 5speed blew at 184k miles.

[Doubletrouble]

 As the title reads, yes my 5 speed NV4500 ate itself at 184k. 

 Some quick background, I bought the truck used with 138k on the clock. 

 Now after some conversations with @Mopar1973Man I should have dumped the oil in everything on truck right away after purchase and replaced with new but i did not (now regretting it). I dont believe the fluid was ever changed. 

 Now, I have been searching for a rebuilder near me to get this done. I was thinking of doing it myself but decided it may be best to leave it to someone that knows these things better thatn i do. Ive never rebuilt one before. Problem is, i cant find anyone around me that does it anymore.

 So now my options are rebuild it myself or buy one online, have it shipped to me and install it. 

 There is more than just the trans that needs replaced now also.  Looks like the rear main seal on the engine is leaking, clutch throw out bearing was getting noisy before the trans blew as well and during removal of the transmission the mount fell apart.

 I have already received my replacement clutch, I went with a southbend clutch, single disk HD organic towing clutch good for 450hp and 900 lb/ft torque. This was a kit that comes with new flywheel w/pilot bearing installed, new bolts, disk and pressure plate and throw out bearing.

 I'll need a new transmission mount, new rear main.

 And now for what you've all been waiting for.......pics......

 

 

[JAG1]

I hope you do find a good guy to rebuild it. They're sometimes hard to find.

 

One thing... you got to stop towing cruise ships LOL!

[Great work!]

Almost looks like something went through the gears.

[Mopar1973Man]

Actually the factory fluid got thin allowed the hard facing on the gears to wear and then snaps a tooth off and cascade failure occurs.  One of the few reasons I switched to 50 weight gear lube. My last failure was the same two gears.

 

Here is even my input and countershaft gears. You can clearly see on mine the lower tooth has serious wear into the hardfacing.

 

Edited November 10, 2023 by Mopar1973Man

[Doubletrouble]

 @Mopar1973Man, how many miles on that failure?

 I believe it was an oil related issue. 

 Someone has been in this trans to some extent. The 5th gear nut is not factory, it's an aftermarket fix for the nut backing off. At least they didn't weld it! Lol I have pulled the 5th gear nut off yet to see if the main shaft was updated with a full spline shaft or not.  Hopefully today I'll get back to it. Been juggling this project with both my parents being in hospitals. Dad for a bad car accident and mom for other health reasons. Been a very busy couple weeks.

[Mopar1973Man]

Input gear has about 350k miles. 5th gear was about 300k miles. I've been only replacing damaged parts.

[JAG1]

21 hours ago, Mopar1973Man said:

Actually the factory fluid got thin allowed the hard facing on the gears to wear and then snaps a tooth off and cascade failure occurs.  One of the few reasons I switched to 50 weight gear lube. My last failure was the same two gears.

 

Here is even my input and countershaft gears. You can clearly see on mine the lower tooth has serious wear into the hardfacing.

 

It's strange how the large gear has every other tooth damaged all the way around. Never knew a pattern could show like that. My teeth are like that from old college girlfriends!

[Mopar1973Man]

Because the smaller input gear has wear through the hardfacing of the gear teeth which get brittle and snaps off. First place it goes is down on the countershaft and gets mashed up which now breaks those teeth. I'm of a believer that the factory lube is just too thin. Look up above 75w-85 is equal to 10w-30 engine oil. My 50 SAE trans mission fluid is 90 weight gear. Better high temperature protection when towing or working the truck hard. Just consider the viscosity off the oil at 200 or 220°F oil temperatures. 

