NV4500 Clunk when letting clutch out

[badger1]

Looking for your input please.

I have a 1997 2wd 2500 with NV4500. I recently bought a brand new NV4500 with clutch kit (stock) and a local shop put it in. Motor is stock.

They installed it and I am getting a "clunk" sound when I let the clutch out. It sounds literally like the clutch is clunking/slapping onto the flywheel. This was never there before with my old transmission and I have driven quite a few of these trucks and never heard this before. Also, when I am idling and in neutral and let the clutch out, everything gets noticeably louder. Any idea what this could be?

I brought the truck back to the shop and told them/showed them what it was and he gave me the standard, its new and has to break in and that there is a 12mo/12k mile warranty on the clutch and a 3yr/100k mile warranty on the transmission. So to put more miles on it and see if it breaks in or the sound goes away.

I should also add that at some times it is very difficult to get the shifter into gear. Its tough get into 1st and 2nd, sometimes 3rd and it sometimes grinds a little when it finally goes in. This doesn't feel normal either.

Any ideas what this could be? I read some threads and did some searching and some had similar issues with bearings being bad, when I asked the shop about it being a bearing, they said that there was a new one in the clutch kit installed.

I could really use some help/advice here. The shop might not be familiar with diesels, they don't work not them much, but clutch installation is pretty standard Id imagine and they have been in business for 20+ years. I don't like the feeling of knowing something is wrong but them telling youth wait or that its normal.

This was an expensive fix, the total was $3700 for new NV4500, clutch kit, install, materials etc. Im not going to accept "close enough".

Thanks for the input

 

[GAmes]

I doubt you bought a "brand new" NV4500. New Venture went out of business more than a decade ago. It sounds like you received a poorly built reman. Ask the shop what they used for oil. Castrol Syntorq is the lube called for. Some others will work but some will destroy the synchros.

 

[badger1]

I did double check before and after the install to make sure they used the correct lube, they assured me that they did, however they didn't specifically say Castrol Syntorq. Yes you are correct, the NV4500 is a remain, and as I said it comes with a 3yr/100k mile warranty. I found a couple other possibilities in my search, let me know what you think.....
"A bearing noise that occurs when releasing the clutch pedal to engage the clutch while in neutral, but goes away when the pedal is depressed is caused by a bad transmission input shaft bearing." Could it be possible that the input shaft bearing, or pilot bearings are bad? Could the clutch hydraulic/master/slave is not holding pressure? At what point to I go back to the shop and demand they figure it out? Something is not right, it should drive like a new truck.

 

[badger1]

I'm in the Twin Cities, MN and had a local shop do the work. I guess I would have preferred to take the truck to a diesel shop but at the time it was an immediate need and I didn't have time to look/ask around. If anyone can recommend a good shop to take the truck to here that could give some advice etc I'd really appreciate it.

 

[GAmes]

Trying to diagnose noises via the interweb is nothing but speculation. Noise going away when you depress the clutch could be the release bearing too. Pilot bearings usually manifest failure by not allowing you to shift with the engine running. If you aren't satisfied go back to the shop and ask the guy in charge to drive it and explain to you why it is making noise. I've replaced my clutch and transmissions several times and never had a clunk or a noise when in neutral when the components were new. Once again, my gut feeling is the rebuild was poorly done, based on what you describe.

 

[badger1]

Thanks for the feedback, I won't get a chance to get back to the shop for a couple days due to my work schedule but when I do I'll ask to see what lube they used and the paperwork for the transmission. Could be like you said, just poorly rebuilt. The way I see it is the install should be pretty straight forward when you have a gosh transmission and clutch kit, thats not diesel specific. So as long as they used the right lube, they said that they did, the only other factor is the transmission, assuming they put the clutch kit in correctly. We'll see what they say, I wish I knew someone that knew more about transmissions that would just drive it and tell me what they thought, I might try and find a transmission shop someplace that would go for a quick ride and tell me what they think.

 

[Matt42]

I have a sinking feeling that they just poured in Castrol transmission oil of some kind. I've read that Castrol isn't making Syntorq any more. (Take that with a grain of salt.) Chevrolet used the same transmission behind their ghastly 6.4 diesel (I had one), and it may still be available thru a dealer.

