Element

iTrader: (5)

Haven't done a whole lot with transmissions, so I'm not too sure what could be causing the noises I'm getting. In neutral while idling, with the clutch out (not depressed), I get a sort of rattling/grinding noise, that instantly goes away as soon as the clutch pedal is depressed. First two things that come to mind - pilot bearing or throw-out bearing. However, both were replaced about 20,000 miles ago (roughly) when I get an OZ700 put in the car. She's always been a little noisy at idle with the clutch out, but that was no more than a low-key sort of grumbling, whereas this is loud enough for me to hear with my music turned down and sitting in traffic. No problems shifting or anything like that, but I'd rather not have some sort of catastrophic failure before I know what's broken.

Jonathan@Tick

iTrader: (5)

You've probably got one or more bearings in the transmission going bad. When the pedal is depressed the transmission stops turning. Thats when your noise goes away.

The pilot bearing would make noise only when the pedal was depressed. Any other time the input shaft would be turning with the crank, there would be no movement in the pilot bearing.

The throw out bearing would probably make noise at all times in an LS1 car. The reason being is the spring under the tob that constantly keeps it pressed to the fingers on the pressure plate. It would probably be louder or worse when the pedal was pressed however since there would be more load on it.

You may want to check the fluid level in the tranny. If its low, top it off and see if anything changes.

thesource

iTrader: (60)

I doubt it a bearing but its possible . If it is a bearing , its going to be the input shaft bearing or the main shaft pocket bearing .

Does your car have a large camshaft in it ? How does it idle ? What fluid is in the trans ?

Element

iTrader: (5)

Still has a stock cam. Idle is good, steady at about 750-800. No change in idle quality between the car in neutral with the clutch out, or the car in neutral/gear with the clutch depressed. As far as I know, the trans fluid is stock stuff (I had thought it was changed when I was the clutch swapped, but that turned out not to be the case).

I'm trying to figure out how to properly drain and refill (4 quarts of Dexron III, right?) the trans using only two jack stands behind work (the joys of living in an apartment).

thesource

iTrader: (60)

Its probably the throw out bearing . Do you hear the noise while driving down the road ? If so , what gears do you hear it in ?

Element

iTrader: (5)

After taking the car for a spin for a half hour with the radio off and cruising at low rpms, it almost seems like really, really, really loud gear mesh noise from the trans. The noise is there in gear while driving, too, and it makes a loud sort of of crunchy engagement noise when I start from a dead stop, and it gets noticeably louder and "crunchier" when coming out of a rolling stop (maybe 10-15mph) in 3rd gear, really getting the rpms low and loading the transmission.

Not too sure why it'd get louder all of the sudden, though. New trans fluid is on the list, but I might make it a priority now. Would a Synchromesh fluid work better than any normal Dexron 3, or should I just stick with the normal stuff?

thesource

iTrader: (60)

It could be something in the clutch . I have seen situations where a broken spring in the clutch disc does the same thing as you are describing .

Element

iTrader: (5)

Oh, goody. That'd be just what I need.

I'll switch the fluid and see if that helps, and go from there.

SS1875

iTrader: (34)

Keep us informed as I am having the same issue after the install of my Tex OZ700. My tranny was rebuilt 3years ago with all the Viper internals and it only has about 2,000 miles on it since...I hope it isn't the tranny.

calhoon

iTrader: (6)

This is simply a roll over noise. It comes when , at idle, the lash in the system excites the transmission gears. You hear this more now because you cahanged/ have an aftermarket clutch. The neutral or centering spring package of the clutch is developed to minimize this-- a job aftermarket clutch guys never do---hence the neutral noise you have.Also on &
off throttle steps can cause the gears to rattle /clunk if the clutch springs miss this tune.Using too thin of an oil can make this worse not to mention cut the trans life. Dex 111 spec ATF only. If you must go synthetic = Mobil 1 ATF only. Its more of a anoiance than a concern