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Audi tt rolling in gear

I have a 2002 audi tt that rolls almost freely when in gear . Very little incline needed . Car appears to drive okay. Not sure when this started as I’ve always used park brake . My mechanic mentioned it to me after replacing turbo downpipe , he said he had to remove front axle to do it . Prior to that a motor mount was replaced the dog bone one I think. Please i dont know what caused this . I’ve had standard cars before and compression was more than enough to hold car with not much incline

There are a few possibilities.

If you have an automatic transmission, you probably have a broken parking pawl.

If you have a manual transmission, you’re either putting it in too high a gear, you have a loss of compression, or both.

The best gear to use to park a car with a manual transmission is the lowest gear, which is usually reverse. If you’re putting the car in a higher gear, you make it easier for the wheels to turn the engine, so make sure you’re using reverse or first gear, not a higher gear.

What I don’t understand is, if you’re using the parking brake, why is the car moving at all? Leaving it in gear should only be a backup for if the parking brake fails, but regardless of whether your engine has enough compression to hold the car, your parking brake should be enough to hold the car without leaving it in gear.

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Tell us exactly what’s happening. What gear is it rolling in? Engine on or off?

It’s a standard 6 Speed and of course I’m putting it in first gear. If it was a compression issue would it still drive fine? I’m referring to the Past as far as I can remember I use the parking brake and left it in first gear when I park the car but it seems to me it should not be rolling when the engine is shut off it’s left in first gear and there’s very little incline I understand a very Steep Hill might make it roll but this is not anywhere near steep

It is rolling without the parking brake on seems to me it never used to do that and certainly other cars I had that were standard first gear engine shut off the car would not roll

So it’s a manual transmission, and with the engine off it rolls easily in first gear? Does it drive ok? If it drives ok, then maybe the engine compression is poor. How many miles on it?

I only took it for a brief Drive and then left it with the mechanic after I learned of this issue. I took it about a mile up the road and back went through the first five gears easily couldn’t feel any slipping and it seemed all 225 horses we’re still under the hood

130000 kilometres

Many years ago, I owned one of GM’s X-cars, a manual shift Chevy Citation. After replacing the rusted e-brake mechanism twice, I opted to not repair it a third time, and so I had to rely on putting the trans into gear when it was parked. The car was about 5 years old at the time, and although it drove “okay” (or, as well as that piece of GM crap was capable of operating…), if I was parked on even a slight incline, the car would “inch” ahead a bit when in gear, clearly as a result of failing compression. Out of necessity, I got into the habit of bracing a tire against the curb.

So, based on my experience, I think that a car can continue to drive “okay”, even with reduced compression.
:thinking:

These are my concerns as I’ve research this on many forums some of the things that are mentioned as possible causes the list seems similar to work I’ve recently had done on the car. One person quoted potentially motor mount which I’ve recently had one replaced another says leaky intake or exhaust valves and I’ve recently had the turbo downpipe replaced with a flex pipe the mechanic custom built for the car. So I wonder if when the car is running compression is fine as soon as I turn it off the newly-installed flex pipe could be leaking

I see no reason any of those repairs would have anything to do with this. It comes down to compression and gear ratio.

I recall at least some early factory turbo cars having a lower mechanical compression ratio than their normally aspirated counterparts. OP stated she normally uses the parking brake and first gear without a roll away problem. She is concerned because the mechanic demonstrated he could easily push the car in gear with parking brake off. Maybe his boat payment is due and he had the car in third gear?

A 17 year old car is likely to have worn piston rings, particularly on an engine that is driven hard, so replacing valves might or might not fix it. It would drive fine due to engine oil helping form a seal when the engine is running. When the engine sits. No oil is being circulated to maintain the seal at the piston rings.

And possibly a worn, slipping clutch on this aged car?

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That’s why I asked how it drives. If the clutch slipped with the engine off, it would slip like crazy when driving.

The OP says “car appears to drive okay.”

Right, so I’m guessing it’s low compression, not a worn clutch.

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So we’ve narrowed it down to rings or valves? What else could cause low compression, a leaky head gasket perhaps?

I hope and pray that the one axle that was removed was reinstalled properly or it most certainly could cause this issue.

Your TT is predominantly a FWD vehicle with a viscous coupling that can engage the rear wheels on demand…

So if it is basically FWD when sitting still and I removed one of the front axles and handed it to you… I bet the car would roll easily. I could be wrong about the aggresiveness of the viscous coupling but I do not think I am at present… and if this is so… you have a Fwd car with possibly one front axle engaged in the equation.

Just saying that it is possible to induce this issue…esp if it wasnt doing this before and a front axle was removed and Voila it began to occur.

That is where my eyes would be…

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Good idea, I didn’t think about the AWD. First place to look.

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