Very noisy engine at 60mph+

[RichardW]

If it was there before the box was changed, then it's nothing to do with that. It could be the engine, but given that it appears to be road speed related, I doubt it. I suspect it's drive train related; either a wheel bearing, driveshaft, tyre or brakes. No need to spend any money on computer diagnosis - take it to any half decent garage, get them to test drive it, and see what they think. If you could post a video of the noise we'd have a better idea...

[GiveMeABreak]

Given that the last ‘decent’ garage he went to changed the whole transmission, without fixing the problem (and at considerable cost), a proper diagnosis surely has to be the way forward.

A diagnostic is basic advice that really should be first on the list for something like this - unless one has unlimited funds of course. It is still possible it is ECU related - do we know if the original ECU was replaced or transplanted? If I had your VIN I could have a look for some symptoms.....