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PORSCHE 993
TRANSMISSION G50 6 SPEED
(prices and availability are subject to change
without notice)
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TRANSMISSION SPECIFICATION
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Trans type: G50/20, G50/21
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Origin: Porsche 911/993 Carrera 2 1995-1998
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Description: H Pattern 6 speed manual transaxle with
Borg Warner synchromesh w/synchronized reverse
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Limited Slip
Differential: 25/65% ZF LSD optional
equipment
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Drive flange size/CV
overall diameter: 110mm
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Weight: approx 145lbs
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Oil Capacity: approx 3.6L API classification GL5 75/90
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Speedometer: None
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Trans controls: Shift linkage
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Remarks: First and second use triple cone synchros
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1st gear 3.82
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2nd gear 2.05
(2.15 G50/21)
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3rd gear 1.41
(1.56 G50/21)
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4th gear 1.12
(1.24 G50/21)
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5th gear 0.93
(1.02 G50/21)
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6th gear 0.78
(0.82 G50/21)
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Final drive 3.44, 7.5”
Gear chart, early G50/20 stock gears 
Gear chart, early G50/21 stock gears 
Gear chart, late G50/20 stock gears 
Gear chart, late G50/21 stock gears 
Gear chart, G50/31 stock gears 
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TRANSMISSION SPECIFICATION
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Trans type: G64/20
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Origin: Porsche 993 Carrera 4 AWD 1996-1998
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Description: H Pattern 6 speed manual transaxle with
Borg Warner synchromesh w/synchronized reverse
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Limited Slip
Differential: 22/40% ZF LSD standard
equipment
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Drive flange size/CV
overall diameter: 110mm
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Weight: approx 180lbs
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Oil Capacity: approx 3.8L API classification GL5 75/90
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Speedometer: None
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Trans controls: Shift linkage
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Remarks: First and second use triple cone synchros. Output
to front diff via viscous coupler. Can
be converted to 2WD.
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1st gear 3.82
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2nd gear 2.05
(2.15 G64/21)
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3rd gear 1.41
(1.56 G64/21)
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4th gear 1.12
(1.24 G64/21)
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5th gear 0.93
(1.02 G64/21)
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6th gear 0.78 (0.82
G64/21)
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Final drive 3.44, 7.5”
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TRANSMISSION SPECIFICATION
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Trans type: G64/51
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Origin: Porsche 993 Turbo AWD 1996-1998
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Description: H Pattern 6 speed manual transaxle with
Borg Warner synchromesh w/synchronized reverse
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Limited Slip
Differential: 22/40% ZF LSD standard
equipment
·
Drive flange size/CV
overall diameter: 110mm
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Weight: approx 180lbs
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Oil Capacity: approx 3.8L API classification GL5 75/90
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Speedometer: None
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Trans controls: Shift linkage
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Remarks: First and second use triple cone synchros.
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1st gear 3.82
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2nd gear 2.15
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3rd gear 1.56
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4th gear 1.21
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5th gear 0.97
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6th gear 0.75
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Final drive 3.44, 9”
Gear chart, G64/51 stock gears 
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CMS 993 TRANSMISSION REBUILDING, REPAIR AND
MODIFICATION SERVICES
We offer a variety of services for your Porsche G50
transmission and would be happy to send you a quotation for any project
however large or small!
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Full transmission inspection
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Full transmission overhaul
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Ring and pinion setup
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Gear change
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Differential setup
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LSD rebuild
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Race prep
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Prepare for inverted use
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Re-register bell housing
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Cut DME provisions in bell housing
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Bore repair bell housing and center case
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Main shaft straightening
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Dog ring replacement, gear spot welding
and honing
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Internal spray bar oiling system
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Custom MIG and TIG welding
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Surface grinding
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Throw Out Bearing boss/clutch release
fork pivot shaft boss repair
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G50 6 SPEED/993 BILLET SHIFT FORKS
(all models)
The original forks are cast and sometimes break or
will simply wear out.
Billet forks are stronger, more reliable and are
commonly used in factory race transmissions.
- CMS 1st/2nd billet aluminum shift fork $250
- ALBINS 3rd/4th billet steel shift fork $595
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Non turbo
version

Turbo version
with ring gear thrust screw
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CMS G50 6 SPEED/993 BILLET SIDE COVER
The original differential side cover is made of cast
aluminum. Under load there can be a
tremendous force applied to this cover, and it can break, sometimes resulting
in a damaged ring and pinion-or worse.
Upgrading to a billet side plate will add strength
and increased reliability to the differential section.
Our cover features an oil passageway for diff
bearing and accepts the standard taper bearing, radial seal and O-ring. The turbo version further incorporates a
thrust screw to reduce ring gear deflection under load.
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993 billet side cover $425
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993 Turbo billet side cover $499