 

[badger1]

I've considered that, I did specifically ask them if they knew about the specific fluid before the job, and confirmed after...with assurance that they did. But...who knows, I've considered draining whatever is in there and replacing with the correct fluid, you can buy it online via amazon and there are several of the synthetic GL-4 makers if you read the forums.

I've made an appointment for next Thursday 30th for them to take a look again. This made me mad actually...when I dropped it off they ordered the parts and fixed it, to get the parts in and get the work done it was about a week. Then of course, reasonably, I had to pay to get the truck back, they are paid, so I've upheld my end of the bargain, but the job is not completed to satisfactory standards, but now they take their merry time before scheduling a time to look at it. Imagine if I waited a week to pay them?

If I owned a business and a customer said the job was making serious noises and they were unsure if it was good to drive, I would tell them to bring it in immediately, and if that meant pushing back a couple jobs, or staying over some night to catch up thats what I'd do, thats customer service and IMO totally expected when you own your own shop.

I'll keep everyone posted on the results and their findings after I hear back from them next week. Again its a holiday, so I understand this week, but I would think "bring it in monday morning and we'll take a look is reasonable". I spent $3700 on this to get the reman NV4500, Clutch kit, trans mount, and labor...thats a significant amount to me and I expect a quality job.

My concern is, although the clutch has the 12mo/12000 warranty and the trans is 3 year 100k mile...I'm sure that covers parts, not labor. So if they didn't grease a bearing correctly, or use the correct fluid and the syncs are junk or something else. Then the cheap part is covered, but not the labor to take it out and redo it. I refuse to pay for them to do rework that wasn't done correctly the first time. I'm going them the benefit of the doubt to make things right, but if they don't I'm going to explore options for compensation. I really don't want it to get that far, but I'm not gonna roll over with a $3700 bill and terrible craftsmanship that leaves me without a truck, and a pile of expensive parts.

I also have seen several NV4500 remans that say specifically with a paper on the trans to use fluid XXX part # etc....so its pretty obvious if it doesn't have brass syncs and they need to use a specific type.

I'll also ask to see the paperwork as I said before, the brand of trans and where it came from, clutch and what fluid etc.

We'll see how this turns out. Does anyone know a reputable shop in the cities with diesel experience? The only one I know of is Jags way up in Zimmerman, thats a little too far for me. All I want is an honest shop that does good work. I just want it to be done right.

 

[badger1]

Quick update, I brought the truck back to the shop one morning when the truck was still pretty cold and would let the clutch out and the sound didnt change much. The shop owner checked/topped off the fluid in the transmission and said he thought it sounded normal. He said to drive it and let him know if there were more issues. I drove the truck for another week and after a 100mile drive and the truck warm I went right back to the shop. You could here the sound when I was in neutral and letting the clutch out much louder once the truck was warm. he agreed this time that something didnt sound right. He said he would call the transmission shop, called and got a replacement "new" transmission coming, another rebuild. Dropped the truck off and he put it in...Im picking it up tomorrow and he said on the phone that it still makes noise when you let the clutch out in neutral and that maybe that is just how they are.

I'll let you know. I've had 5, 2nd gen dodge trucks with NV4500's and none of them have ever made any noise letting the clutch out, and none have ever been as hard to shift. I'm not a complainer either its just frustrating. We'll see how bad this one is. He said that its a brand new reman transmission, new clutch, pressure plate, machined flywheel, all new bearings...he said there is nothing that could explain it. If there is still noise/grinding I'm going to take it to another transmission shop in the cities I think and see what they have to say, get a second opinion.

Can anyone recommend a good transmission shop in the metro? I just want them to listen to it or drive it and tell me what they think.

Thanks for the feedback.

 

[badger1]

I also wanted to add, they were aware of the specific fluid requirements and put the fluid in that is sent WITH the transmission, so I'm assumign they reman them without brass synchros, otherwise it wouldnt be important enough to send fluid with the transmission from the rebuilder.

 

[GCroyle]

Yes, could be a transmission created noise or possibly a noise created in the transmission by a clutch disc torsion damper that may not be "stock". The torsion damper of a disc acts as a noise filter so if the trans is decent a heavy duty (for example) disc may have a very strong torsion damper, takes extra torque but may not be as effective at filtering out the pulsations of the engine that result from rapid RPM spikes from the engine. Especially at idle in N.