Edited November 11, 2023 by Mopar1973Man

[Doubletrouble]

 Would lucus oil help in a manual transmission? 🤔  we've all seen these little demo things at the parts stores. I never ever once turned the handles though 

 

 

 

 I believe they make a gear oil additive as well. Just asking.......for a friend. Lol

[Max Tune]

It's thick like STP. I always play with that display. Think I'll start asking if they want to sell it to me.🤣🤣

[Mopar1973Man]

13 hours ago, Doubletrouble said:

 Would lucus oil help in a manual transmission? 🤔  we've all seen these little demo things at the parts stores. I never ever once turned the handles though 

 I believe they make a gear oil additive as well. Just asking.......for a friend. Lol

I would rather have a proper fluid than use a product that's too thin and have to add other products to protect the gears. Like Mobil 50 or Valvoline 50 is designed for Eaton Fuller 10 Speed manual transmissions used in over-the-road trucks. So, that would be like the PennzOil Syncromesh that people use which is actually too thin to make the GL-4 grade. In this case, people would be making up for the overly thin PennzOil Syncromech with Lucas additives. The more HP/TQ you make the thicker the fluids have to be to protect the gears teeth and the bearings. Thin fluids may be desired for smooth shifting and to this day I've not had a single issue with shift quality in my NV4500 running 50 SAE Transmission fluid. 

 

Then there is Valvoline 75w-90 which is rated both GL-4 and GL-5 which is a no-no why? Because GL-5 will cause damage to the syncros. 

[Doubletrouble]

 I was talking about the Lucas additive with the Mobile 50. Not to try to shore up the thin stuff. I was curious as to whether or not it would help the mobile 50 adhere the the gears better.

[Doubletrouble]

 Trans was definitely pulled at some point. Found a LUK clutch in there today. I pulled all the old clutch components off, removed the adapter plate and the rear seal plate. Seal is now changed, not installed on the engine yet though.

 The clutch that was in there shows some signs of extreme heat. I have seen worse but this is bad enough. Also, if you look closely at the friction disk and pressure plate it did not have full contact. Looks as if it may have had oil on the friction disk.

 

[Mopar1973Man]

3 hours ago, Doubletrouble said:

 I was talking about the Lucas additive with the Mobile 50. Not to try to shore up the thin stuff. I was curious as to whether or not it would help the mobile 50 adhere the the gears better.

Ummm... Might be careful making too thick...

[Max Tune]

That flywheel needs some attention or replaced. Looks like it's had a rough life....

[Doubletrouble]

 It will be replaced. The southbend kit I ordered comes with new flywheel.

[Doubletrouble]

 So how about an update.

I have the trans tore down, case is all but empty. Main shaft is 2/3 tore down. I ran into an issue removing the 3-4 syncro hub, it's a press fit on a splined shaft. I do not have a press, tried pulling it with a 3 jaw puller per the nv4500 service manual. That didn't work, the jaws are to thick to get behind just the hub. Time to find a suitable puller or borrow someone's press. (A friend has one a few miles away.)

 Once this hub is removed I will be able to begin the process of stacking everything onto the new main shaft. The one that came from the trans appears to be oem, only half splined 5th gear. It did have an aftermarket 5th gear nut on it with a pinch bolt. When I loosened the pinch bolt the nut itself was barely finger tight. This nut is supposed to be torqued to 280lbft. So sooner or later that would have failed also.

 Here's a few more pics of the destruction.

 

 

 

 

And some new parts.....

 

 

 

 

 

 Thus is the hub I need to remove to finish tear down on the main shaft.

 She's on there pretty tight it seems. 

 Once removed I have some cleaning to do in the case then install new bearing races, install the counter shaft, reverse gear idler and then begin reassembly of the main shaft. That way it keeps loose parts on the bench to a minimum. 

[Great work!]

I thick you could put a couple pieces of angle iron behind the hub and then support it over a bucket or barrel.  Then a few hits with a big soft hammer on the shaft end could do it.

 

I pick up bed frames on trash days they make great angle iron but they are harder to drill.

[Doubletrouble]

 Still haven't messed with the hub yet but I did clean up the case and install the countershaft and reverse idler gear. I began assembling the new main shaft from the output end. Once the stuck hub is off I'll be able to finish up the main shaft.

 I can get the bearing race out of the input shaft bearing retainer. Almost be cheaper to buy a new one than buy the tool to remove it. So that may happen.

 

 

 

Looks so Shiney and new!

[Mopar1973Man]

Very impressive job so far. PLEASE @Doubletrouble make sure you do a write-up for this I'm sure there are other NV4500 users who want to know how to do the rebuild and where you ordered your parts. 

Edited November 25, 2023 by Mopar1973Man