G50 trans/shift noise- no answers in "search"
 

Hi All, I have an 87 M491 Carrera with a G50, 60k miles, and generally well cared for. I don't recall it making this noise when I first picked it up 2 years ago, but I may also just be more sensitive. I also just had it in to a good local shop (S Car Go Racing) and could point out the noise on a test drive- the very experienced mechanic checked out everything he could think of without tearing into it (opened a hatch in the back seat...) and could not figure it out- said he did not think it was the trans.

The noise is only during specific conditions- slowing down with some back-pressure at around 2300 rpm. It's somewhere between a buzz and a grind, but not really a mechanical grind you would get from gears- more like something vibrating and touching. It also sounds like it's coming from the area under the gear shifter, not from the rear/trans!

Any ideas appreciated!

Could be a number of things. First off, I'm going to assume you still have the original rubber centered clutch disk.

Does the noise change when clutch is disengaged?

Does it change if the car is idling in neutral and you start to push the gear lever into first (without stepping on the clutch pedal and without actually engaging first)?

Does your shift rod have the rubber band o-ring?...

http://forums.pelicanparts.com/uploa...1612368799.jpg

Later G50s also got an updated clutch slave cylinder and a brace, 950 301 401 00, between the trans case and heat exchanger, #24 here...

http://forums.pelicanparts.com/uploa...1612370114.jpg

Also, this...

http://forums.pelicanparts.com/uploa...1612368955.jpg

Thanks Frank, you are always a wealth of information! I'll take a look at your recommendations.

Honestly, the noise it not really a rattle- driving around with the mechanic I got him to drive down a hill with the clutch engaged (using the motor to decelerate), and in 2nd or 3rd at about 2300 to 2500 rpm and foot off the gas we could duplicate the noise- you get it slightly accelerating if you are too low on rpm's/lugging. Certainly no "rattle" at idle, clutch in/out or any other situation... I'd guess the noise is generated by a specific harmonic vibration.

Thanks, Sebastian

I have the same sound from my 87 after replacing my shifter cup a few years ago and couldn’t figure out how or what to adjust to get rid of it. I’ve had the console out since then to replace AC switch, but that buzz was still there after it was buttoned up again. I’ll be following for advice on what else to look for but like you it sounds like it’s coming from the shifter “stack”.

I'd definitely take a look at the bushings in the shifter.... may be metal on metal noise. Order the bushing and cup and just replace them since you'll have the console out. Probably time to do so. Had to change them out on my '88 and it only had 34,000 mi. at the time.

I just ordered a Porsche JWest Engineering G50 Shifter Bushing Kit, sounds like a good place to start!

I had the intermittent buzzing in both my '70 VW and the '88 Carrera's stick shift area. Fixed both by replacing the plastic bushings. I think you're on the right track.

Are you doing the JWest hard plastic shift coupler too, or just the bushings?

The kit comes with a coupler I think... bad idea?

https://www.pelicanparts.com/More_Info/JWSTG50BUSH.htm?pn=JWST-G50-BUSH&SVSVSI=0814&DID=26273

G50 Rattle
 

You should also review the G50 Rattle thread which includes an article Rattle Trap from Excellence on Carrera G50 rattles.

Edit
MBEngineering posted the TSB on shifter rattles in this thread Post 10, Is a chattering sound normal starting out in 1st gear? '88 Carrera.

There is an adjustment spec for the G50 linkage. Post #3 here...
http://forums.pelicanparts.com/porsche-911-technical-forum/993071-g50-stuck-2nd.html

Nope. What you ordered is good. If you were going to go for this...
https://www.pelicanparts.com/More_Info/JWSTG50CPLR.htm?pn=JWST-G50-CPLR
...I was going to suggest holding off. At least until you've sorted your current issue.

i assume the mech.checked your transmission oil level?..
As Famo.said you most likely have the original clutch assembly which has the rubber clutch disc.
It could be your problem since it is an original disc since 1988....
Also can you make a video with sound of the noise?

Ivan

I appreciate all the feedback!
I recently changed the trans fluid and the level is good, and the mechanic checked out the linkage in the back seat hatch and felt everything was optimal. I just checked ut the shift lever, and everything feels rifle-bolt tight and smooth.
I'll start by loosening and tightening the motor mount brace and then installing the new shift kit- see how that works.

Thanks, Sebastianhttp://forums.pelicanparts.com/uploa...1612470765.jpg

Good looking car... the M491 is a rare bird. Enjoy it!

So I actually did get a video- let's see if I can upload it. I also tried holding on to the shift lever and exerting some upwards force during the same scenario- no noise. I think the shift bushing kit will fix it... let's see.

SebassSF,
I saw this in the PCA e-news
it maybe helpful
https://www.hagerty.com/media/maintenance-and-tech/make-your-porsche-shifter-feel-like-new-in-one-weekend/

After installing the Wevo PSJ, I have a similar noise to what you are experiencing but the noise is expected with the PSJ.

I think famoroso nailed it in the post provided above with regards to the o-ring. Personally I would just install the Wevo PSJ and live with the noise as it makes a big difference with the shifting precision.

I bought the G50 kit and it sat around waiting for me to install it. Had to take the car in for some work and got them to install it. Transformed the way the car shifted. Definitely recommended. BTW, when I picked up the car, I got the look from the service manager, he said it was "fun" to install... If you search through 911 technical forum, there are lots of tricks to get it to fit.

My trans makes all kinds of noises. I let the service manager take the car for a day, he said no problems. His sounds the same.

Thanks as always for the great feedback! First of all, I did shoot and post a video: https://www.youtube.com/watch?v=kM06P-lu_ak&feature=youtu.be
And, fixed the problem! I installed the shifter bushing kit (not a hard diy) and the noise is now gone- I guess people refer to the noise as a rattle, and although it was never there at idle (only 3200 rpm) I guess it's the same issue. When I got things opened up, there was quite a bit of rubber gumming things up (see pics) but everything felt smooth. I think there was a bit of play in the bushing that the shaft goes through but not much. There are also two "cables" that run through the tunnel that were close to each other- just touching in some spots that I zip tied together because they felt like they could have been vibrating against each other. Went for a nice drive yesterday and much better knowing it's not a transmission issue!

http://forums.pelicanparts.com/uploa...1612794636.jpg
http://forums.pelicanparts.com/uploa...1612794636.jpg
http://forums.pelicanparts.com/uploa...1612794636.jpg

Great article!