I supply overdrive only parts. Your on your own with the trans.

To service OD for current problem you will need:

Trans adapter to OD gasket; Actuating piston O-rings. These are part of a kit I put together that contains those plus: the gaskets for the solenoid, solenoid adjustment cover, and the filter cover; O-rings for the solenoid operating lever and the speedometer pinion housing; and the rear shaft seal. Just over $28 mailed to your door.

Keep in mind that the O-ring for the solenoid operating lever is more than a PITA to change. Depending upon year and month manufactured, the shaft is located by a blind pin which must be drilled out to remove the lever to change the O-ring. Then the pin must be replaced. A test of ones capability to hold a drill on pin center and not break the bit in the process. You will have more questions later so I'll save the details.

What to look for preventive while the whole sheebang is out...I'd change the 4th gear switch for a new one just because it is a real pain to get at with the tranny in place. For $25 or so from the dealer, it is well worth it in time saved if(when) it fails later. AND examine the wires and terminals that connect to the switch.

Tranny parts and gaskets are dealer items. If your local dealer does not have the savy or gumption to look it all up, I have a really good and friendly Volvo Parts manager that can generate correct part numbers almost out of thin air.

Duane