020 Transmission 5th Gear Conversion

As everyone with a '83 or '84 GTI knows, the close-ratio transmission that came stock with the car is geared pretty low. If you drive your car on extended trips, the constant droning of the engine at highway speeds can become pretty tiresome. This is not particularly a shortcoming, as the original GTI was praised by the motoring press as having perfectly spaced gears, but being able to cruise at 70 mph without abusing your ears is a plus to some.

There are a couple of ways to fix this problem, one of which is to replace the transmission with a wide ratio unit from a garden-variety Rabbit or Jetta. If you've modified the engine to the point where you've got plenty of torque and power, then this is most likely the easiest route to take. However, if you're at the point where you're working with a stock engine, or one with the basic bolt-ons, then leaving 1st through 4th alone and replacing the 5th gear with a .75 unit may just be what the doctor ordered. In this instance, your acceleration will be preserved for the usual stop light battles, but you can cruise with pleasure on the highway.

So, what does the .75 conversion do, you ask? Well, it drops the engine RPM while in 5th by an additional 500 rpm or so. This means that there will be about a 1000 rpm drop between 4th and 5th gears, so if you shift from 4th at about 45 mph (approx. 3,000 rpm), you're going to be dropping your engine down to about 2,000 rpm. In an area with a 45 or 50 mph speed limit, this is somewhat annoying. Where the dividend shows up is on the highway, where 65 mph is at about 2,900 rpm.

So, the big question is: "How do I swap my 5th gear?" Well, you've come to the right place. For starters, this conversion can be done with the engine and transmission in the car, but in the long run, the best way to do it is with the transmission pulled. The side benefit is you can replace the crankshaft main seal, clutch output shaft seals, pressure plate, clutch disk etc. while your at it. The dangerous part about performing this task with the transmisison in the car is it is very easy to let the 5th gear selector rod slide out of it's tube, letting the shift forks inside the transmission fall out of place - then you'll have to pull the transmission, take it apart, and put everything back in position.

The conversion kit should come with the gear itself, a special tool, a sychronizer bolt, thrust washer, circlip, a gasket, and a new transmission end cap. The last time I checked, the cost of this kit was about $230.

When reading the procedure, refer to the exploded view of the transmission below, and you'll have a good idea of what I'm talking about. At this point, I'm going to assume you've got the transmission out of the car or in a position where you have access to the small end of the unit. This is where the 5th gear is located. Set the transmission up where the bell housing is pointing down, and the narrow end of the transmission is pointing straight up.

DURING THIS WHOLE PROCESS, REMEMBER - DON'T LET THE 5TH GEAR SELECTOR SHAFT FALL OUT OF THE TRANSMISSION!

This should give you a good idea of what's involved in the conversion. Typical shade-tree mechanic time is about 2 days.