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California Motorsports Inc.

 928-855-5755

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993

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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

·         Trans type:  G50/20, G50/21

·         Origin:  Porsche 911/993 Carrera 2 1995-1998

·         Description:  H Pattern 6 speed manual transaxle with Borg Warner synchromesh w/synchronized reverse

·         Limited Slip Differential:  25/65% ZF LSD optional equipment

·         Drive flange size/CV overall diameter:  110mm

·         Weight: approx 145lbs

·         Oil Capacity:  approx 3.6L API classification GL5 75/90

·         Speedometer:  None

·         Trans controls:  Shift linkage

·         Remarks:  First and second use triple cone synchros

·         1st gear 3.82

·         2nd gear 2.05 (2.15 G50/21)

·         3rd gear 1.41 (1.56 G50/21)

·         4th gear 1.12 (1.24 G50/21)

·         5th gear 0.93 (1.02 G50/21)

·         6th gear 0.78 (0.82 G50/21)

·         Final drive 3.44, 7.5”

Gear chart, early G50/20 stock gears pdf

Gear chart, early G50/21 stock gears pdf

Gear chart, late G50/20 stock gears pdf

Gear chart, late G50/21 stock gears pdf

Gear chart, G50/31 stock gears pdf

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TRANSMISSION SPECIFICATION

·         Trans type:  G64/20

·         Origin:  Porsche 993 Carrera 4 AWD 1996-1998

·         Description:  H Pattern 6 speed manual transaxle with Borg Warner synchromesh w/synchronized reverse

·         Limited Slip Differential:  22/40% ZF LSD standard equipment

·         Drive flange size/CV overall diameter:  110mm

·         Weight: approx 180lbs

·         Oil Capacity:  approx 3.8L API classification GL5 75/90

·         Speedometer:  None

·         Trans controls:  Shift linkage

·         Remarks:  First and second use triple cone synchros.  Output to front diff via viscous coupler.  Can be converted to 2WD.

·         1st gear 3.82

·         2nd gear 2.05 (2.15 G64/21)

·         3rd gear 1.41 (1.56 G64/21)

·         4th gear 1.12 (1.24 G64/21)

·         5th gear 0.93 (1.02 G64/21)

·         6th gear 0.78 (0.82 G64/21)

·         Final drive 3.44, 7.5”

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TRANSMISSION SPECIFICATION

·         Trans type:  G64/51

·         Origin:  Porsche 993 Turbo AWD 1996-1998

·         Description:  H Pattern 6 speed manual transaxle with Borg Warner synchromesh w/synchronized reverse

·         Limited Slip Differential:  22/40% ZF LSD standard equipment

·         Drive flange size/CV overall diameter:  110mm

·         Weight: approx 180lbs

·         Oil Capacity:  approx 3.8L API classification GL5 75/90

·         Speedometer:  None

·         Trans controls:  Shift linkage

·         Remarks:  First and second use triple cone synchros.

·         1st gear 3.82

·         2nd gear 2.15

·         3rd gear 1.56

·         4th gear 1.21

·         5th gear 0.97

·         6th gear 0.75

·         Final drive 3.44, 9”

Gear chart, G64/51 stock gears pdf

 

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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!

 

·               Full transmission inspection

·               Full transmission overhaul

·               Ring and pinion setup

·               Gear change

·               Differential setup

·               LSD rebuild

·               Race prep

·               Prepare for inverted use

·               Re-register bell housing

·               Cut DME provisions in bell housing

·               Bore repair bell housing and center case

·               Main shaft straightening

·               Dog ring replacement, gear spot welding and honing

·               Internal spray bar oiling system

·               Custom MIG and TIG welding

·               Surface grinding

·               Throw Out Bearing boss/clutch release fork pivot shaft boss repair

 

1436

 

billet fork

 

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

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Turbo version with ring gear thrust screw

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.

 

·         993 billet side cover $425

·         993 Turbo billet side cover $499

 

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G50_TOB_repair

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.

 

·         $999 (installed price)

·         $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.

 

·         1st gear set (weld on type; requires core OEM input shaft; requires additional labor-not included in price) $995

·         2nd gear set $995

·         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:

·         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

·         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 Pdf.gif

G50/20 stock gears pdf

G50/20 with 3.10 ring and pinion pdf

G50/20 with 4.00 ring and pinion pdf

 

FITS 993 CARRERA 2, RS, CUP, RSR, G50/20/21/31/32/33

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clutch pack

 

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

·         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

 

 

AXLE FLANGES

 

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

 

993 1st 2nd dog repair

 

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

 

 

 

G50 dog ring

 

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.

 

·         3rd/4th/5th/6th dog ring $199 each

 

Fits Porsche G50 6 speed transmissions 94-98 C2/C4/Turbo

 

steel cage bearings

 

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