RubeGoldbergJr

Did you have to remove any body panels in order to facilitate the gear oil change? If so double check the tightness of the fastening bolts.

ComradeStan

That's the first thing I checked. Re-tighten all the supporting bolts at 48lbs. Did not make any difference in terms of noise.

deilenberger

I'll just comment -

I owned an '02 M3 convertible - noted for being balky 1st-2nd gear shifts when the transmission was cold (quite common on the Getrag 6 speed). RoyalPurple had oil they claimed was WAY better than stock oil and would make the balky go away, so I swapped the RoyalPurple in. It all seemed good - it shifted easier 1st to 2nd when cold, until I drove it alongside a "Jersey barrier" with the top down and the windows down. The noise the transmission made was unreal. I went back to the stock oil (I believe 75W-90 GL4) and the noise diminished to a normal level. I did a flush with the correct oil before the final fill.

And many transmissions are noisy inherently - back when I owned an XKE - I removed the transmission tunnel top to get to the speedo right-angle gear. While it was off - and I could see the top of the transmission - I drove it to check if things were working. The amount of gear whine in the cabin was astounding. I put the cover back on - and the padding/carpeting on it - and the noise went back to normal levels.

So - really two things - use the correct oil. Make sure all your usual coverings are in place.

Might not apply - but it might and they're easy to do.

ComradeStan

Thanks for the feedback everyone. I wasn't able to get a better recording. I even taped a voice recorder near the transmission but the quality was horrible. I need to figure out a better way to triangulate and record the noise while the car is moving. If you guys have suggestions, let me know.

Once I confirm the noise location, and if it's indeed coming from transmission:
1. Reflush with Delvac (just cause I have another jug of it already) ... this will tell whether something got stuck somewhere and perhaps a flush will dislodge it.
2. Reflush with proper porsche gear oil

CrisTSC

The noise shouldn't come from the oil itself. At least not immediately after the oil change, no matter the oil type. The only possible explanation is that some dirt moved around...
I have changed the oil in my MT .2 Cayman. Silky smooth and no noise before, the same after the change. I have used Shell Spirax S5 ATE 75W90, as it is a GL-5 oil and has (had?) Porsche approval, the only one available over here.

ComradeStan

Alright, today the noise was there when I was stopped. In neutral. I suppose the good news is now I can hopefully recreate it while it's on the lift or something.

I don't think I've heard it in neutral before. Although the car is now fully warmed up. Perhaps it's more evident when it's at temp?

​​​​​​Good data point.
​

hueyhoolihan

not a whole lot moving in a transaxle on a manual when in neutral, although i think the input shaft is turning as long as your foot is off the clutch.

BTW, i've got a similiar noise under similar conditions on my 2007 2.7l cayman manual. sounds like a wooden pencil vibrating at rpm speed on the bottom of a wooden desk drawer. only when up to temp and under some load. i can make it go on and off with some acceleration/deceleration. so subtle i can't hear it above the AC or cabin fan, not to mention stereo. driving me nuts...i'm praying it's a chain tensioner pulley bearing going bad. can't make a noise when mine is in neutral no matter how hard i try. i've looked at that pen in the glove compartment countless times. i need to get someone else to drive so i can hunt down the noise.

ComradeStan

@hueyhoolihan , yeah the foot is off the clutch.

Got myself a cheap stethoscope and put the car up on quickjack. EVERYTHING is loud. I think I've spend first 10 minutes just randomly listening to things. Pretty cool. Also, my ears are hurting from wearing the damn things.

As far as I can tell, putting the needle (stethoscope) on the transmission, does not amplify the sound. Other than that, no conclusive finding as I had to shut down the search early and do things that are also exciting for the rest of the family.

Off the topic, do you guys usually take the wheels off when the car is up on the lift for extended periods of time? Probably not a 'normal' case for the wheels to be hanging off.

hueyhoolihan

*delete*

zuch

I put mine on a 4 post lift and inflate the tires to max if I'm going to store the car on the lift for an extended period of time. I don't believe long term storage on a 2-post lift is ideal for the suspension.