Trans noise after rebuild (new clutch and bearings)

[stealth13777]

So, got a noise in neutral when off the clutch. It started as just a 'whir' noise I thought might be normal, now I would describe it as a metallic clunk/ whir. Here's a video if anyone can help me out. Posted this in my rebuild thread but decided it deserved its own thread. Thanks.

https://vimeo.com/124163304
I'll leave this video (david85 indicated he could hear my issue), but all I can hear is normal diesel noise. There's a definite metallic sound from the clutch area when standing next to the truck though. If you need more info or video to help out I'm happy to provide it.



Previous response from david85
Hmm.....I can hear it alright. My guess would be in the throw-out bearing or damaged clutch spring. Have you dropped the bell housing access cover yet? Might give some clues if something is rattling around in there. Only time I heard something quite like this was on a powerstroke that had a bad dual mass flywheel. Not the same transmission, but it sounded similar.

Has the truck developed any tendency to creep when in gear and the clutch pressed? Any louder rattle when it shuts off? Any difficulty getting the transmission into gear from neutral when running?


Me answering those questions:
Have not had the cover off yet but I will look in there when I have time. I recently drained and filled the transmission with gear oil and now of course I have noticed some oil (which smells like gear oil) on the trans. I am hoping it is just coming out of the PTO cover seals, but this problem is looking more and more like the trans is coming out anyway. Plus the leak is a separate issue anyway.

It does not creep in gear that I have noticed, no louder rattle when shutting it off (in fact, I noticed it was quiet for the first 5-10sec after startup), and there is no noise with the clutch depressed, at least that I have noticed. I HAVE had trouble getting the trans in gear from neutral, most often (almost every time) going into reverse but a couple times going into first. I let off the clutch briefly in neutral, push the clutch back in, and then it goes into gear.

I would like to diagnose this down as much as possible so I can buy parts and fix it; trying to get this truck reliable enough to daily drive for a week or two while I work on my car. I will do diagnostics as recommended. I would also like to know how bad of an issue this is.. ie., 'do not drive it', or 'it could break on you within 50-1000 miles', or 'it wont hurt anything for awhile but will need to be addressed'. Will it leave me on the side of the 2 mile bridge I drive to work where I believe 5 people have already died this year (not where you want to break down)?


More background if needed:
It is a factory T19 with a brand new Luk clutch (and associated bearings that came in the kit, including the throwout bearing) on a single mass flywheel (I believe that's what the truck came with, and it is what was on it when I bought it.) Flywheel was turned when the clutch was installed about 100 miles before I pulled the engine to rebuild. It is possible I guess that I damaged the clutch during engine install, or that a bearing got angry sitting for 8 months in a moist environment. I coated the throwout bearing with wheel grease after the engine rebuild because I had noticed the 'whir' in neutral clutch out prior to pulling the engine. Still think that noise might just be normal, not sure. The throwout bearing was bad when I bought it, so I put this clutch in, then rebuild... never heard it any other way. The engine was tough to get lined up so we wrestled with it and tossed it around some. I recall my friend saying "I hope we didnt mess up the ____, but even if we did, just pull up to a tree if it makes noise and give it some gas and it should straighten out". It seems to me this noise has developed though, not been there from the start. Been about 250miles since the rebuild, so maybe 350 total on the clutch.

 

[LCAM-01XA]

Does the noise go away when you raise the engine speed? Our first 4-speed was a T19 and it scared the heck outta me upon its first start, it was making noises I'd expect to hear from a ZF, not a T19. It turned out it was the TOB fork vibrating, if we so much as twisted it slightly the noise would instantly go away. Of course one cannot hold the thing twisted and drive at the same time, so the solution was to bump the idle speed up from 700 RPMs to about 800 RPMs or so apparently this was enough for the fork to get out of its harmonics area and stay quiet. That transmission has since been replaced twice (not cause there was anything wrong with it, just needed different gear ratios) but we never bothered to turn the idle back down to check if the vibration will start again though.

You're having issues with reverse gear because it is not synchronized, she will slide right in nice and easy only when the gears are aligned well, which really doesn't happen with the countershaft still turning right after you clutch in. With a T19 putting the truck in any forward gear with the clutch pushed in stops the countershaft and thus more or less aligns the reverse gears. Our 2nd 4-speed was a NP435, that thing has a non-synchronized 1st gear in addition to the reverse - the standard procedure was shift into 2nd to stop the countershaft, then shift into reverse to align the gears well, then she would go into 1st no problem. On a good day she would go in 1st right out of 2nd, but it was a rare occasion. Shifting straight into 1st after being clutched out at a long red light or something, forget it, not happening - well not unless one lets her grind till she's ready to shift.

Your 1st gear being somewhat temperamental also, this suggest that its synchro is wearing out. Not something I'd consider a big deal. Will she leave on hanging off the bridge, that's a tough one - being a 4-speed the answeris most likely no, but just in case pull one of the PTO covers and see what the fluid and the gears and such look like inside. If oil comes out with no metal shavings, and the gears show no irregular wear markings, then I'd think you are good in that department.

