Michael---Your suspicions are correct, in that the squeal you hear is
coming from the throwout bearing, as it makes and loses contact with the
(spinning) clutch. There are reasons for this sound to show up only when
there is a partial load on the bearing. The bearing itself probably is
not (yet) going bad, but sounding off from the probability of it
spinning in a different circle than the clutch. When the clutch is
disengaged, the friction between it and the bearing is great enough to
avoid slippage, hence no sound.
So far as to why this has showed up "after a recent transission service"
I will offer a few possibilties:
a) The tranny was bolted to the engine backplate without the proper
alignment. (The dowels or 3/8" bolts were left out) This can set up the
noise you hear.
b) The front cover that the t/o bearing carrier slides on may be worn to
a point that misalignment is taking place at the tob / clutch junction.
c) Some bearings are just not up to the task, even after only the few
miles you have. If this is the case, the squeal will get progressively
louder and will continue protesting deeper into clutch pedal depression.
Michael, I would ask the shop who did the work if they reinstalled the
alignment bolts when put the tranny back in. If they give you a blank
stare, there's your answer.
It could be possible to align the tranny again without taking it
completely out, by loosening all of the bolts and tapping in some
dowels. (These 3/8 inch holes are located at approx. eight and two
o'clock, looking from the back, forward.)
There should be no real harm to drive the car as-is. As the squeal gets
worse, you'll know when it's time to fix it!
Dick
From:
mgc4@CDC.GOV(Campsmith, Michael (CDC/CCID/NCHHSTP))
Fellow listers--
The transmission on my 1974 TR6 was recently serviced and now I have a
noise that wasn't there before.
There is no noise with the clutch either fully disengaged or fully
engaged. However, the noise--a "squeaking" sound--comes on when I first
depress the clutch pedal, goes away once the clutch pedal is depressed
completely, returns when the clutch is almost fully let out, and is gone
once the clutch is again fully engaged.
The symptoms above make me think it is the throw out bearing. My dilemma
comes about from not wanting to pay for another transmission removal and
replacement of what was a previously silent bearing. The entire clutch
mechanism and bearing were replaced less then 5k miles ago--the brand
name isn't coming to me but might be in my records.
Any other thoughts on possible sources of the noise, or better yet a
"magic" cure?
As always, your insight is greatly appreciated.
Michael Campsmith
1974 TR6 (now BRG)
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