Who has done a 923 Transmission (912E 7:31) Conversion ? I'm about to

[Blackbyrd]

Troubles in Paradise while being on a strict budget:


last week I was driving my 911 3.2 Euro swap SC equipped with a 915/68 (1984 Carrera) When all of a sudden I get on the Freeway off ramp and the transmission will not shift back into first when I stop at the stop light!

my first will not engage !

At first I think its the coupler but after many hours of messing with it, I find out it's much worse.... Long story short. I now plan to remove the transmission and swap it out for a 923/02 transmission from a 1976 912E with a 7:31 and 29:21 5th gear

I'm wondering if anyone else has done this swap.
Not just switching out the 7:31 Ring/pinion (electronic speedo type) and Taller 5th gear at: 29:21


I know the following items have to be swapped

- Main shaft (w/ matching 1st) due to the Difference in clutch hub Splines
- clutch guide tube
- release mechanism
- Side cover update to 79-86 type

I have yet to find a thread about switching out a main shaft


Option two 2 ??
I also read I can use a 70-71 type 911/01 225mm clutch disc
Then use my 915 flywheel ????






I have a Porsche Specific mechanic who will do the work for me
He will be guiding me through the whole process... so I will also learn something in the process

These were the other transmission I was selling for a client


top is 923/02
middle 915/70 (sold)
bottom is 915/63 (sold)

Its funny the 923/2 looks magnesium



So has anyone done a Swap ?

Experience of daily driving ?
Short cuts for the conversion ?

[john walker's workshop]

the diff housings are different. the guide tube does not swap straight across for a 915 tube. it would be a lot easier just to fix the dog teeth on 1st. you will get tired of the high RPM/poor mileage on the freeway with the 7:31 too.

[Matt Monson]

I'm with John Walker. You should be able to easily sell the 923/02 gearbox and get enough money to properly repair your gearbox unless something catastrophic happened like a hole in the case.

If you are going to use the 923/02, in addition to the other things you are considering, you will need to cut a chunk out of the case for the DME trigger point on the 3.2l, unless you did the engine swap with carbs or MFI.

And the 923/02 is magnesium. That's why it looks magnesium.

[Blackbyrd]

oops forgot to mention getting the transmission cut for the sensors.

So it is magnesium huh!
I though the 76 cases came aluminum.... guess thats what porsche did with the left overs


Mr Walker:

So even with the taller 5th gear the car will still waste more gas ?
Saving gas is a big thing for me since it's mostly a commuter car

Also you mentioned the guide tube is and can't be easily swapped ...this could be a problem, hence why I asked if anyone had done the swap before

Looking for experiences of people driving this set up
7:31 with a tall 5th

[john walker's workshop]

well, it's better than a short 5th, but the 7:31 will still wind up the RPMs. an 0.72 5th in a 8:31 is nice. 2500@ 60mph roughly, and mileage improved. got one in mine.

[Blackbyrd]

will see what happens ......

Here I was thinking this was a hot set up
figured Id be launching my car off the line keeping all the American muscle cars at bay

Ok fantasy over
lol


May have to go with just rebuilding my trans

[Grady Clay]

Save yourself a lot of aggravation and find an appropriate 915
or
rebuild your 915 to your own specifications.

The 923 may have some use but it probably isn’t in your 911.

Best,
Grady

[Matt Monson]

A 923 with a Wevo 916 tail conversion is many a 914 owner's wet dream gearbox...

[Blackbyrd]

After careful examination and the though of running a 7:31 for daily use....
I think I'm going to cross out the idea of running a 923 and just rebuild my 915/68transmission.

Dropping the engine/trans tomorrow and rebuild it over the weekend.

I have a Factory Oil cooler to add to it
Don't think I will do any other upgrades other than stock items....
No LSD to be found either so might just stick to what I have



Another thing to consider is... Im running 17in wheels and switching to 15in as soon as I can sell my wheels

I wonder if my gearing will slightly change with small wheels/tires

[Matt Monson]

Your gearing will change a lot with 15's. Buckley 15's for race cars have been the rule stretching "short ratio" option in production classes for years.

[Blackbyrd]

Final decision is not to use the 923 and instead just rebuild my own 915/68

It sounded so sweet to have a race type gear box

but since I will switch to 15in wheels it might make the gears even shorter ...ugghhhh