Porsche Transmission Rebuild


The most noticeable performance decline in manual Porsche transmissions is the ability to shift easily / quickly / cleanly from one gear to the next---up or down. Syncro wear is most often to blame. Given worn syncros, shifting puts gears and dog-teeth at increased risk of damage, particularly if a driver does not shift-compensate for syncro wear. Should you experience any noticeable oddity when shifting, I recommend inspecting this condition sooner than later. Reason being, it's more economical to replace just syncro rings as compared to also replacing ruined gears and/or dog teeth.

        '09 model Porsches and up have electronic PDK shifting.

        Transmission oil in most cases should be changed every 15,000 miles. Do this regularly and you will go a long way to preserving the integrity, performance, and value of your Porsche transmission.


Porsche Clutch & Flywheel


Clutches & flywheels have a factory prescribed wear limit. Once beyond that limit, driving performance declines. You can extend the life of your entire transmission by driving it correctly. Not sure how to do that... Find out: 305-588-0874

Porsche 917 Long Tail line drawing shows top and side views of this race car's internal components

917 Long Tail

Click drawing to enlarge

Porsche 3.0 litre engine with 2 broken studs marked with yellow
3.0 Litre Porsche engine rebuilt with new ARP head studs

Top: Broken head studs are marked in yellow. Performance declines some from cylinder & heads held unevenly to crankcase. Precise flatness of head surfaces and cylinder faces can be beat out of spec as a result of operating an engine with broken studs. Bottom: ARP studs have replaced all old stock studs. An excellent upgrade as these will last indefinitely.

Engine rebuilds typically begin with a leak-down test. This provides insight to what can be expected during rebuild in regards to valve and piston ring sealing integrity. I can tell if a leak is at the intake or exhaust valve, or rings, or combination---this for each tested cylinder. Leak-down results seen above indicate cylinder #4 being best and #6 the worst. Differences seen here confirm this engine's lacking performance.

Leakdown test of Porsche engine results show unacceptable delta between #4 and #6 cylinders

One skilled person is capable of correctly & safely handling a Porsche engine during the entire rebuild process provided the equipment required is on hand. Here, a 3.2 engine rebuild has just been completed. GP is preparing to connect the engine and its' matching transmission prior to returning them as a unit to the Porsche on the lift.

Click photos to enlarge


Porsche Rebuild Parts - Aftermarket Parts


By default, genuine Porsche or OEM parts (when available) are used for repairs & rebuilds. If an owner prefers aftermarket, say so and consider it done when possible. If you have any question as to a comparison between a genuine Porsche part and the matching aftermarket part, ask... we'll discuss whatever part is in question and you can make the call, or leave it to GP if you prefer. GP's a steward of your budget and always wants to deliver optimal solutions for minimal expense, doing so with your input along the way.  

        Where classic Porsches are concerned, it's more of a challenge to find certain parts. Good news is there are resources across the nation and abroad so tough-to-find parts... can be found. 


Porsche Records / Documentation


Keeping accurate Porsche service & repair records substantiates the care given a car. Such records also provide very valuable reference when planning and engine rebuild / transmission rebuild. Or, working on any area of your car. Benefit being the potential for finding written answers to the questions that may arise before or while work is in progress. In short, the recommendation is: be a Porsche service record keeper if you aren't already. 

Porsche Racing


George Perdomo has GT and GTP class racing experience if you're interested. From the simplest of add-ons or refinements to your track Porsche, to extensive build outs for your class, you're in experienced race hands here. 

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Following Porsche's Le Mans victory in 1970 and '71, the company redirected their racing efforts to North America and the CAN AM series. Teaming up with the Roger Penske organization, the 917/10 was created with magneseum tubular frame weighing just 100 lbs and a 5 liter turbocharged 12 cylinder engine producing 1,000 hp. In 1972, the 917 was the most powerful racing car in history. On the track, it brought McLaren's CAN AM leadership to a decissive end. The successor to the 917/10 was the 917/30 (the engine increased to 5.4 liters.) In August of 1975, Porsche took the 917/30 to the Talladega race track in an attempt to establish a closed course speed record. With Mark Donahue in the seat, they did so on August 9, 1975 with an average speed of 221.12 miles per hour---a record that endured for 15 years... eventually broken by an Indy car. 

