I am adding my own experience to the debate over drain and fill versus flushing a relatively "high mile" (debatable for sure) transmission. Here is my story.
My vehicle is a 2000 Volvo S40. It is equipped with a four-cylinder turbo engine and a 4-speed Aisin Warner transmission that originally spec'd Dex III fluid. This transmission is a little odd in that it has a factory external transmission cooler but no filter.
I purchase the vehicle in Aug 2007 with approximately 81,000 miles on it. Based on the dark red/slightly brown color to the fluid, I believe it was factory fill. Very soon after purchase, I added the, at the time, recommended dosage of Auto-Rx** to the transmission and drove it for 3,000 miles. At 84,000 miles, I did a cooler line flush with Redline D4. After the flush, there was no discernible difference in performance between the old fluid and the new, good or bad. My vehicle currently has 144,000 miles and I have not had any transmission issues whatsoever. In the intervening time, I have flushed it twice, once with Dex 6, and then shortly afterward went back to Redline D4. Again, no real difference in performance but for my own piece of mind, and really not based on anything other than brand preference, I am more comfortable with the Redline D4 in my car.
I just wanted to add my experience as there has not been a lot of long-term follow-ups from transmission flushes.
**Full Disclosure: I do not want to open up the Auto-Rx debate but just note that I did in fact use it. FWIW, when I flushed the trans fluid, the color had changed from dark red/slight brown to used engine oil black.
My vehicle is a 2000 Volvo S40. It is equipped with a four-cylinder turbo engine and a 4-speed Aisin Warner transmission that originally spec'd Dex III fluid. This transmission is a little odd in that it has a factory external transmission cooler but no filter.
I purchase the vehicle in Aug 2007 with approximately 81,000 miles on it. Based on the dark red/slightly brown color to the fluid, I believe it was factory fill. Very soon after purchase, I added the, at the time, recommended dosage of Auto-Rx** to the transmission and drove it for 3,000 miles. At 84,000 miles, I did a cooler line flush with Redline D4. After the flush, there was no discernible difference in performance between the old fluid and the new, good or bad. My vehicle currently has 144,000 miles and I have not had any transmission issues whatsoever. In the intervening time, I have flushed it twice, once with Dex 6, and then shortly afterward went back to Redline D4. Again, no real difference in performance but for my own piece of mind, and really not based on anything other than brand preference, I am more comfortable with the Redline D4 in my car.
I just wanted to add my experience as there has not been a lot of long-term follow-ups from transmission flushes.
**Full Disclosure: I do not want to open up the Auto-Rx debate but just note that I did in fact use it. FWIW, when I flushed the trans fluid, the color had changed from dark red/slight brown to used engine oil black.
