Engine/Transmission (1998.5 - 2002) NV4500 whining - now broken bolt

[M Campbell]

Hi all,

Well, I ordered the new 5th nut and the tools to fix my (supposed) 5th gear problem. I was getting a whining noise that has been increasing over the last 10k miles. I put the truck in my garage, drained the trans fluid (I'd just changed that 6k miles ago) and saw lots of gold and silver specs all through the oil:

uh-oh. Separated the transfer and tail housing from the trans and looked at the nut. The nut and gear both looked/felt tight. I turned the output shaft by hand and it was smooth for half a rotation and then felt "notchy" for half. I got a flashlight and looked into the trans... lots of metal particles there---a whole layer of metallic sludge in the bottom of the case. Looked some more and recovered half a bolt! About a minute later I discovered where it had come from. It was one of the four bolts that hold the output bearing retainer plate onto the back of the trans. The other half is still in the trans, broken off pretty much flush with the case. I'm thinking it was either a bad bolt or the person who did the assembly over-torqued it and twisted it pretty much to failure before having another sip of coffee and sending it down the line. I can see where the bolt has been ground around in the case chunking some aluminum off of the tail housing as it went. Probably some gear damage in there too. And of course all the bearings/synchros have been running in metal particles for at least 10k.



I went to the dealer this morning and took the bolt head in. I thought maybe they'd be interested in helping me out, as I only have 44k on the truck. Uh, no. They said they have to cotact the DM (?) and get back to me...



So, looks like I'm replacing the NV4500 in my '99, 44k mile truck that's about half paid for... thanks New Venture.



Does anyone have a contact at New Venture Gear? I'd like to email the pics and at least let someone there know that this happened...



I'll be putting a call into Blumenthal and Standard to see what my options are in a bit.



As always, thanks for any comments/advice/consoling sob stories you can offer.



Mike

 

[emjay]

Speckled gear sludge in of itself is not necessarily a problem. If the gear teeth are not cracked or broken, I'd just replace the soft parts, and any bearings that have cracked or chipped races/balls/rollers.



Did you inspect each gear carefully?

 

[M Campbell]

Emjay, good point about only replacing soft parts. I think I'm going to have Blumenthal Mfg. do a rebuild. They will inspect everything closely after it has been cleaned up (I didn't see any chips, but was only looking through the PTO cover with a trouble light). Sounds like they'll do all bearings, seals, synchros, and fully splined mainshaft with 5th for about $900 including shipping. Of course, if I need gears it'll cost more. Since the bearing and seal kit is $159 for everything I think I'll just have them replace all the bearings with new. I'll also swap out the pilot bearing for an oilite bushing while I'm there. I'm thinking the transfer is probably ok due to the seal between the two - I don't think I saw any metal when I drained that, but I'll have to check the pan again. Have I forgotten anything?

 

[emjay]

It's always a good idea to replace inexpensive parts while it's apart, sounds like that what you're doing. I know nothing about the company that you're taking it to, but here's a couple of general suggestions:



1. Get the old parts back, especially gears and bearings.



2. Ask them what type of bearings they use -- should be whatever the OEM uses, or Timken or BCA, or other reputable US mfg. -- no chinese or japanese equvalents; I've seen "equivalent" bearings used on Muncie 4 speed input shafts that split the outer race under harsh conditions, because the "equivalent" bearing had fewer ball bearings.

 

[M Campbell]

Oh, yeah, I didn't think about "equivalent" bearings. I'll ask about that specifically when I talk to them again. Their site is www.blumenthalmfg.com Seems like a huge place - a dozen buildings and over 200,000 sq. foot facility. They do light, med, heavy duty over-the-road and off-highway stuff. Even have a dyno for manuals. They have NVG listed as a supplier so hopefully they use their parts. I could be wrong, but I think I read that they were the first with the fully spined shaft, so it seems that they have a lot of experience with this trans.



Thanks,

Mike

 

[John Berger]

I would definitely replace all of the soft parts while the transmission is off the truck. I recently had the fully splined mainshaft installed while I was getting the input shaft replaced under warranty. I was told that internally, the transmission looked very good so I didn't replace any of the soft stuff or bearings. I hope it doesn't bite me in the a$$ at a later date. If I had it to do over, I would go with replacement.

 

[TPlasek]

I had the same bearing go out on my 4500 with 90k on it. I had the same whine you were talking about, but my retainer bolts were still in. The bearing just fell apart (Don't even get me started of the factory Castrol lube). I changed the bearings, synchros, main shaft, and fifth gear. Now it still has a slight whine to it. Not sure what I missed, but it hasn't become any louder, even when towing.



After I pulled the transmission apart, I saw, mechanically, how fragile 5th gear is. I use it a lot less now in heavy uphill situations. 5th gear almost looks like an afterthought for that transmission.