To Flush or not to Flush

To flush or not to flush?

I have a 2000 Ford Expedition. It has been a great problem free truck. I am the second owner of it. I bought it at about 50,000 miles. It currently has 94,000 miles. To my knowledge the transmission has never been flushed. During one of my disappointing Dallas Cowboys games I decided to go tinker with the cars and check the fluids. It is a maroon instead of the typical bright red. The dealership, along with other shops, insist I flush it and change the filter. Being the warrior I am I changed the filter myself. I then added 6 quarts of mercon V fluid. I have heard, and read horror stories, of flushing a transmission for possibly the first time with high mileage on it. should I take it and have it flushed or let it be? There are no slipping, shifting, grinding or any problems with the transmission at this time.

I would leave things alone and then do another filter change/pan drop in 25K miles or so. You are probably diluting the fluid at a 50% rate without flushing.

I would also run the car about 500 miles and reinspect the color. If it still looks maroon, then do another change out at say 10K miles.

On the other hand, my Ford trucks get a fluid exchange with filter change out and I have had no issues with either of them. If you got a major color improvement through what you did, I would leave it alone and do the maintenance more frequently.

I would not have it power flushed. I would do nothing more than you’ve already done.

There’s still 10 quarts of the old oxidized fluid in the transmission. So that 6 quarts didn’t improve the condition of the old fluid. All that was done was the new fluid was contaminated with the old oxidized fluid. Not much good.

If you’ve already replaced the filter then have the tranny fluid exchange done. This will replace all the oxidized tranny fluid and provide the proper lubrication for proper tranny operation.


Flushing a transmission will never be a problem if the pan is dropped and cleaned first along with changing the filter.

If you decide to change the fluid again you might look the torque converter over. Some Fords have a drain plug on the torque converter so that would get rid of most of the remaining fluid. Whether your particular model has a drain plug I don’t know but if it does there will be a small dust cover on the bottom of the trans that must be removed. The torque converter can be rotated by hand until the drain appears.

I would recommend changing the fluid and cleaning the filter a lot more often than you have.

Second I would ignore all those stories bout the transmission that failed shortly after changing or replacing the fluid. Remember that few people bother the change the fluid until they notice a problem, they then do the service and a month later the transmission fails. They blame the fluid change, when in fact they should be putting the blame on the three or four fluid changes it should have had, but no one did.

Good Luck

I suppose this is nit picky, Tester. But, it does indeed “improve” the condition of the fluid to put 6 new quarts in a 16 quart system. The problem is, it doesn’t improve it enough. That’s why it needs to be done several times.

My 2002 Sienna has a drain plug, which I think is wonderful. I replace out three quarts every time I think of it, and am back in the States. At 173,000 miles it still shifts smoothly.