Engine/Transmission (1994 - 1998) NV4500 Noise.....Yep another one of those 5 speed issues.

[moparguy]

I do apologize for bringing up one of the most discussed old issues possible, but my 1995,3500 truck with 250,000 miles has transmission problems.

The history is, As a preventative measure (about 100,000 miles ago) I had the NV4500 in the 95 freshened up and a fully splined mainshaft installed by Standard Transmission in Ft. Worth. The truck had about 150k on it at the time and everything was fine, it's just that 5th gear is a known issue and I didn't want to deal with it coming off while pulling a 10,000 trailer thru the Rockies.

Well, all's been great until the past few hundred miles with a noise that's getting louder with the miles.

Key details:

1. Noise in not a harsh failed bearing noise, its more a lower frequency sorta swishing sound.
2. Does not do it in 4th, all other gears, yes.
3. Changed the Amsoil purchased about 10k ago from Standard Trans to Syntork and it shifted better, but no change in the noise.
4. As a test for a bad bearing I pulled the shifter and added a quart of Lucas oil additive. Purpose was to see if the increased viscosity made a difference. It did not.
5. It shifts fine, just the noise issue. Not loud but easy to hear.

I've pretty much parked the truck till I can pull the transmission. Haven't decided if I'll take it apart looking for a problem or just run it down to Ft.Worth and let Standard Transmission go into it.

Anyone have any insight on what may be going on?

Thanks in advance, Ron

 

[SAndreasen]

Well these things are a little noisy especially with more miles but if it just started something Is up for sure I've been into a lot of nv4500 but without seeing it I can't really make a guess i wonder if it's something in the clutch maybe ? When you drained the oil was it clean and no particles ?

 

[moparguy]

Well these things are a little noisy especially with more miles but if it just started something Is up for sure I've been into a lot of nv4500 but without seeing it I can't really make a guess i wonder if it's something in the clutch maybe ? When you drained the oil was it clean and no particles ?

It did start all at once. My hearing isn't that great these days (25% high frequency hearing loss) but it's gone from "am I hearing something" to the wife saying "what's that noise) in the last 500 miles.

Only thing in the oil was the normal brass from syncros, no steel flakes or pieces. I did wipe out the case and feel around looking for pieces of bearings and nothing.

I think the fact that it's no noise in 4th rules out clutch/throwout and input shaft bearing noise. Would it also take the final output shaft bearing out of the picture? I really don't see how in just thinking about it, but a bud suggested that may be the problem. Since I've never been into a 4500 I'm not able to see how.

Ron

 

[GrantP]

I could be completely wrong on this but I don't think the countershaft is spinning when you're in fourth so that's likely where the problem is. It's worth a phone call to Standard Transmission to ask them about this. Either way I think the trans is coming out for another rebuild...

 

[BigPapa]

I'm with Grant.

 

[NIsaacs]

I could be completely wrong on this but I don't think the countershaft is spinning when you're in fourth

The counter shaft always spins when the inputs shaft is, just no torque on it in 4th. The one bearing that stops in 4th, is the pocket bearing so that might be the noise.

Nick

 

[moparguy]

The counter shaft always spins when the inputs shaft is, just no torque on it in 4th. The one bearing that stops in 4th, is the pocket bearing so that might be the noise.

Nick

Nick, are you referring to the pocket bearing on the output side of the input shaft? If so I'm guessing/hoping that can be changed by just pulling the input shaft? Possibly the top cover as well.

If the above is the case and on inspection the pocket bearing is bad, that'd be the best of all possibilities for sure.

Thanks, Ron

 

[moparguy]

Found this on another site http://www.cumminsforum.com/forum/94-98-drivetrain-except-engine/516911-diy-nv4500-rebuild-information.html

The best how-to on diy rebuild of NV4500 I've found. Shows the pocket bearing to be where I thought it was located. It'll be a few days till I pull the transmission and see what's going, not a project I'm looking forward too.

 

[GAmes]

I replaced my NV4500 12 times before I upgraded to the G56. The first time was the 5th gear coming off, the next 11 were failures of various magnitudes. I can tell you from experience that once they start making noise failure is imminent. The longer you listen to it, the more expensive it will be.

 

[SAndreasen]

www.quad4x4.com
Is the best place to get parts more money but i would not trust anybody else for quality parts if you want to do it once and be done With it

 

[SAndreasen]

www.quad4x4.com
Is the best place to get parts more money but i would not trust anybody else for quality parts if you want to do it once and be done With it

 

[moparguy]

Well, trans is out and searching for info to help in deciding which shop to take it too. I'm is south central Arkansas and leaning toward Standard Transmission in Ft. Worth, also considering High Gear Transmission in Memphis, Tn.

 

[BigPapa]

Go with Standard.

 

[moparguy]

To close this chapter, dropped the transmission off at Standard Transmission at noon last week, picked it up the next morning. My instructions were do whatever it took but, call me if it looked like the cost was going north of $1,000.00.

No call and picked it up the next morning. Total cost was $602.00 for a full bearing kit with new 5th gear nut and 5th gear shift rail (already had the fully splined mainshaft).

I didn't talk to the tech but did request the old parts. When I got home and examined the old parts I found the front countershaft bearing race (USA made Timken bearing) was galled on about a third of its circumference.

The 5th gear shift rail did show a bit of wear. All the other parts looked good to run with 100k on them.

Just finished putting the truck back together with a new Mopar throwout bearing and haven't driven it yet but feel good that the noise issue will be solved.

Ron

 

[SAndreasen]

Let us know how it lasts I've put a couple cheap nv4500 in and they last about a week past warranty . Did they do new synchronizers I hope

 

[moparguy]

Let us know how it lasts I've put a couple cheap nv4500 in and they last about a week past warranty . Did they do new synchronizers I hope

Yep on new synchronizes. 1st and reverse were a bit slow to engage with the new synchros, started going to 4th, then 1st/reverse. However with a couple hundred miles on the clock it's shifting much better.

Standard did a freshen up on the transmission about a 100,000 miles ago. Really expect the same or better service this go. However since I'm only driving about 5,000 miles a year now and I'm almost 66.....yeah when I'm about 86 we'll see the next 100k and I'll post an update. That is assuming all goes well.

 

[SAndreasen]

I hope it works well . I'd like to find a reliable place that builds these