- 2 Min Read
- By: Jay Boucher
Volvo 240, 740, 940 Transmission Flush DIY
With proper care, the automatic transmissions for rear wheel drive Volvos will last as long as the redblock engines they're attached to. Proper care means a flush of the transmission fluid about every 30k miles. This is a very simple procedure and can be done for little more than the cost of the fluid.
Fresh transmission fluid is a beautiful, but toxic, translucent red, the color and consistency of cherry flavor cough syrup. If it looks like a 3 day old Starbucks latte then there's something wrong.
The AW70 series transmissions on the Volvo 240, Volvo 740 and Volvo 940 models from 1982-1997. While there is some debate about doing a full versus a partial flush, if you've been up-to-date on your maintenance schedule it's a good idea to do a full flush. Here's how:
What you'll need
- 6-8 quarts automatic transmission fluid (ATF), Dexron III/Mercon (label should say it is compatible with Dexron II D/E)
- 15mm open end wrench, preferably flare nut wrench
- Clean funnel
- 3/8" diameter clear plastic tubing, about 3 feet long
- 2x gallon milk containers
What you do
Your car should be parked on a level surface and the engine should be off and cool. You'll find the fitting for the ATF return line at the top left of the radiator. Disconnect it with the 15mm wrench and move it slightly to the side. Connect the plastic tubing to the radiator fitting and clamp on if needed. The fitting should be tight so as not to allow any leaks.
Place the other end of the drain tube into one of the milk jugs. It can help to mark the jug at one quart increments so that you can keep the same amount going in as coming out. Pull out the transmission dip stick, located in the back right of the engine compartment and place to the side. Insert the funnel into the dipstick tube.
Using this technique you will be pouring in fresh fluid while simultaneously draining the old. Start the engine. The flow of the ATF is slow enough that you'll be able to start the car and get back to the drain before any fluid has hit the jug. As the jug starts to fill begin pouring clean fluid into the funnel. You're aiming to have an equal match of fluid in to fluid out. In other words, by the time the gallon jug is half full you should have poured in 2 quarts of ATF. Keep it going until you've drained and poured in 6-8 quarts, then shut off the engine.
Pull out the funnel, wipe the dip stick with a lint-free towel and check the fluid level. One side of the stick shows cold temperature and the other shows hot. Since the car hasn't been fully warmed up you'll be checking the cool side. If the fluid is above the MAX mark you'll need to start the engine and drain a little more fluid. It's important not to overfill.
I've found it best to have the fluid just barely reach the MIN/cold mark of the dip stick right after flushing. This indicates there's enough fluid to run smoothly and I can add more later once the line is reconnected and the engine warmed up.
Reconnect the ATF return line and turn the car on. Drive or let the car idle for about 30 minutes to warm it up, then shut down and check the fluid again. This time you'll be checking the warm side of the dipstick. The difference between the MIN and MAX indicators is 1/2 quart so fill accordingly.
Dispose of the old fluid at an appropriate facility and you're done. Enjoy smooth shifting for many more miles.
Jay Boucher is a weekend DIY mechanic who loves station wagons and redblock Volvos. When he’s not scraping his knuckles under his 1992 Volvo 245, he’s working as a freelance illustrator and interactive designer in northern NJ. Jay’s portfolio is at jayboucher.com and he blogs at myblackbrick.com.