gearbox oil leak

[Thorney]

bordseye said:

Seals are like bearings. they are standard industrial items made in a range of sizes and available from your bearing factor. If I need a seal for my Volvo boat engine I dont go to Volvo I go to Seals Direct.

For that matter I am puzzled why McLaren replace the whole gearbox if there is a leak during warranty. Its a ridiculous way of going about things. Understandable with electronics with surface mount components but gearboxes are basic engineering not exotic.

It probably worth noting that the actual fuilure isnt just a simple rubber seal but the pair of seals that work with the input shaft, these and/or the shaft wear prematurely at both ends which in effect lets oil seep through to a void, once that void fills up it leaks out of the tell tale hole. The repair/rebuild is a new shaft and new bearings and seals, about £1100 of parts so no quite just a rubber o ring (I wish )

[12pack]

Thanks for the detail. Were improvements made since the 12C?

[Thorney]

12pack said:

Thanks for the detail. Were improvements made since the 12C?

There are differences between different build numbers let alone models!

For the 12c, some had catch tanks, some did not, for the 650s they moved the breather to higher up the box but no catch tanks, they also state (they being Mclaren) that 'some breathing' is acceptable, the downside is that it collects on the under trays so makes it hard to tell where its coming from but oil from a breather is 'fine' breather from the tell tale is not.

[Ingenere]

bordseye said:

I'd certainly expect that on minor components like a power steering pump, but even today I am surprised they throw away a £27k gearbox for want of a £3 seal. But then I guess an awful lot of modern technicians arent mechanics in the old school and only know how to replace full units.

The difficult bits about a twin clutch box arent the oily bits but the controlling electronics.

Anyway, none of this answers my question which is how common is the gearbox oil leak. Is it like Porker bore scoring? Or is it a pretty infrequent problem that was tackled by the time the 5 series came out?

Edited by bordseye on Friday 1st February 20:33

The problem is an infrequent issue. The complainers are all on the web. The vast majority of cars are just driven and enjoyed, but nobody hears about.

The aftermarket has figured a solution for about $1.