Cold transmission won't go into overdrive??

Hi all I am buying a 1998 XJ, the owner says that the overdrive will only go into overdrive once it warms up for about 10 minutes. He said he opened the bottom of the tranny and everything looked clean. I figured I would pick your brains about what the problem could be. Any help would be appreciated. The jeep is clean otherwise with no rust and in good condition. Thanks guys.

A failing overdrive or torque convertor solenoid could cause a no overdrive condition. It should 4hrow a check engine light though. If the light is on, have the trouble code retrieved at a local parts store and start investigating that circuit.

Thanks man I appreciate it.

You're looking for a P0743, lockup solenoid code. You can drop the pan and ohm check the solenoids or pull the TCM connector and underhood harness and ohm check them that way. Spec is 12-15 ohms. I was having the opposite problem from you in that mine failed only when warm. I pulled it when hot and checked and it was right at 15 ohms. I replaced all 3 solenoids ($65) and haven't had any problems in a year.