Gearbox rebuild time

[wpozzz99zSS]

Not all C2's have the same set of gear ratios from the factory.

Obviously they don't, but see this attached link for the ratios of RS variants to G50-20/21 Carrera's.

http://www.gboxweb.com/993specs.html

There is considerable difference in the drive and you don't have to change all the ratios.

Of course, it may not make economic sense.

 

[Zingari]

:?: Interesting re the issue of going 1st to 2nd when cold. Can this easily be resolved then :dont know:

 

[clinchy993]

:?: Interesting re the issue of going 1st to 2nd when cold. Can this easily be resolved then :dont know:

Brian when I looked into the gearbox where the shift rods go through the casings there are recesses where debris collect around the shafts which is why I found it hard to select gears

Yes granted the needle bearings in the diff were being mashed but all the debris was being collected around the rods and scoring them ,I wish I had some pictures to show you

I am guessing in a healthy box you could drain + flush + re-fill

 

[adamw]

Glad that it's on the road to being fixed Tony :thumb:

 

[clinchy993]

Glad that it's on the road to being fixed Tony :thumb:

Thanks Adam :thumb:

 

[Nik]

...Quite interesting on how the selectors run though the casing and if you have trouble going from 1st to 2nd when cold you should see the crap that builds up in there

What do you mean by trouble going from 1st to 2nd when cold ?

If there is a problem, is there a reason why it should disappear when warm ?

 

[dapper]

Don't think there was the need for the rude 'obviously they don't'. Just making it clear to some less informed readers that even c2 models don't have a standard common gearbox, some were different in standard form, so not talking rs or c4 or any other variants.

 

[clinchy993]

...Quite interesting on how the selectors run though the casing and if you have trouble going from 1st to 2nd when cold you should see the crap that builds up in there

What do you mean by trouble going from 1st to 2nd when cold ?

If there is a problem, is there a reason why it should disappear when warm ?

Nik I am no expert but you could see where the debris made the smooth motion of the selector shaft tight ,maybe once warm the oil gets around those rods slightly better

Having driven a good few 964s and 993s and 1st to 2nd when cold seem to be stiff to engauge

My own car showed no signs for this but then again there were no signs that the box was goigt to fail before hand ,no noises no tough gear changes what so ever and I had been using it as a daily driver for the summer

I will get the old bits and photograph them so you guys can see the wear and scoring once car is done

 

[Nik]

Ok thanks for the reply.

So sounds like the symptom is the gear lever being very stiff to go from 1st to 2nd ?

 

[mohitos]

Don't think there was the need for the rude 'obviously they don't'. Just making it clear to some less informed readers that even c2 models don't have a standard common gearbox, some were different in standard form, so not talking rs or c4 or any other variants.

I think that's a factor of model year / date of manufacture, unless there was a factory option available to specify a closer ratio that I'm not aware of?

Mine was a late November 1995 build and so has the early closer ratio G50.21 transmission but with varioram engine.

 

[wpozzz99zSS]

Exactly, look at the link I posted earlier that shows the gearbox specification and date.

The strangest one is the Swiss box, the ratios are not ideal, but their noise restrictions are such that they needed to keep the revs and noise down to get through the tests at the time.

 

[madalaa]

..... don't like the sound of that one ......

 

[Senoj]

Glad its getting sorted :thumb:

 

[clinchy993]

Glad its getting sorted :thumb:

Getting a Parr warranty with the rebuild into the deal Dan and despite our chat I have gone with a Quaife ATB as it little more expense than the Porsche open diff

:thumb: :thumb:

 

[Nimrod]

Hi All,

When I bought my 2s a couple of years ago my diff self destructed and even when replaced 1st to 2nd was very stiff and not particularly pleasant.

As the car was just about still under warranty from when I first reported the problem the indi agreed to rebuild the box at cost price, it still wasn't cheap but the gear change is much improved and less resistance from 1st to 2nd. I choose to use slightly thicker grade oil so it still improves a little when warm but is definitely better for replacing the bearings, synchro's and generally cleaning out the oil channels as Clinchy describes .

I wouldn't have done it at full price until but I'm glad I had it done and I'm certain now that the change can be improved if not silky smooth when working properly.