Ask a Mechanic: Used Volkswagen Golf GTI has clutch problems

Nov 02, 2023

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Dear Ask a Mechanic,

I recently bought a used (Volkswagen) Golf GTI which had been retuned. Didn't bother me; the car was relatively cheap in comparison to others on the market and in good condition, so any problems having to be rectified would bring it in line with its worth anyway.

It is very quick, but that comes at a price, it seems. When I’m in fifth or sixth and I put my foot down, revs jump up and my car acknowledges (on the display) that it's now in fourth. I’m pretty certain, given it's a manual, it's not dropping gears purposefully to increase acceleration, and I’m also pretty certain the tuning couldn't have instructed the car to do this either.

Am I looking at a new clutch?

I’ve already got it booked in to have this tune looked at and redone, but I gather that alone won't fix the problem.

Fly GTI

As you suspect, this is a clutch issue. Volkswagen does make a dual-clutch automated transmission for that model (called "DSG"), but, for all intents and purposes, it's an automatic in operation, and it's distinctly different from the manual transmission in your car. The manual gearbox is not capable of changing gears on its own, regardless of any type of engine computer programming.

The system that determines which gear you’re in for the instrument cluster display, does so by comparing engine rpm with road speed. As the gear ratios are known values, it's easy enough to calculate which one is in use — assuming there's no speed difference between the engine and transmission. When your clutch slips, the engine speed increases enough that the computer sees the rpm/speed relationship as best matching fourth gear.

If you’ve ever ridden a multi-speed bicycle, you’ll understand why in the harder, higher gears, clutch slip is more likely than wheelspin or acceleration.

Although there are other mechanical factors that could cause clutch slip, there are two scenarios that would be likely to explain what's happening with your GTI: Most probable is that the clutch is simply worn out from mileage, abuse, or just coping with the added horsepower, and the pressure plate is no longer capable of clamping the now-thinner friction disc tightly enough to transfer the engine's power.

However, given that the car is making considerably more power than it originally would have, it is possible that the clutch isn't worn or damaged, but that the clamping force of the stock clutch is being overcome by torque levels exceeding its designed capacity.

Returning the tune back to original might buy you time, but, if it has been slipping like that, the car will need a clutch sooner, rather than later.

Unless you’re keeping it stock, I’d strongly suggest using a stouter aftermarket clutch kit, not a factory equivalent replacement.

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