Hi,
I recently purchased a 2002 TJ Magna that needed a bit of work.So we have rebuilt the motor and thought the Transmission was fine so started it up and it was driving fine had a 5 second delay from N to D but wasn't worried.So a little while later after checking a few things on the motor went to put the car in D and nothing no go can reverse but not drive forward.Only seems to be happening when car has gotten hot.Checked fluid levels they all seem to be fine now but it is still happening.....Any ideas greatly appreciated

Try the Tech Torque forum in here. There is a sticky Thread called "Workshop Manuals" - if the links are still working, you can download Gen Mitsubishi Workshop manuals as PDF files.

Assuming you can download the PDF for TH-TJ and later models, look in Chapter 23 for Auto Transmission. There is a detailed Trouble-Shooting section, which lists a variety of possible causes for both the long delay from N to D, as well as the loss of drive in forward gears.

Auto Trans is pretty complex, its likely you need professional intervention, but have a read of the Troubleshooting and follow directions of what it suggests...... Good Luck.