 

[badger1]

Wow, thanks I hadn't thought of that..it actually might make sense..that would explain the growl, clunk vibration when I let the clutch out in neutral, it almost does sound like a spring vibrating or something...also they said that they did put a heavy duty clutch in, not a valair or south bend...but it was one step up above stock, so maybe that has the heavier duty torsion springs...

Also could this account for the "clap" sound I hear sometimes when I let the clutch out in normal driving? It sounds like the clutch disc is clapping when it engages.

I'm picking it up in the morning, we'll see how bad it is. I just want it to be done right, I plan on keeping the motor/trans through thick and thin, even if I swap it to a different truck, I am meticulous with my engine maintenance and I want to make sure the transmission is top notch also, that and the fact that replacing everything with this last issue just about broke me, I can't afford to have more repairs like that down the road...

 

[badger1]

oh, the other thing I was going to mention for clarity is that when I am sitting in neutral and let the clutch out, the noise starts...and continues, this isn't a momentary sound while the torsion damper absorbs some torque...this sound starts and continues and won't stop until you push the clutch back in...that instantly quiets the noise and it disappears..While it is going its like a loud combination of vibration and grinding...

Like I said, I have had muscle cars with non stock clutch discs, multiple 1st and 2nd gen cummins with both the getrag and nv4500 (although those were all stock discs) and I've never heard anything like this before.

 

[NIsaacs]

Yes, could be a transmission created noise or possibly a noise created in the transmission by a clutch disc torsion damper that may not be "stock". The torsion damper of a disc acts as a noise filter so if the trans is decent a heavy duty (for example) disc may have a very strong torsion damper, takes extra torque but may not be as effective at filtering out the pulsations of the engine that result from rapid RPM spikes from the engine. Especially at idle in N.

The above quote is good info and is probably what you hear. When the transmission is cold you won't notice the noise much but when it warms up you will (oil thins out).

Do you have a stock 12.25 clutch or a stock 13"?

For reference here is a picture of a stock 13"

Now here is a picture of a heavy duty 13", note the "soft" hub springs in the stock clutch v/s the stiff springs in the HD.

If you have the HD clutch the noise is normal.

Nick

 

[GCroyle]

Nick's pic's are representative of a stock NV5600 disc and the very common style HD 8 spring old school tough as nails truck disc. Strong as all get out but lacks table manners. The 8 spring HD version doesn't have the pre damper or idle stage damper that id designed and sized to specifically address idle gear noise.

The torsion damper section of a disc is really challenged with a lot. Between handling the full engine torque, partial torque and that idling engine and doing its best to make sure you don't even know its in the system keeping the trans quiet and then take it for the life of the clutch. They get a workout.

Take Nick's top pic, clamp it on a FIXED object, put an 1 3/8" shaft in it, now with a really long breaker bar rotate it (the splined shaft) in the drive direction and watch the springs get compressed, keep going until you hit maybe 700 lb-ft then rotates in coast to about 500 lb-ft or so.

Our torsion damper tester at work does that in drive and coast then gives you a graph of degrees vs torque. Yup.

 

[badger1]

I really appreciate you guys explaining this, I guess I never even thought of it. I don't know what size clutch they put in specifically, I didn't ask, they just said the HD clutch kit, the full kit with all new bearings etc. But this starts to make sense with your explanations.

The only other issues that Ive had is the difficulty getting the trans into 3rd gear. It grinds ever.single.time. I go from 2nd to 3rd...however if it grinds a touch and I pull it back out and reattempt to go back into 3rd...its silky smooth. So I don't know if that is a synchro issue, or if its just a new trans that needs some break in...I don't know.

The shop said that when they first got the trans installed it was almost impossible to shift and get into gear but after working it a while it was functional...is that just because everything is new and tight? I had put about 1500 miles on the other trans and it was still doing it. We'll see if this new one that I pick up today shifts any better/smoother...the shop said that "the noise (vibration/rattle) is still there when you let the clutch out but its not as bad as before"....but now with you guys offering this other explanation obviously of course it would still be there because perhaps the trans isn't a problem, those torsion dampers will make the rattle and noise no matter what trans they are on, when under load. If thats the sound/noise culprit...I suspect it is.

