[STiShawn]

OK, went to the Fort Scott Rally Cross this last weekend. ON the way home I noticed an odd clicking from the car. Stopped and jacked the car up before we ate dinner, checked the rear diff (thanks to Shawn Walker)...

the car drives, shifts and runs fine
the diffs all work
the sound is best described as playing cards in bicycle spokes but more solid
it seems to originate under the shifter/radio area
it is RPM dependant
only happens on coast down when no engine load is present
it gets louder when the clutch is let out, but remains when it is in
it is in all gears, but not when the car is stationary, it MUST be moving for the sound to occur
I can "feel" the sound in the shifter

Car is a 99RS, 5 spd
Im gonna power wash the chassis tonight and check all the driveshafts for play

Theories include:
Dying center or front diff
dying throw out bearing in clutch
broken U joint
wheel bearing
tranny bearing
something stuck on the driveshaft
starter hitting fly wheel
cv joints
tire pressure
something rubbing the driveshaft the wrong way


HELP!!!!

 

[Keith99RS]

Sounds like the drive shaft may have something wrapped around it whipping the underside of the car near the consol area. I'd definitely give it a good power washing too. It seems like most mystery noises that happen after hard driving on snow or mud are related to frozen snow or dried mud throwing something out of balance, and a good wash seems to help eliminate these problems.

 

[STiShawn]

Im gonna blast the hell out of 'er tonight and see what falls off...lol
The consensus seems to be clutch related down here...Im still open to all ideas. Another thing for me to check are motor and tranny mounts......
Thanks Keith..anyone else?

 

[STiShawn]

nothing fell off after power washing, and another suggestion of CV Joints has entered the fray.....
Please help me out here, I dont want to have to go to the dealer for this.....

 

[RS25.com]

CV joints tend to only make noise when you are turning, not going straight. Sounds like you said it makes this noise when you are (1) in gear and (2) coasting down. So it does NOT happen if you are (1) in nuetral but (2) coasting, right?

To me that says one thing - something between the clutch and the driveshaft - hence the transmission/transfer case. Now, what could go wrong in the tranny after an Auto cross? Well, you still could have something stuck in there, irregardless of power washing it, like a large stick jammed up top of the transmission hump. If you have not already, you should get the car up on ramps and crawl under. Look for signs of something rubbing a moving part like the driveshaft(s).

Another fun thing to do (but scary stupid, too) is to put the car up on four jackstands so no wheels are on the ground, put someone behind the drivers seat, and have them put it in gear and slowly rev it enough to observe the problem. Doing your best to realize that the car will probably fall off the stands and drive away, running you over in the process, try to look under the car and listen for the noise. This is VERY dangerous, and has the potential to drive the jackstands through the bottom of your car, or cause an accident, so I've only done it once. When I was young and foolish. Obviously, don't stand in front of or crawl under the car if the wheels are moving!

Although I doubt it, the other thing could be the starter - if you hit something big enough to whack it out of position, it may be hitting the flywheel. But that does not jive with your symptoms.

 

[Dave G]

Have you checked your tire pressures? one low front tire (possibly rear) could cause a differential to unload to the one side (or front to rear)...hence only makes the sound while in motion and coasting!:sunny:

 

[STiShawn]

it does make the noise in neutral, sorry, aasnt clear on that one. but it is much quieter than it is when in gear. No more or less noise when cornering and coasting though.
Im getting under the car this weekend and will look for any and everything that could be outta whack...
Im not starting the car on jack stands though, Im pretty crazy, and some would say stupid, but i dont have a death wish....

Any other ideas?

 

[STiShawn]

isnt the starter on the top of our bell housing though? I'd have to hit something really big...good idea though, might have knocked it loose on a bolt...I will check that too.

Thanks gang!

 

[STiShawn]

How do I check my throw out bearing with out dropping the tranny?

 

[Dave G]

Throw out bearings growl and/or squeal...I've never heard one 'click' before. Does the volume level of the sound increase or decrease with applied load or speed?:sunny:

 

[Dave G]

If you can get your hands on a stethoscope (and about two feet of additional tubing to extend the reach of the sound cup), tape the sound cup to the clutch arm while listening and have someone engage and dis-engage the clutch. A throw out bearing should make noticably different sound when 'in' verses 'out'. If there is no change in the sound it's probably not the throw out bearing. What condition is your clutch in? Have you seen evidence of clutch lining in the engine compartment? If you have you may want to pull your starter and clean it out! Clutch lining will get into the solenoid path and hold the solenoid partially out which could allow the flywheel to periodically hit the starter drive gear (which would be bad for both starter and flywheel!) My 88 XT had this problem once after a severe clutch failure. The starters look very similar...could be the same thing.:sunny:

 

[STiShawn]

Thanks Dave, my clutch has 11k miles on it, brand new ACT when my motor was replaced.
Pardon my naive'te but what does clutch lining look like?

 

[STiShawn]

the sound goes away when throttle is applied, and decreases in frequency as the car coasts down to a stop...its rpm dependant.

When coasting if I clutch in, the sound volume drops, if I clutch out in gear the sound level goes back up.

 

[Dave G]

Clutch lining in your engine compartment or bell housing is a fine powdery material usually brown, the color of the clutch plate when new (unless you've smoked your clutch then it can be black or grey) Carbon or carbon/kevlar would be grey to black and copper would be copper color. When you work your clutch hard the lining 'sheds' and is thrown off into the bell housing and engine compartment. The material in the bell housing also ends up in the starter and can build up to produce the effect I mentioned earlier. Does the frequency change in each gear (at a given RPM ie 3000) or does it change with (road) speed? A throw out bearing make the most noise when the clutch is in and gets quieter when let out. Noise volume in your case is during decelleration ....this leads me to think that a thrust bearing is involved or the center differential is transferring torque unevenly. What happened to the original engine and clutch? :sunny:

 

[STiShawn]

how can I check the center diff and or the thrust bearings? is there a way or do I have to go before the mercy of a dealership?

 

[Dave G]

Does it make the same sound in reverse?:sunny:

 

[STiShawn]

no sound in reverse at all....just forward.

 

[Dave G]

Looks like a trip to the dealer dude! With no sound in reverse that kind of narrows it down to the trannie main shaft and it could be a thrust bearing. I have to admit this is a new symptom, one I am not familiar with.:sunny:

 

[Dave G]

It's remotly possible that you may have sheared a trannie mount too. That could also explain why you hear the sound the loudest while decellerating. But that also means 'something' on your driveline is banging into the underbody somewhere. In reverse the suspension loads up differently (now you have clearance!) and it doesn't make contact. Either way it's going to have to up on a lift with no tire contact so it can be run and inspected while in motion. good luck!:sunny:

 

[STiShawn]

d'oh!