Hello there

I have a 2006 T5 2.5l TDi 130bhp (145k miles). The engine ceased a few
months ago, shortly after putting petrol in instead of diesel (duh). I ended up having the engine completely remanufactured for the princely sum of £3,700 (they also replaced the flywheel and clutch kit). When I got the van back it started to shudder very badly - usually around 1600-2000 rpm. Took it back and was told the air mass meter had failed, so I replaced that. Shudder continued. Took it back, they replaced all the engine mounts and fitted another new flywheel and clutch to be safe.

The shudder didn't go away. They did notice a little bit of excess play in the drive shaft (a few mm), but basically the mechanics are at a complete loss as to what is causing the shudder. Their current theory is that it is likely to be the gearbox. What they think might have happened is as follows. They reckon that when the engine ceased, the forces involved might have had a major impact on the drive shaft (hence the excess play) and subsequently b*****ed up the internals of the gearbox to some degree.

The shudder appears to kick in in all gears, but is very noticeable around 1500-2000 RPM in 3rd gear and up. Particularly when going up hill or when putting my foot down for quick acceleration. The mechanics have basically suggested to monitor it for a while to see if it gets worse, as that might help pinpoint the exact cause of the problem. Whilst this makes some sense, I am very worried everytime I accelerate the van. The van should have heaps of power but because of the shudder it performs sub-optimally.

In addition, the van has been starting very badly and failed to start completely today - however, this is probably to do with the starter motor, so hopefully that's a relatively quick fix and probably unrelated to the shuddering?

Could anyone shed some light on what might be wrong and what to do next? Also, if it is the gearbox - what sort of cost am I looking at and should I replace it asap or wait for matters to deteriorate?

Any views and advice much appreciated! This episode has already cost more than £4k and still isn't right - am I very worried...

Bjorn