So if I hear the noise/rattle I won't be concerned, I do hope that the trans shifts smoother though, the 2nd to 3rd was so bad it's caused me to miss a shift before, sometimes in situations where you don't want to miss a shift and slow down...it was almost a little dangerous...so I'd like to be able to move through the gears smoothly.

Thanks again for everyones feedback, I really appreciate it.

 

[GCroyle]

I don't know what size clutch they put in specifically, I didn't ask, they just said the HD clutch kit........The only other issues that Ive had is the difficulty getting the trans into 3rd gear. It grinds ever.single.time.

The size of the system is not the issue, the design of the damper is a question.

A clutch has no feedback from the trans , no clue what gear YOU are selecting. It only knows that it being asked to rotate the input shaft (pedal up) or do not rotate the input shaft (pedal down).

Question, engine running, trans in N, push clutch pedal down, 2 sec count select 1st gear. No issues? Now slowly raise the clutch pedal off of the floorboard. How far does the pedal come UP before you feel the initial clutch engagement and the truck stats to pull. Repeat evaluation several times until you are comfortable with your answer, in inches or fractions of an inch.

Gary

 

[badger1]

Gary, I'll do the experiment tomorrow and post back to you.





I wanted to report, picked up the truck today and put about 400 miles on it as I had to pick up a CL item for a friend.



Initial feelings:

The "new" transmission is great, finally right, silky smooth moving from any gear and back again...absolutely no grinding at all at any time. When I picked the truck up they told me this, and that the other transmission was super stiff from the start, they said this one felt normal from the get-go...so they said "there was def something wrong with the last one". I'm just glad this one feels so much smoother and absolutely no grinding going into gears. Finally! I can't believe I put 2000 miles on the last one.





Sound letting clutch out while in neutral: well as we suspected, the sound is still there, albeit MUCH quieter than with the last transmission, not anywhere close. I would described it as noticeable, but not obnoxious and not alarming. The last trans literally (and Im not exaggerating) sounded like a damn tractor when you let the clutch out in neutral.




NEW ISSUE:When starting out in first, accelerating and then shifting into second and accelerating..there is a winning sound...again like a gear drive...it has a gear sound...I don't hear this at all in 3-5 gears. This sound was not there at all in the last transmission, or in any NV4500 I have had before....So this is a new issue. I'll continue to monitor and see if it goes away, or if I can pinpoint any more specific instances or examples but thus far, thats the only issue. It definitely doesn't sound right. Makes me want to check the fluid but after the last incident and then having them add more etc, I highly doubt they would have let it leave the shop without fluid. I'm gonna drive the truck more tomorrow, do the experiment for Gary and see if I can get a better handle on what might be causing it.



On a positive note, I of course wasn't charged anything for warranty work. Its a hassle to have to bring it back in and deal with it, but I just want/need it done right, and they honored the warranty and have done their best to make it right. I can't complain about that and if its the trans rebuilder shady work thats not on them in my book. I know this should be a given, but I guess Ive had so many instances of warranty meaning nothing or trying to weasel their way out of accountability (thats with anything, appliances, plumbing etc) that when you find someone who doesn't give you any grief and just says, yup thats not right we'll take care of it...it very refreshing. So like I said, this has been a bummer thus far, and feels like its not quite there yet due to the whining sound in 1st and 2nd, but they've been very decent with me as a customer and I guess thats all a guy can ask for.

 

[badger1]

Gary,

I drove the truck for quite a while today, in town with several starts/stops. Honestly I think the easiest way to answer your question is, rather than describing how far from the floor before the clutch engages, its easier to explain the opposite....how far from fully out with your foot off, before the clutch engages and you're moving.

I don't notice any issues when doing your 2 sec count experiment and then putting the truck into 1st...I would say that there is only 2 inches or so from foot totally off the pedal when the truck starts to move...I hope that is a clear explanation. The pedal is the majority of the way out before the truck starts to move. It feels normal and smooth and Im used to it.

I'd like to hear what you are thinking.

Thanks and wishing you and all on the board a Happy Holidays!

 

[GCroyle]

The clutch industry calls it reserve travel. The distance the clutch pedal comes UP from the floorboard before initial clutch engagement. I'm sticking with the description that my industry uses. It helps determine if the release system and clutch function correctly to provide clutch release.