 

[stealth13777]

Does the noise go away when you raise the engine speed? Our first 4-speed was a T19 and it scared the heck outta me upon its first start, it was making noises I'd expect to hear from a ZF, not a T19. It turned out it was the TOB fork vibrating, if we so much as twisted it slightly the noise would instantly go away. Of course one cannot hold the thing twisted and drive at the same time, so the solution was to bump the idle speed up from 700 RPMs to about 800 RPMs or so apparently this was enough for the fork to get out of its harmonics area and stay quiet. That transmission has since been replaced twice (not cause there was anything wrong with it, just needed different gear ratios) but we never bothered to turn the idle back down to check if the vibration will start again though.

You're having issues with reverse gear because it is not synchronized, she will slide right in nice and easy only when the gears are aligned well, which really doesn't happen with the countershaft still turning right after you clutch in. With a T19 putting the truck in any forward gear with the clutch pushed in stops the countershaft and thus more or less aligns the reverse gears. Our 2nd 4-speed was a NP435, that thing has a non-synchronized 1st gear in addition to the reverse - the standard procedure was shift into 2nd to stop the countershaft, then shift into reverse to align the gears well, then she would go into 1st no problem. On a good day she would go in 1st right out of 2nd, but it was a rare occasion. Shifting straight into 1st after being clutched out at a long red light or something, forget it, not happening - well not unless one lets her grind till she's ready to shift.

Your 1st gear being somewhat temperamental also, this suggest that its synchro is wearing out. Not something I'd consider a big deal. Will she leave on hanging off the bridge, that's a tough one - being a 4-speed the answeris most likely no, but just in case pull one of the PTO covers and see what the fluid and the gears and such look like inside. If oil comes out with no metal shavings, and the gears show no irregular wear markings, then I'd think you are good in that department.

I will go outside tomorrow and try raising engine speed with it in neutral like that. Hadn't thought of that. Only time I have done that was when I was timing it and my head was in the engine bay so.. Wasn't gonna hear much else haha.

Just changed the oil, it actually looked really good. I'll get a look inside for sure sometime soon when I track down the leak. Go figure it showed up right after a fluid change. I will also crawl under it idling and see if poking around the fork (nothing that's turning) stops the noise. Boy would that be a nice simple solution.

That first gear certainly has some wear on it but I'm also rusty with a manual and have probably been trying to push it into first with too much speed still on the truck; can't recall having an issue from a stop just 'notchy' like I imagine truck trans just are (most of my manual experience is from cars).

A simple solution would be nice, versus needing another clutch or throw out bearing and having to drop the tranny. Good starting point diagnostic wise, thanks!

If I don't find the noise with what's above, I may have enough time to pull the cover tomorrow and take a look as well. Wish I could get my auto stethoscope in there, but not with it running I don't think.




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[stealth13777]

Alright. Got out there today and all I got was the whir (which I think might just be normal). But here's a video. This is the original noise.
https://vimeo.com/124331069


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[LCAM-01XA]

On ours one could just grab the form by the slave cylinder end and give it a light twist and the noise would go away. Certainly did not feel brave enough to poke into the bellhousing with the engine running.

First gear is 4:1 on these trucks, not very low but you still gotta be going pretty slow to be able to shift into it with just the synchro. Of course you could also try double-clutching it, but that's also somewhat of a hit-or-miss deal. And yeah, she will shift a bit slow, it's just a truck thing - if you extend your shifter till it almost touches the steering wheel it will pretty much automatically slow your shifting down just due to how long it gets and how much you gotta move your arm Should still slide from gear to gear pretty smooth tho, the T19 is IMHO one of the nicest-shifting heavy-duty 4-speeds out there.

Video didn't work for me, but no matter, only whir is good, however next time she starts making the funny sound just bring the engine speed up 100-200 RPMs and see what happens.

 

[david85]

I didn't realize you had a new clutch installed (so that probably rules out the TOB and related clutch parts). The throw out arm seems plausible to me though. It could also just be some bracket or other metalic part near the engine or transmission that's causing the noise.

 

[stealth13777]

I didn't realize you had a new clutch installed (so that probably rules out the TOB and related clutch parts). The throw out arm seems plausible to me though. It could also just be some bracket or other metalic part near the engine or transmission that's causing the noise.

I sure hope the new parts are good. And stay that way awhile!


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[stealth13777]

I know, my diagnostics are slow. Lot going on and this is not yet a priority. No noise when cold. However, once warm the noise reappears. I find that interesting. Will look into the suggestions provided when I have time


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[south bend clutch]

What brand clutch did you buy?

Peter

 

[stealth13777]

What brand clutch did you buy?