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CMS G50 BILLET T.O.B. (THROW OUT BEARING) BOSS
REPAIR
It’s not uncommon for the bosses that capture the
pivot shaft for clutch release fork to crack or break off rendering your clutch
inoperable. We can professionally
repair your bell housing for a fraction of what it costs to replace the
housing or the transmission!
Our new design allows the billet bosses to be
reattached to the housing without welding!
You will not find a cleaner more professional repair on the market
today.
$699 (not including teardown and reassembly
labor of the transmission)
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CMS G50 6 SPEED/993 BILLET SIDE SHIFTER CONVERSION
(all models)
This patent pending design moves the main shift
shaft to the side of the transaxle case allowing for a neat and tidy way of
attaching shift cables. Perfect for
some mid-engine installations and especially where space is limited behind
the transmission.
Shift cables can be attached or retrofitted to a
variety of shifters including the CMS billet cable shifter.
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$999 (installed price)
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$899 kit price (requires your gear housing and shift shaft)
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CMS G50 6 SPEED/993 BILLET END CAP CONVERSION
This conversion was originally designed for custom
mid-engine installations, and is useful when installation space is limited as
it will yield approx ˝ inch of additional clearance at the tail of the
gearbox. The end plate is available in two versions, with and without
the provision for the shift shaft. This also works well for some rear
engine applications. The conversion requires a different tail housing
to be used.
$495

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ALBINS G50 6 SPEED/993 GEARS
Stock gear ratios are designed for drivability and
fuel economy and not necessarily for best performance.
Whether you have a stock motor or one that has been
tuned your transmissions’ gear ratios may not be optimum for your driving
needs. Optimizing your gears to match
your engines’ power curves can make a huge difference on the track, often
resulting in reduced lap times, and can give the sensation that there has
been a gain in power. Alternative gear
ratios can make the car more fun to drive or be more drivable.
We carry a wide selection of OEM and Albins gears to
suit a variety of applications.
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1st gear set (weld on type; requires
core OEM input shaft; requires additional labor-not included in price) $995
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2nd gear set $995
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3rd, 4th or 5th gear set $995
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ALBINS G50 6 SPEED/993 FINAL DRIVE/CROWN WHEEL AND
PINION
The overall gearing in your transaxle can be reduced
or increased with alternative ratio final drive gears.
We offer OEM replacement sets as well as Albins made
sets-and in ratios that the factory never produced. These high quality hypoid gear sets are
produced on the same cutting equipment and with the same design as OEM.
Ratios currently available are:
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Albins 3.10/10:31 (special ratio for V8
and turbo applications, approx 11% increase in overall gearing – fits 2WD non
turbo gearbox only) $3025
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Albins 4.00/8:32 (improved
street/autocross/track ratio, approx 14% reduction in overall gearing – fits
2WD non turbo gearbox only) $3025
BREAK IN RECOMMENDATIONS 
G50/20 stock gears 
G50/20 with 3.10 ring and pinion 
G50/20 with 4.00 ring and pinion 
FITS 993 CARRERA 2, RS, CUP, RSR, G50/20/21/31/32/33
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KAAZ G50 6 SPEED/993 LIMITED SLIP DIFFERENTIALS
Help put your power to the ground more effectively
and add stability with a limited slip.
This is an improvement for a street car and a must for track car.
- 12 plate design
- High grade billet
steel housing
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1.5 way
asymmetrical ramps or 2 way symmetrical ramps available, allowing for 12
possible internal settings total
- Treated steel plates
allow for smooth and quiet operation
- Fits all G50 993 6
speed transmissions
Rebuild parts and services are also available.
EXPLODED VIEW
$1695
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ALBINS G50 6 SPEED/993 BILLET AXLE FLANGES
With big power and/or under extreme conditions the
output flanges on your transaxle can be a weak link. We have available Albins precision machined
case hardened billet axle flanges which have been a proven product in off
road racing for many years. These
flanges also promote more angular irregularity than the standard flanges with
deeper cups.
Note: Not for use with standard CV grease caps
$299 each
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CMS 993 1st or 2nd GEAR DOG
RING REPLACEMENT
It’s possible to repair your Porsche 993 manual
transmission 1st or 2nd gears instead replacing them
potentially saving you big bucks. When
the teeth are damaged or worn out the transmission usually won’t stay in gear
and may also grind going into gear-further indicating possible synchronizer
wear and shift sleeve wear.
The OEM teeth are welded to the gear and must be
machined off. The new teeth must be
fit and welded by an experienced technician.
We offer replacement both raw ready to install form or you can send
your gears to us to have the teeth replaced.
Replacement synchro teeth $295
each
Labor to R&R synchro
teeth $295 each
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ALBINS 993 SYNCHRO TEETH
Sometimes termed as dog ring or synchro hub, these are the teeth that the shift sleeve or “slider” engages into. If you have a
bad synchronizer ring and if you have been grinding going into gear-you
probably need to replace this part. Another symptom is that your transmission
won’t stay in gear.
These are a direct replacement for both
OEM and Albins gears.
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3rd/4th/5th/6th
dog ring $199 each
Fits Porsche G50 6 speed transmissions
94-98 C2/C4/Turbo
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993 STEEL CAGE BEARING UPGRADE
Beginning in late 1994 the factory used split type
plastic cage needle bearings for the idler gears. The shortcoming is obvious. Earlier generation G50’s used solid steel
needle cage bearings which have a more reliable cage with more robust
needles.
$179 each
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