Air cooled Porsche engine thermal performance depends in large part on how clean the engine's exterior surface is. The cleaner the better as this allows heat to more readily escape the engine. It is up to my customer to decide what investment they make in "clean." Engine above has been degreased then media blasted. The alternative is to degrease only. Look at the difference below. Click on photo to enlarge:


The quintesential Porsche race car of the early 1970's was the 917 series. So dominating was the 917 that racing rules were specifically altered to put an end to Porsche's unrelenting track dominance.

Porsche Engine & Transmission Rebuild



Getting the most from your Porsche engine & trans is essential to the raw pleasure had from your Porsche. GP AutoWerks rebuilds Porsche engines to deliver the jaw dropping power Porsche's engineers intended. All rebuilds are done according to precise factory specifications per year & Porsche model. Want an even smoother, more durable, higher performance engine than Porsche designed? GP can push the envelope as far as you like, doing so within certain boundaries of course. In any case, each engine rebuild requires a clear talk-through. Before work begins, you can be sure being on the same page in terms of what you expect, your budget, and the time frame necessary for the rebuild session that's planned. Jump to Porsche Transmission Rebuild.


Comparrison of Porsche 3.3 litre engine before and after rebuild with restoration done by GP AutoWerks

Above: Same Porsche engine before and after GP AutoWerks rebuild. With most surfaces bead blasted and refinished with appropriate engine-area coatings (or left bare to match Porsche stock finishing) this engine rebuild is "with restoration"---an owner decision made at the outset of a rebuild. According to customer's goal in this case, work was accomplished to match a stock engine (for the period) as close as possible. 

Below: This engine came in running with a noticeable knock. Issue found: whomever had previously worked on this engine failed to install #4 rocker shaft correctly. This led to a binding of the rocker... then that rocker's valve & piston making contact. The crankcase is open here to make an internal inspection. While the problem was the rocker shaft, since there was piston & valve contact, everything that may have been damaged must be inspected so any & all issues are found and corrected. There is no exception to comprehensively inspecting for damage where I'm concerned. In this case, the valve, guide, rocker, rocker shaft, and piston were replaced for #4 cylinder. 

Porsche crankshaft is being inspected while it sits in engine case

Click photos to enlarge

What goes into an engine rebuild? After removing an engine from its chassis, a forensic inspection is done before cleaning, preliminary cleaning, careful disassembly noting any anomalies along the way, preliminary inspection of parts, meticulous cleaning, detailed inspection and measuring of parts, technical evaluation of what needs replacing and what can be machined in order to be intelligently renewed & reused, meticulous reassembly to Porsche factory specs or better, proper break in, first tuning, testing, final tuning, final testing. No short cuts. No distractions are tolerated during critical stages. When new parts are needed, owner is advised asap why and ahead of work proceeding unless GP is authorized having carte blanche in advance. Engine rebuilds done at GP AutoWerks are touched by ONE person only---GP/George Perdomo---start to finish. Experience & focus here ensures you getting peak performance and durability from the investment you make to renew your engine's Porsche-engineered performance.

       If you choose, GP can do things to make your engine rebuild better than what factory specs call for. Exactly what this entails depends on the goals you have in mind. In this regard, GP can help you understand & evaluate your options if you want. Ultimately, you'll have a clear picture of what can be done to your engine during a rebuild, what the added investment is, and what the added performance outcome will be.



Tolerances set by the factory for engine rebuilding... GP knows most by heart. Still, he always refer to Porsche's written Factory Technical Specs. This check-list process is similar to pilot procedures---even though pilots have done the same procedure hundreds or thousands of times, they still refer to a written checklist as GP does. The specialized nuances that make for an exceptionally fine engine rebuild... GP's learned his craft over 30+ years. A customer has said, "GP is old school but doesn't miss a new school beat." True.

      Porsche owners entrust their engine rebuilds and the dollars they invest to someone who's going to return exceptional performance value. That's what you'll get when your engine rebuild is under GP AutoWerks' authority. 

Special offer


If you're thinking engine rebuild, this is for you: Print this page and present it to GP when final payment is due on your Porsche engine rebuild, or transmission rebuild, or both. For doing so, you'll receive 10% off services. Candidly, if you're on the fence, this offer is a respectful nudge to add motivation to get on with it. Bear in mind this 10% is on GP AutoWerks services, not on towing, parts, or machining. Ahead of any work proceeding, you'll have a project scope and budget/estimate so everyone knows what's planned & expected. 




