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I have a 98 C5 6 speed with heads, cam, header, exhuast, etc.
Recently I tore down the motor and drivetrain for some work. Motor seems to be fine but upon installing the drivetrain I have been having issues. I have put it together for the third time this month and still seem to not be seeing much of an improvement. I installed a new Monster LT1-S twin disc clutch along with 18lb light weight flywheel, I also decided to install a stock C5Z transmission and diff along with DTE brace and pfat diff/trans mount. Torque Tube was also rebuilt with new bushings and all not to long ago where I also replaced the pilot bearing with a copper bushing. Originally after clutch install my problem seemed to be the car was extremely hard to get into gear, I tore the car down and noticed the new slave had bascially come apart and melted on the input shaft which I took as the slave possibly not being seated properly. I replaced the input shaft, a new slave, and a new Monster release bearing and torqued it to spec and assured it was fully seated, I also inspected the new clutch disc for wear which seemed fine and I retorqued it in the 3 phases as well. The car now shifts into gears really smooth while driving or at stand still, so im not having any trouble shifting, my problem now is the clutch is still in break in period maybe 50 miles at most
1) I have a really bad like screeching noise if im downshifting into a lower gear as I slowly release clutch, also when taking off in either first gear or in reverse and releasing the clutch it makes the same groan/screech until released. Also if im in gear and press in the clutch and slowly release it, it does it too. I have attached a video of this.
2)1) I have had a kind of wining noise after reaching 3rd gear in the higher rpm of the final gears and it seems to be dependent of throttle, no throttle the noise goes away, with throttle the noise follows and increases with more throttle, Not sure if this is related to my main issue but I just assumed maybe a worn acceleration bearing in the diff I got
Im completely lost to what this might be, not sure if its the clutch, if something with the drivetrain is out of alignment or maybe the new input shaft is rubbing on the slave cylinder again or what, but I dont feel like its normal to hear these noises during break in. I used the pilot tool to make sure everything was lined up, everything was also torqued to spec and measured for shim, when i replaced the first slave and input shaft all the rubber couplers on the torque tube still looked good. Any suggestions? Input?
Bad Pilot Bushing maybe? This is the only thing I haven't replaced, The monster came with a Pilot Bearing which i dont like so i kept my pilot bushing which only had maybe 8k miles on it at most. Or maybe the damaged slave cylinder, release bearing and input shaft damaged the break in process of the clutch?
Based on the video it is tough to tell where the noise seems to be coming from. Is it coming from the front of the car, rear of the car, right under you?
My first instinct is to say the pilot bushing is the culprit but I can't be sure.
Side note: Are you the same GradyBaby16 from CRSX?
Based on the video it is tough to tell where the noise seems to be coming from. Is it coming from the front of the car, rear of the car, right under you?
My first instinct is to say the pilot bushing is the culprit but I can't be sure.
Side note: Are you the same GradyBaby16 from CRSX?
I emailed Monster late last night and awaiting a reply from them. I feel as if they will just tell me the noise isn't normal and needs to be dissembled ha.
To me the noise seems to be coming from below me, more towards the front of the car, like within the bell housing area.
And yes I am also the same GradyBaby16 form CRSX ha
You could always have someone sit in the car, you crawl underneath and pull the clutch inspection cover and have them pump the clutch a few times just to see if there is anything visibly wrong with it.
I'm also a long time CRSXer. Went by the same name and spent all my time in the turbo section.
You could always have someone sit in the car, you crawl underneath and pull the clutch inspection cover and have them pump the clutch a few times just to see if there is anything visibly wrong with it.
I'm also a long time CRSXer. Went by the same name and spent all my time in the turbo section.
Yeah hoping to tear into again this weekend. I guess that would be a good idea also, Remove the exhaust real quick so i can drop the clutch inspection cover then reinstall the exhaust so it will be quiet enough to hear and still see. May just do that tonight after work and wait on a friend to come over for the weekend.
Nice, CRSX where good days, funny we both went from a DC5 to a C5 haha, I see you like your turbos though ha. Bought a turbo for the DC5 and never installed, planned on doing a LSA blower setup on this car but this drivetrain issue has stopped that.
