I’ve bowed to defeat in the Porsche Cayenne transmission failure saga and am sending the car for a gearbox rebuild. What should have been a simple Cayenne valve body rebuild and refit is now a transmission-out overhaul costing thousands of pounds.

The last straw came on Saturday, when I spent all day checking through the metres of copper linking my Cayenne ECUs with the gearbox internals. All I found was a soaking wet floor, courtesy of the leaky rear washer jet pipe that pours screenwash into the car when it works its way loose. The leaking water then floods wiring looms and everything else it can find, including the Cayenne’s main ECU. Some of the damage it does:

Pulling all the transmission wiring back into the Cayenne, I could find no broken cables and no obvious problems. I’ve already double checked everything the boys have done on installing a genuine Porsche valve body/valve block costing over £1,000. The automatic transmission shop will run a diagnostic on the transmission when it gets to them tomorrow, but there is some form for these Porsche Cayenne Aisin gearboxes to jam their clutch packs, so I’m not mega optimistic.

As an experiment in running a Porche Cayenne daily driver, the last six months have taught me not to recommend these cars. I enjoy driving my Cayenne V8 and it is just about affordable on LPG, so I will stick with it as a means to recoup some of the money I’ve poured into it, but I would not advise others to follow my lead. I’m not saying don’t buy a Cayenne, just don’t ask me to tell you it makes sense.

I almost bought a Volvo XC90, but ended up in the Cayenne. Even as a Porsche enthusiast, it’s a difficult decision to defend when you look at the full cost of ownership over my six months to date compared to something more reliable. The recent bills are a bit raw at the minute: some fresh V8 burble will ease that pain.