Endurance of your Porsche engine & transmission requires both areas receiving proper lubrication. This means:

  • Maintaining correct levels

  • Changing lubricants including filters on a regular basis

  • Using the correct lubricants for your particular engine & transmission

  • Adding oil radiator(s) for high performance driving

  • Maintaining clean oil radiators

  • Preventing / repairing oil leaks

The more frequently engine and transmission oil is changed (and filter) the longer your engine and transmission will endure within the tolerances Porsche engineers specified. 


Engine Tuning


Earlier model Porsches require manual tuning adjustments on occasion. Later model Porsches are computer controlled. GP is scanner savvy. In a nutshell, you're covered from nuts & bolts to digital bits & bytes engine tuning. 



For its time, the 917/30 was the most powerful car built and raced. It was a flat 12 cylinder 5.374 ltr that developed 1,100 hp at 7,800 rpm in racing trim.

Click photos to enlarge

Inside of Porsche transmission looking at syncros, dog teeth, and gears.

Above: Gears, dog teeth, shift rods, forks, sleeves and bearings are being inspected in this transmission rebuild. If any anomaly is found, it's photo-recorded and immediately text-sent to the owner. Comments on what is found is always provided an owner unless that owner has a standing order for GP to progress with repairs as found status calls for.

Right: New flywheel is installed with pilot bearing and new bolts---new bolts are standard procedure as old bolts, once removed, are stretched from the initial torquing and so will not correctly stretch again. Old "doughnut-style clutch disk compared to new spring-style. Doughnuts tended to explode making a mess of components in a transmission's bell housing. 

George Perdomo, founder & owner of GP AutoWerks, pulls Porsche engine on its stand
George Perdomo, founder & owner of GP AutoWerks, next to Porsche on car lift with Porsche engine in foreground

Transmission rebuild completed, the trans is connected to the engine with proper torque settings applied to fasteners. New oil is installed. Flanges on the drive couplings are cleaned and ready to receive the drive shafts/CVs with new gaskets.

New Porsche flywheel, flywheel bolts, and pilot bearing
"Doughnut" clutch disk compared to spring clutch disk

917 Long Tail

917 Short Tail

917 CAN AM Spyder




Porsche® Revive the Passion -
Open heart Surgery
Profile of 1982 Porsche 3.0 Litre engine after rebuild
Back end of rebuilt 1982 Posche engine
Porsche engine showing half blasted clean and half dirty
Two photos together - top is dirty Porsche engine heads, bottom is same Porsche engine heads cleaned
Clean Porsche crankshaft standing on end with connecting rods attached
Clean Porsche connecting rod assembly laid out in pieces includng rod top, bottom cap, two nuts and rod bolts, and bearings

Any and every mating surface on a Porsche engine/transmission rebuild must be very clean and flat. If not, the gasket applied is given the opportunity to leak. 

Porsche engine left side chain tensioner housing with chain, tensioner, and chain ramps installed
Porsche engine right side chain tensioner housing with chain, tensioner, and chain ramps installed

Video presentation courtesy of Porsche N.A. Permission on file.

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Porsche Community

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Miami Porsche Service, Repair & Rebuild Shop

GP AutoWerks

Miami's Master Porsche Mechanic

For Classic & Contemporary Porsche Sports Cars.


Disclaimer: Porsche, the Porsche crest, and Porsche car model names are under licensed use by Porsche Cars North America, Inc. (PCNA) from the owner Dr. Ing. h.c. F. Porsche Aktiengesellschaft, Porsche AG ("Porsche.") The PCA logo is the property of the Porsche Club of America. The "Porsche Museum" name is the property of Porsche. No association or affiliation with Porsche, PCNA, The Porsche Museum, or PCA is intended or implied by GP AutoWerks. GP AutoWerks is an independent Miami-based Porsche service, repair, rebuild shop that offers comprehensive master Porsche mechanical care for classic & contemporary Porsche sports cars. Credits: Videos are Porsche productions presented for educational & entertainment purposes only. Permission for presentation is on file. Editorial content/photos are indicated with black borders. Captions are provided to reflect photo content with credits appearing where due. Unless credited otherwise, photography is © 2015-2020 Karl Hansen. All rights reserved. Photos of Miami Porsche service, repair, rebuilding present the property of GP AutoWerks customers. All such photos are used with the expressed permission of GP AutoWerks customers. Website © 2015-2020 GP AutoWerks. All rights reserved. Website production: Karl Hansen 786-403-3991

 Miami Porsche Service, Repair, Rebuild Shop

GP AutoWerks

 Miami's Master Porsche Mechanic

 For Classic & Contemporary Porsche Sports Cars.