Peter

It was the Luk kit Rockauto sells. As I bought it before my rebuild, the 1yr warranty has come and gone. Came with everything, including throw out (only thing bad before was the throw out bearing), although I can't speak to quality. I actually paid to have that installed (and then subsequently took most of it apart for the rebuild).

I don't remember this noise from before, so it seems likely something happened during the rebuild.

I see you're from south bend clutch. Familiar with my symptoms and know a solution? Cause if you do maybe I can buy said solution from yall this time...

Otherwise I will find time to diagnose further, eventually


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[south bend clutch]

Some designed discs can create a gear roll over sound but the Luk usually does not. You could have a pilot bearing failing or failed which you would want to address ASAP. You may also want to do a diagnostic check to make sure your injectors are firing properly.

Peter

 

[stealth13777]

I have another video I will throw up here later, but so far my diagnosis indicates an actual problem, not just a vibration

I have not dropped the cover yet, but have played around a lot hoping to find a source of vibration and be done with it. Plenty of stuff vibrates on these trucks haha, but none seem to make this noise.

The strangest thing is how the noise manifests itself. There is zero, zilch, nada, no noise at all when the truck is cold. I did not notice it warming up either. However, after a 5min drive the noise becomes noticable. After about 10min, it's bad enough so I don't let off the clutch at all when stopped. I just cannot quite compute what would warm up down there and change enough to create this problem. I do think this is the key to determining the issue though.

I read an old thread on dieselstop (that agnem posted in) where they found the throwout to be the problem (with new Luk kits as well), despite the fact that it should make noise when depressed, not when off the clutch; I guess it may not fully disengage from the clutch? It was also mentioned by Agnem that the pivot and fork should be replaced. I definitely didn't do that. Being that I am wary of getting up in there with the truck running, and that I am a 'diagnose and fix once' type of person (who has the time?) I am still looking for anything that could point me toward the problem. Somewhere in the evidence I have is the answer, I just can't find it with my limited knowledge.

Found this from Luk:
NOISE
Growling or grinding when the clutch is engaged.
SOURCE
Transmission input shaft bearing


NOISE
Squealing when the pedal is actuated and held.
SOURCE
Pilot bearing or pilot bushing


NOISE
Chirping that intensifies when the pedal is slowly actuated.
SOURCE
Release bearing


NOISE
Chirping while idling in neutral that disappears when the pedal is slowly actuated.
SOURCE
Fork/pivot ball contact point

I have the first and last issues there. So still not a definite source. This weekend I will get under it (with a helper to make me feel safer) and really pull on the fork to either eliminate that possibility or finish the diagnosis. It was recommended before but I didn't really mess with it a whole lot.

If it makes any difference, the trans is full of fluid and what I put is was WalMart 80W90 GL5 Gear Oil. I don't recall anything but the whirring before the change (and the whirring may be normal for this trans, I have no frame of reference.), but I also had driven the truck very little.

Toward the end of the video the noise is very noticable. The warm/cold difference still has be baffled. There has to be. Good reason for the difference.
https://vimeo.com/125864826

 

[LCAM-01XA]

80W90 is what we ran in our T19 as well, and many others do so also, doubt that's your issue. If it's temperature-related, it's gotta be pretty marginal to begin with as those transmissions usually run at less that 150F so you're looking at 70F-80F difference from cold to normal operating conditions...

Out of curiosity, did you do something with the input bearing retainer? The same part the throw-out bearing also rides on, adjusting the stack of gaskets under it is how you adjust the bearing's preload IIRC - maybe something went amiss there during the rebuild?

 

[stealth13777]

80W90 is what we ran in our T19 as well, and many others do so also, doubt that's your issue. If it's temperature-related, it's gotta be pretty marginal to begin with as those transmissions usually run at less that 150F so you're looking at 70F-80F difference from cold to normal operating conditions...

Out of curiosity, did you do something with the input bearing retainer? The same part the throw-out bearing also rides on, adjusting the stack of gaskets under it is how you adjust the bearing's preload IIRC - maybe something went amiss there during the rebuild?

Not intentionally, but I did a lot of crawling around in that engine bay cleaning and working on stuff. Easily could have messed with something. You may be on to something.

Other than to grease the throwout, I didn't touch any of that stuff intentionally except what I had to in order to pull the engine; I've never worked on manual trans before. Had the fork zip tied to hold it in place before I pulled the engine. Gonna have to learn quick


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[LCAM-01XA]

You wouldn't be able to mess with those gaskets unless you intentionally unbolted the tube the input shaft slides thru when it disappears inside the trans. The TOB rides on the outside of that tube, and tube itself has flange on the transmission end where it bolts to the trans with 4 bolts. There is zero need to mess with that part, and no one ever does, unless they're rebuilding the trans, then it has to come off. So if you never rebuilt the trans itself, just slid the new clutch parts in/on, then chances are it's still how it left the factory. Which of course doesn't mean your input bearing is not on its way out, that could very well still be the case - any idea how many miles on that transmission, and how hard/heavy?