Hi im guessing from when you say it wont let you in,you mean it wont communicate with the ECU?
If this is the case i would first check all the wiring make a wire has,nt been broken in the fitting process.
Secondly the most common cause for this is that the ECU has failed.
Did you jump start the car after fitting the second hand gearbox?
This is a common mistake people make,as when you jump start the car the whole system gets a massive power surge which blows the ECU.
Richard
rbtrans@hotmail.com
Richard
January 2008