Flexible drive shafts and prop shafts!
That's the answer, although how do you get there?
Didn't Red Bull use flexible drive shafts as a firm of traction control? They then are the small amount of mechanical give needed for the metal work.
Or what about a "girdle" like the one for the sump and a custom shaft, might be more expensive than the custom casing support Andrew posted.
The answer realistically is mechanical sympathy...
You can spend thousands of pounds making the gearbox a bit stronger but its only as strong as the weakest point... in this case its the casting...
There are already established mods to 'strengthen' the box and as it appears the transfer box... there is of course associated cost to this and no guarantee that they will prevent the demise of the gearbox...
This is evidenced by Stacey who still managed to strip gears and bend the forks on his gearbox despite having all the available upgrades applied... granted he uses his car for drag racing but that just highlights the root cause...
02M gearboxes are relatively cheap to buy but decent ones a bit thin on the ground... with no launching and a few select modifications then there is no reason why the drive train won't survive a relatively long time but I am not really prepared to throw money at something that is essentially consumable
It turns a £100 repair into a potential £400 repair without 4 times the longevity...
Another avenue to explore will be the newer 02Q boxes... there are a few things to over come before this is viable though... the boxes themselves are essentially 02M internally so not really much stronger but they are more plentiful and lower mileage...
They don't however always have the speedo drive as later cars took speed from the ABS unit rather than the speedo drive... there is a possible solution for this as the IECU sees speed from the ABS... in discussion with Brian over this it should be possible that a firmware upgrade could enable a feature to emulate the signal from the speedo drive so that you can use both 02M and 02Q type boxes...
The other issue is that the 02Q version of the transfer box is 'longer'... this requires a shorter driveshaft to allow it to work... I don't recall the exact details (discovered this while putting Alex from DTA's car together as he had an SQS box built from an 02Q) but Alex ended up getting a custom shaft made...
We did try a few standard ones and there may well be a shaft thats a bolt on (Mk5 and above geometry is different enough that a std shaft won't necessarily work) but Alex got a custom shaft made in the end which is also an option but only if 02Q is made a viable option through the IECU...
If there was a way to build a box that you could be sure would last then great but unfortunately getting one even close would cost more money than I care to spend...
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