G50 Gearbox synchros

[fransdecourt]

At normal revs it's a very crunchy exercise to change especially from 1st to 2nd gear.
Are there any remedial solutions or do we have to rebuild the box?
Being a 100k mile car, should we replace 'everything' that moves or just those parts, which are worn?
Anything else please, that I should consider doing once the gearbox comes out?
Thanks and cheers from N.Z.

[fransdecourt]

With replacing some of the internal parts, is it important to stick to genuine Porsche or can we use aftermarket?
And if so, what brands would you suggest please?

[Maxhouse97]

Beware on steel synchros from Porsche - I've heard they recently changed suppliers and have had quality issues with the new parts. Matt from GT could speak more intelligently about it, but my mech had to find some old ones that were still good.

[johnsjmc]

I was convinced my syncro was shot on 1st but it works perfectly again after changing the clutch and greasing the input splines ,112000 mi
.The clutch was dragging . 100k is low for worn out syncros on a g50
How many miles on your clutch?

[ganun]

Yep look at simple things first, bleed the clutch, have fresh oil in the trans, I like Redline NS in my 87 G-50 BIG difference in shift quality. Pedal travel also.

[Matt Monson]

I always recommend replacing parts as assemblies. If it is in your budget, get a new 1/2 slider hub assembly in addition to the 1st and 2nd gear synchros. If you aren't racing the car and downshifting into 2nd,you don't need the steel version there.

As mentions stick with OEM at a minimum. The dealer brass synchros are OK. I probably wouldn't trust their steel version. And above all else don't buy the cheap knock of R&S versions you can buy for 75 cents on the dollar of what the OEM ones cost.

[fransdecourt]

Thanks for all the advice, much appreciated.

The car has done 110,000 miles, so just run in!!

Interesting to hear about the Clutch option and the Input Splines, etc. It sounds like we could certainly start with looking at these options first.

Will ask one of the 'specialists' to take it for a drive and see what they say.

[turbobrat930]

Another source is Jim Patrick at Patrick motorsports. I bought my race prepped G-50/50 box from him. Great guy to deal with

[johnsjmc]

Originally Posted by johnsjmc

I was convinced my syncro was shot on 1st but it works perfectly again after changing the clutch and greasing the input splines ,112000 mi
.The clutch was dragging . 100k is low for worn out syncros on a g50
How many miles on your clutch?

There is a special grease speced by Porsche for the input splines ..I used the small packet supplied with the new Sachs clutch. Wire brushed the splines .The clutch drag is almost imperceptible except the stick would be hard to pull into neutral at times and the car would move slightly while starting it in gear with the clutch pedal pushed down. I changed the master and slave cylinders ,then the motor mounts all of which helped but it still crunched shifting into first until I changed the clutch. I,m very glad I didn,t rush into an expensive trans rebuild. If you have weak syncro issues in all gears I would suspect this for sure, I was fooled by it only seeming to be 1st gear which crunched ,but now all gears engage better and the crunching on first has stopped completely.
It,s a fairly common issue with a 100,000 mi clutch. I found the original 1994 dated assembly in my 95 when I changed it last winter at 110000 mi. and the splines were very dry and rusty. rennlist has a number of threads referencing dragging clutches on both 993 and 964,s

[OsoMoore]

Originally Posted by Matt Monson

I always recommend replacing parts as assemblies. If it is in your budget, get a new 1/2 slider hub assembly in addition to the 1st and 2nd gear synchros. If you aren't racing the car and downshifting into 2nd,you don't need the steel version there.

As mentions stick with OEM at a minimum. The dealer brass synchros are OK. I probably wouldn't trust their steel version. And above all else don't buy the cheap knock of R&S versions you can buy for 75 cents on the dollar of what the OEM ones cost.

Seconded. My 915 synchroes from R&S had to be sent back and I lost a week of summer driving waiting for new OEM ones to arrive.

[fransdecourt]

You guys are truly awesome. I have taken note of all your suggestions and advice. I'm not technical enough to tackle the gearbox or clutch myself, but with this new knowledge in hand I will now visit a couple of Porsche 'specialists' and see what they have to say, after driving the car.

[pc100porsche]

Where in Nu Zulund are you located ?

[Matt Monson]

There's Motorscience and Powerhaus who are both perfectly capable of servicing a G50 for you.

Regards,

Matt