Hello everyone

I'm hoping someone has had the same symptoms as me.

Right my car is a 2wd sapphire Cosworth and at around 70 onwards I get a really nasty rumble, vibration coming through my car! Almost feels like the gearbox is going to fall out. It's rumbles through the gearstick and all over the car to be fair. Getting to the point I don't enjoy driving it anymore.

What I've done so far is refurbished all my wheels, new tyres and balanced. I have had the gearbox re-built and the propshaft doughnut changed and checked. Plus a good Standard gearbox mount replaced.

My next point of call is the driveshafts and diff

I hope someone has had this and can tell me what it is
Thanks