Vehicle: Vauxhall Astra GTC 2.0 SRI CDTI AUTO
REG: PJ64FTV

Issues with gearbox:
•After oil change, oil becomes black
•Starts slipping gears, but shifts and drives
•Oil changed again, same issues

How much will cost to replace the gearbox with a torque converter?
*Gearbox can be used or reconditioned*

Thank You
Regards