G50 Shift

UK Carrera · 01-10-2004, 07:07 AM

Hi All.

My car has covered approx. 46k miles. Had it now for only about 3 months and put about 2.5k miles on it myself. I changed the gearbox oil when I first got it to Mobil 1.

My question regards the gearshift, particularly 2 to 3rd. I've always put it down to the ham-fisted pilot but now I'm not so sure. Basically quite often when I change from 2nd to 3rd the lever is not as free to move as other changes and I get a sort of hefty clunk when I change, like a release of energy in the shift mech. Noise is not from the gearbox.

I was working on the theory that my clutch/shift co-ordination was out and I was basically winding up the mech.

Anybody any thoughts?

I'm thinking of replacing the lever bushings as a matter of course, but anything else I should be thinking of?

Many thanks.

twin plugged targa · twin plugged targa's Garage

Don't forget the shifter coupling, which is behind the seats on the shaft tunnel.
I would personally change all of the bushings and transmission fluid before going any further if the sound is not coming from the transmission.
When you remove the shifter shaft coupling mark/scribe where it was mounted before you reinstall the new then it will give you a starting point for you new adjustment.
If you do not mark how the old was adjusted then you will take forever to readjust to shift half correctly.
You can change just the bushings on the rear coupling but it is difficult to remove the old. I broke mine in the process and had to but the complete coupling.
Good luck
rgds Ben

dean · 01-10-2004, 01:37 PM

Maybe you should bleed your clutch first

kepperly · kepperly's Garage

Pull the shifter and replace the cup bushing and grease the cross shafts!

keith epperly 87 slant nose turbo look carrera cabriolet

UK Carrera · 01-10-2004, 11:36 PM

Hi Guys! Thanks for your replies - this board is always such a good source of help and info!

Dean - I'm intrigued by your comment. Can you tell me why you think I should bleed the clutch? Clutch was replaced by the PO about 9 months (and not very many miles) ago.

Thanks.

dean · 01-11-2004, 04:45 AM

Sometimes people forget that they should bleed the clutch as maintainance. If there is an air in the line, it could cause the clutch not to function correctly.

UK Carrera · 01-11-2004, 06:23 AM

Thanks Dean.

I assume that there is a separate mastercylinder for the clutch - i.e. separate to the brakes?

I'm planning on replacing discs, pads, and fitting some braided hoses in the next month or so. As part of this job I was planning to buy a Motive Products Power Bleeder (actually quite expensive here in the UK, butit'll earn its keep over a period of time), so I guess I'll do the clutch then.

ANy tips for bleeding the clutch?

Thanks.

dean · 01-12-2004, 05:24 AM

Yes there is a separate master for the clutch. You should have no problem with the power bleeder. Wihout the power bleeder it is a pain to bleed sometimes.
Jack the back of the car up high and sometimes you have to pump the pedal while bleeding.

KTL · 05:55 AM

I think I know the clunk that you are describing. Sometimes this clunk can happen when you start to move the shift lever ever so slightly to the next gear before the clutch has actually disengaged the power output to the transmission. So Dean's advice of bleeding the clutch is a good place to start.

You'll need a long length of clear hose and a little bit of patience getting the bleeding set up properly. I like to put a box end 8mm (or is it 7mm? Can't remember) on the bleeder screw first, then stick the hose on there. Don't open the bleed screw too much or you'll have brake fluid running down the side of the trans. Bleed screw leaks at the threads quite easily if you loosen the screw too much. Finally, a pressure bleeder is a very smart move for bleeding the clutch system. Manual bleeding doesn't work well. I've done it and it just doesn't work well on the 911.

BTW, the shift coupler on the G50 tail shaft is different than the 915 trans. There's pretty much zero adjustment back there. The coupler is a pair of flanges riveted together with a rubber pad in between acting as a damper. No adjusting allowable with rivets.

Do what Keith said and check out the shifter assembly. There's a hard rubber/plastic ball cup in there that wears out.

It's #10 in the picture. #2 sometimes wears out too. There was an article in Excellence, maybe a year ago, that detailed how to service the G50 shifter. I'll try to scan it when I get a chance.

UK Carrera · 01-12-2004, 09:01 AM

Fantastic - thank you!

Kevin - yep, think you do know the noise I'm referring to. Good description!

Once again, thanks.

kepperly · kepperly's Garage

remove #12 nut and #7 shaft and watch you don't loose #4 & 8 o-rings. If the shafts are rusty polish with 1500 sand paper and reassemble with good grease. replace #2 and # 10 plastic bushings. They are available from your Porsche dealer or from Pelican parts I think.

Keith

kepperly · kepperly's Garage

Opps don't forget to remove # 5 shaft and # 6 clip polish the # 5 shaft and reinstall.

Keith

KTL · 01-14-2004, 05:37 AM

Found the Excellence article last night. It's from the April 2002 issue. Didn't have time to scan it though. I'll get it on here eventually!

UK Carrera · 01-14-2004, 08:11 AM

Thanks All.

The Excellence article would be very welcome if you get a chance to scan!

UK Carrera · 01-15-2004, 07:44 AM

One further question - is there a source for part numbers, other than my local dealer of course!

Wil Ferch · 01-15-2004, 08:41 AM

One more thing....
*Do* recall that there is an achilles heel in the G50 design that wasn't fixed by the factory until April '89 production...the infamous actuation shaft support bushing issue. Will make the unit progressively stiffer to operate until it can't anymore.
Look at your receipts and if the clutch was replaced...this fix ( either with factory parts or aftermarket) should be shown too...or it will rear it's ugly head in -time.
---Wil Ferch

UK Carrera · 01-15-2004, 08:48 AM

Hi Will

Thanks for the heads up. Cuitch was done at an independent - no record of any update.

Can you tell me me more - or point me in the direction of more info?

Many thanks.

SRISER · 01-15-2004, 09:03 AM

No comment just marking so I can take a look at the scanned Excellence article...gotta do the bushings too!

KTL · 01-15-2004, 10:51 AM

Guess i'm really on the hook to get that article scanned..............

I'll get it tonight!

Here's more topics in which i've been involved regarding info. on the G50 issue:

Separation of Engine and G50 Transmission

Clutch release bearing - how does it work?

does an 89 930 need the G50 update?

This G50 stuff has been covered a few times before, so a search with any combination of the terms "G50, shaft, cross shaft, update, clutch, etc." should reveal some of the previous topics.

KTL · 12:23 PM

Article from April 2002

Anybody wants/needs full size images, let me know & i'll email them to you.

ktlspider"at"yahoo.com