6 speed gearbox compatible with EW10A engine

[giochel]

My C5 X7 with engine EW10A and gearbox BE4 (5 speed manual) has gearbox problems, and the mechanics recommend the replacement of 1)input shaft bearing or entire gearbox, 2) most likely clutch and 3) possibly flywheel.

Is it feasible to mount another type of gearbox? The gearbox is about the only thing I hate about the car, because at 110-120 km/h it is at over 3000 rpm, and the engine noise becomes quite clear, while the engine has a enough torque bellow that. So I would like a 6th gear to keep the engine running under 3000 rpm.

If relevant, the gearbox does the following:
- noises: clatter when in neutral, but clutch not pressed
- sometimes may not fully engage gears 1, 3 and reverse, requiring a stronger push (or going through another gear first if the car is standing still).

[EDC5]

I think any EW engined gearbox should fit, maybe look at the 407 2.2 coupe. However, I believe there is an issue whereby the crusie control will no longer work as the expected speeds and real speeds will not match.

[giochel]

Thank you for the suggestion.

A few more questions:
- The transmission 407 coupe transmission would be 20MB06?
- What is likely to need custom work?
- Where do I get the instructions for doing a simple gearbox/clutch replacement? I couldn't find any repair manuals for C5 X7, only for older Citroens.