The small Volvo's automatic transmission is sensitive to oil cleanliness. If gear shifts feel jerky or the oil is black, it is time to perform a flush and oil change.

Oil type: Check your owner's manual (usually JWS 3309 or Dexron III depending on model year/transmission type). Quantity: Plan for at least 10–12 liters of oil so you can flush the system clean. Tools: 12 mm transparent hose (approximately 2–3 meters), measuring container for old oil, funnels (preferably long-necked or multiple nested funnels).

1. Finding the return line The transmission oil cooler hoses are located under the car, driver's side above the underbody protection. Slightly open the underbody protection on the driver's side. Return line: You identify the correct line by the sharp curve it makes upward and going to the transmission valve body (upward). This is the line to disconnect for circulation. 2. Removing old oil and initial fill Open the transmission drain plug and let the oil drain into a measuring container (approximately 2–3 liters comes out). Install the drain plug (with a new gasket). Add exactly the same amount of new oil from the fill tube (dipstick hole) that came out. Tip: The fill tube is in a tight location. Use multiple nested funnels or a funnel with an extension hose to reach it easily. 3. Circulation (flushing) Disconnect the return line from step 1 and attach a 12 mm transparent hose to its end. Direct the hose into a container you can see from the driver's seat (for example, next to the door). Start the engine. Let the oil flow into the container until approximately 2 liters has been collected. Turn off the engine immediately when 2 liters is full or when air bubbles start appearing in the hose. Add 2 liters of fresh oil from the fill tube. Repeat steps 2–4 until the oil flowing through the hose is bright red and clean. 4. Finishing and level check Reconnect the return line to the transmission. Start the car and slowly move the shift selector through all positions (P-R-N-D-4-3-L). Check the oil level from the dipstick with the engine running: Cold: The level should be in the "Cold" range. Warm: Drive the car to warm it up properly (approximately 15–20 km) and verify the level is in the "Hot" range.

Never run dry: Never let the pump run dry for long periods. 2 liters is a safe maximum amount to drain at one time. Cleanliness: Automatic transmissions are extremely sensitive to dirt. Make sure sand or debris does not enter the fill tube along with the funnel. Level gauge: Remember that oil expands when heated. Do not fill to the top of the "Hot" range while the oil is cold.

If the transmission has not been serviced for a long time, it is worth checking the transmission breather at the same time and cleaning it so that pressure does not bulge the seals out.