Well, tore down the drivetrain after work last night... input shaft and slave cylinder all looks fine, I havnt torn down the clutch yet but I'm thinking fine... however I did try and look at the pilot bushing and it looks like its probably my problem, I think I see a crack at 3 o clock in the pictures... wont know for sure till friday when I lower the front subframe and pull the bellhousing, clutch and flywheel then the pilot bushing.
If it is the pilot bushing my problem now is deciding whether to replace it with another solid copper bushing or the OEM style needle bearing. My monster clutch came with a needle bearing but I opted not to use it since I had put in the copper bushing only a year ago, and have heard horror stories about the needle bearings failing and tearing up the input shaft... any opinions on copper solid bushing vs needle bearing?
I'd go with the bearing, I've been using the bearing since day one with no issues but you do have be a bit more precise when lining everything up. Did you use any lube on the input shaft? I always do dry graphite lube on the splines and the tiniest bit of grease on the tip of the shaft to help it slide into the bearing.
Yeah I never lubed the input shaft, always assumed you weren't supposed to. I guess I'll try some graphite lube on splines and some high temp lube on the end maybe. Got the pilot bushing out the other night and compared, it wasnt cracked but the pilot bushing fit really loose on the input shaft like it had been wollowed out alot, vs the bearing which fit much tighter, also there was all kind of ring marings inside the input shaft. Not sure what happened, maybe alignment. I think I have heard installing the torque tube itself is better for alignment but I've always installed the whole rear end, trans ans torque tube as a single piece. I cant imagine the hassle of doing tube only then ligning up the transmission and sliding the shift linkage in as well as bolting up the trans and trans brace all with such limited room in the tunnel.
I thought the bushing and bearing were two different sizes but now I can't find anything that backs that up. I do know for a fact that I have two different LS clutch alignment tools, one fit inside my pilot bearing and the other did not. I believe somewhere between 1997-2004 they changed the input shaft diameter enough that you can't swap between the bushing and bearing, the early years need the bearing and later years need to bushing. With all that said, I could be wrong.
Hmmm, wonder if that was my case, I have a 98 and i know most changes like that where made in 01 if at all. Got the car all put back together late last night, it was close to 2am though so I could only make a quick 5 minute drive. The big screech so far is gone, but the whine on acceleration is still there, im starting to think that may just be from the diff i picked up and the sound traveling up the torque tube. After work im going to put some miles on it and see if everything else other than the whine seems fine and whether the pilot bearing was my main issue or not. If so I may drain the diff fluid and go a little thicker and see if the noise changes at all. I do have spare diff internals from my old diff which was good before cracking but dont feel like dropping the rear end again. So well see
My '99 diff had a slight whine ever since I bought it no matter what fluid I used. After you drain and fill take a quick, short trip around the neighborhood and then lift it back up and top off the diff fluid a bit.
Last edited by Turpid porpoise; 07-19-2018 at 08:45 AM.
My '99 diff had a slight whine ever since I bought it no matter what fluid I used. After you drain and fill take a quick, short trip around the neighborhood and then lift it back up and top off the diff fluid a bit.
Yeah the Diff whine is more annoying than it really being a problem, I dont remember my old one whining then again its been 7 months since I drove this car ha, I dropped it off at the paint shop yesterday, so when I get it back next week, I may drain it and refill it with some thicker gear oil and limited slip additive again. If no fix ill probably just deal with it until winter when I may tear it down and swap in my old diff internals which are still good. Granted the interior above the shifter is currently gutted so when I reinstall the shift tunnel rubber, shifter boot and center console I may not even hear it.
YIKES!! PILOT BEARING was my INSTANT diagnosis the instant I heard the noise.
WHEW!! Lucky you didn't destroy the input shaft bearing surface.
NEVER NEVER NEVER NEVER use a solid bushing in an LS application. They never hold up. The standard GM Replacement needle bearing always works and works well.
YIKES!! PILOT BEARING was my INSTANT diagnosis the instant I heard the noise.
WHEW!! Lucky you didn't destroy the input shaft bearing surface.
NEVER NEVER NEVER NEVER use a solid bushing in an LS application. They never hold up. The standard GM Replacement needle bearing always works and works well.
Bill
Yeah that was my spare input shaft too so i would have been stuck if it got damaged, should have the car back from paint this weekend, but I believe everything is all fixed now, and lesson learned on the solid bushings, never again.
07-10-2018, 11:04 AM
C5 Corvette Clutch/Drivetrain noises
