915 sounds like small dental instrument

[wannaporsche]

Sheesh - I have a fairly well sorted SC, and the transmission shifts super smooth in all gears. I street parked it today, went into a class. When I got out of class and drove away, I noticed a very unusual singing sound when pulling the shifter out of 1st into 2nd. It sounds like a small dental instrument and tickles my fingers - in the way that doesn't make me want to laugh. Driving home (when I wasn't freaking out) I noticed that going from 1st to 3rd to 5th gave me the least amount of singing noise -- 2nd and 4th sounded the maddest. The gears themselves all work fine, it's when the shifter's moving around between them that I feel like I'm filing a tooth down for a crown. When I got home I cycled thru all the gears, and of course while not moving there was no dental sound. I should point out - the rival of this sound is sudden and unexpected - Trans had no warning quirks at all.

It may be a coincidence, but before I got in to drive away -- I noticed a car with a battered-up bumper parked about an inch from my front bumper. It was hard to imagine them not bumping into my car before they parked (but with no bumper marks I can't confirm). My car wasn't in gear when I parked it, just the brake was set - so could the 'near parker' hit me theory cause a change in my tranny…?

[Bob Kontak]

There is a plate on the side of the transmission that has a v-block fulcrum thingie on the inside. It is easy to remove and replace. Tilt the car so trans fluid goes to the far side.

Remove the plate, check the three nuts that tighten the block to the plate.

These "buzz saw" noise when transitioning gear threads come up occasionally and I am posting this as I had the noise, pulled the trans for a rebuild but before UPS-ing it to Mayo, checked the block and the nuts were loose. Note, I read on more than one thread that this can cause the noise.

Bummer is, I pulled the trans and had other issues that required the refresh, so I did not put the trans/engine back in to check if they nuts were the cause of the noise.

Mayo said the loose v-block and buzz noise was more of a problem with earlier 915's (before our's) and said the buzz noise was probably not from the block. They did not discount my thoughts completely, though.

Long story short, lift the car and tilt it so the trans fluid angles away from the port. Pull the plate and check the nut tightness. Replace. Top off fluid if necessary. Report back.

[wannaporsche]

Thanks for the quick reply Bob. I will definitely look into your suggestion and report back.

Searching forums with the words 'buzz noise' turned up another thread I'll post for interested parties…

Strange Transmission noises

I need to get the car to a garage -- Any idea how harmful this noise is to drive on if it's a loose v-block?

[Bob Kontak]

Probably ok for the short term. Just drive like a wimp, I guess. :-)

[pete3799]

My guide fork was loose ( very loose ) and did not hear any noise as you describe.

[Reiver]

Just a thought.
A throw out bearing going bad makes a rattle that emanates thru the tranny/shifter.
I adjusted everything and replaced all bushings trying to fix it.
Found it when I swapped motors and had ruled it out as the bearing only had about 25k on it...my bad.
The bearings rattle in their cage when worn and this does not affect your shifting at all until total failure.

[Bob Kontak]

Originally Posted by pete3799

My guide fork was loose ( very loose ) and did not hear any noise as you describe.

Same set up and mine was not "very" loose. One of the three nuts were snug.

[wannaporsche]

Thanks you guys for sharing your experiences…something I have very little of, especially with a transmission….

This is a very high, whining or sort of moaning sound that starts when sliding shifter out of 1st and into other gears, especially 2nd and 4th -- it's during the travel between gears. It sounds like there's a piece of metal traveling with the shifter mechanism that's rubbing lightly against the spinning parts. It's a very light metal contacting spinning metal sound that is a directly result of moving the shifter. Once in gear - no noise …

I'm having the guys at TLG in N Hollywood look at it 1st thing tomorrow, and will report back.

[wannaporsche]

Bob - you pegged it. Fork was loose, studs had worked their way out, shifter was moving about unguided. It's closed back up and working fine. I feel like I just dodged a major bullet. Thanks again for your feedback guys!

[Quinlan]

Just adding confirmation to this. My transmission was also "buzzing" between gears - intermittently.
When it did buzz or squeak, you could feel vibration through the shifter as the synchros did their work. Double clutching did not help.
I removed the plate with the guide fork and sure enough two of the studs had backed out a bit and the third stud's nut was loose, so the fork could move about. Not much, but it could easily be wiggled by hand.
I tightened everything up, filled it with gear lube and no more buzz!
Thanks Bob and everyone else!

[Trackrash]

Originally Posted by Bob Kontak

There is a plate on the side of the transmission that has a v-block fulcrum thingie on the inside. It is easy to remove and replace. Tilt the car so trans fluid goes to the far side.

Remove the plate, check the three nuts that tighten the block to the plate.

Long story short, lift the car and tilt it so the trans fluid angles away from the port. Pull the plate and check the nut tightness. Replace. Top off fluid if necessary. Report back.

I believe the plate is on the bottom of the trans. But good advise. Mine was loose also.