Hello, this problem has really got me stumped, so any help appreciated.
I have a 2006 C70 2.5 T5 with the M66 six speed transmission. When accelerating moderately hard up a hill, I heard a loud bang and lost all transmission drive. I managed to roll back into a parking space and the engine was still running fine. The clutch felt like it had gone soft and even with the engine running and clutch up I could select different gears with various grinding noises depending on the gear chosen, but still no engaged drive. The following day whilst waiting for the tow-truck the car started up fine.
This is a project car and even with low miles had been driven hard and not well maintained by its previous owners. I had been going through various areas of the car and had just rebuilt the front suspension with new drive shafts and wheel-bearings as well.
The previous owner told me he had changed the clutch recently and when I removed the gearbox the clutch assembly looked new, but the DMF had a lot of play.
I bought a used M66 gearbox and compared the old and new boxes side by side, engaging each gear and turning the input shaft on both to make sure I had the same final drive ratio.
Oddly enough the original gearbox turned freely and I could see the splined output collars where the driveshafts engage turn as well.
Thinking that the problem was internal with the old gearbox I fitted the new used gearbox with a new clutch, slave cylinder, DMF, new bolts etc.
The box fitted up to the engine first time perfectly and bolted up with no fuss.
The clutch feels very light still when pressing on the pedal with the engine off.
I am waiting for a few new parts, so haven't started the engine.
The car is parked on a slope in-front of my garage and yesterday I put the car in 1st gear, gently released the hand-brake and took my foot off the brakes, expecting the car to roll forward a few inches before the transmission / engine compression would stop the car.
There was no engagement of the drive-train at all in any gear and the car just rolled forward.
I am completely stumped by this. With one wheel off the ground and the car in-gear, I can spin the wheel freely.
In case you are thinking, I haven't refitted the old box by accident! (which might be ok after all)
With all the work involved, you can imagine the frustration.
I will remove the starter motor and turn the engine over just to make sure the DMF and clutch assembly rotate as well.
My mind imagined a broken crankshaft where the DMF bolts up to, but I dismissed this as I was able to start the car the day after the incident.
The gear change selector cables appear to be fine and give the impression that I can engage each gear as I go through them one by one, but I will also manually try to engage the gears directly on the gearbox to see if that will allow an engaged drive.
The driveshafts are fine too.
When I fitted the clutch the pressure plate compressed as it should clamping the disc to the DMF.
Could the clutch be jammed open somehow?
I am completely stumped by this and just hope I don't have to take it all apart again.
You help and thoughts are greatly appreciated! Many thanks, Philippe