Hello guys, Please i have the wrong transmission oil in my gearbox for over 3 months now. I am looking at switching to the Toyota T-IV. What's the best way to do a switch without causing damage. I have 140,000 on the clock.

 

By "wrong" transmission fluid it sounds like you want to run JWS 3309 spec'd fluid (aka Aisin 1161540 which is Volvo's part number). Curious what's in there now that you would be saying you have the wrong fluid. There's two ways to go about this: 1) you can do a true fluid flush which is done by opening the line going to the transmission cooler and run a hose to a bucket. start the car and let the transmission pump out about 2 quarts, then stop the car. Add two new quarts. Repeat until you've done about 10 or quarts - you should be seeing very clear fluid coming out at this point. Reattach the hose and fill the car to the cold fluid line. start the car up run for a minute, recheck the level. Now take the car out for an easy drive to fully warm up the transmission (could take 15 minutes). Now recheck your fluid level to see if its measuring at the hot level on the dip stick. adjust as needed. Option 2) drain from the bottom - you should get about 3-4 quarts out. Refill with the same amount. Start the car up to let the new fluid circulate. Stop, drain again and refill 2x more (total of 3). This will take about 12 quarts either way. Assuming you have some Dex3/Mercon in there, its not really all that different - just doesn't have the identical friction coifficient as JWS. The 3X drain fill will get you to 80% fresh, the flush may get you to 90%... Both should be good for another 50-100K miles. Note Toyota also uses the Aisin transmissions and T-IV is the same as JWS 3309 spec fluid.

 

Thanks for the response. I currently have a Dexron III in my transmission and I was told it would cause problems for my transmission. And I have 140,000 on the clock. Can I still go ahead with the drain and refill method as they are different oils?