5TH GEAR TRANNY CONVERSION

 
While the stock close-ratio gearbox provides nice acceleration in 5th gear, it does so at the expense of noise and fuel economy.  This might not bother some people, but those that drive in 5th gear alot will enjoy changing to a taller 5th gear. Need quick acceleration? Downshift to fourth!
 

This page is meant to assist you in changing your 5th gear, but is by no means complete installation instructions.   The instructions that come with the Autotech 5th gear kit are incomplete and inconsistent, and obviously not written for the novice. Using the Autotech instructions, along with VW Trends Magazine (March 1997), Greg Raven's "Volkswagen Performance Handbook," the Bentley Service Manual, and email assistance from an experienced friend, I successfully accomplished the 5th gear swap.

This 5th gear swap, specifically a .75 into a 4k transmission,  was done with the transmission out of the car. Those doing it in the car, will need to lower the transmission to gain access to the 5th gear/clutch release bearing housing (aka "end cone"). Don't forget to drain the transmission fluid!

Fifth-gear kit - contains everything you will need!

click pictures for larger version in a new window

Begin by removing the end cone. Remember to not the let "selector rod" fall out.  If this happens, you will have to disassemble the entire transmission! 5thgear1s.jpg (17024 bytes)
Here is a photo of the 5th gear assembly. Don't be intimidated, it's not as complex as it looks. 5thgear2s.jpg (10072 bytes)
A 12 point driver is used to remove the bolt from the mainshaft. This is the same tool used to remove the head bolts, so buying one is a good investment.

A "special tool" is included in the kit. It is used to unscrew the tube from the 5th gear shift fork.

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To remove the 12pt main shaft bolt, you will need to keep the main shaft from turning.  This can be accomplished by (1) having someone press the brakes if in the car, or (2) by engaging the tranny in 5th and reverse gear if out of the car.

To engage the 5th and reverse gears, you will need to remove the selector shaft lever, remove the reverse/upshift light switch, remove the selector shaft cover (27mm hex), and remove the selector shaft retaining bolt. The selectory shaft shaft will now easily slide out (to the right in the picture).  Now is a good time to replace the selector shaft seal.

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With the selector shaft removed, look through the reverse/upshift light switch opening.  You will see four small levers. Press the 1st and 4th levers down to lock the transmission in gear (I believe they are the 1st and 4th, but you should be able to figure it out).

With the transmission locked in reverse and 5th, remove the main shaft 12 point bolt. Return the transmission gears to neutral.

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Measure the threaded portion of the selector rod tube exposed above the shift-fork (approx. 5mm). Next, pry up the shift-fork locking plate using a flate head screw driver. Using the "special tool", unscrew the selector rod tube. You will now be able to remove the 5th gear cluster. Pay attention to how it is assembled for when you put it back together. If possible, keep the 5th gear cluster together as one unit. 5thgear3s.jpg (12977 bytes)
Using two flat head screwdrivers, carefully pry up the 5th gear cluster.

Remove the circlip on the small 5th gear, and carefully pry it up using the two screwdrivers. Circlip pliers are suggested for removing/installing circlips. ($16 from Sears)

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At this point, the small 5th gear and 5th gear cluster have both been removed from the transmission.

These two pictures show the old and new gears.  The top picture is the small 5th gear. The bottom picture is the 5th gear cluster.

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5thgear9s.jpg (8741 bytes)
 
Clean the new gears using a non-flammable solvent.

Heat the new small 5th gear using an oven or propane torch. Install  the new small 5th gear and new circlip.  If needed, carefully tap it on with a rubber mallet.

Reassemble the 5th gear cluster using the new gear and washer.   Reinstall the cluster. You will need to screw the selector rod tube using the "special tool" until the selector rod tube is exposed above the shift-fork approximately 5mm or the amount measured when you disassembled it.

Tap the shift-fork lock plate back in to position to secure the selector rod tube.

Lock the transmission in 5th gear and reverse gear again.   Install the new 12 point bolt using red "Loctite" and torque it to 111 ft. lbs. Return the transmission gears to neutral.

Reinstall the selector shaft and selector shaft lever.   Using the selector shaft lever, "shift" through the gears (mainly 5th) to make sure everything moves properly.

Install the new gasket, and reinstall the end cone.   Torque the bolts to 18 ft. lbs.

Be sure to refill the transmission fluid before driving.   Now is a good time to switch to Redline MTL.

 

Enjoy the quiet ride!

Many thanks to Virtual World Parts for supplying the Autotech .75 5th gear kit.

 

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