Well, not flushing, exactly. I'm going to drain the fluid, change the pan and filter, and then refill it with Mercon SP or Redline D6. The Mercon SP is specified for the 6hp26's used in Fords and the Redline says it's compatible with 6hp26's. I'd like to get as much of the old fluid out as possible, including the fluid in the torque converter. It's my understanding that there are about 7 quarts of fluid in the main part of the transmission and another 3 in the torque converter.

I'm thinking I have two options. The first would be to drain the fluid (7 quarts) refill it, drive it around some to circulate all of the fluid, including the fluid that's in the torque converter, then drain it and refill it again. I'd be leaving 30% of the fluid during each drain/fill, and 0.3 times 0.3 equals 0.09, which means in the end I'd have approximately 91% new fluid and 9% old fluid.

The second option is to drain the fluid, change the pan, and then start pumping in new fluid with a garden sprayer filled with 2.5 gallons (10 quarts) of fluid. I'd pump in new fluid as the old fluid (from the torque converter?) drained out. I might even have a few extra quarts handy to pump in just to make sure I got as much of the old stuff out as possible.

Soooo... (here's the important part) which method is going to result in getting the most new fluid into the transmission? I could even do the first method a third time, which would result in about 97% of the fluid getting replaced. It would also cost me an extra $35 in fluid, which really isn't a big deal in the grand scheme of things. I just want to get as much of the old fluid out as possible.

One last thing... When I got the car I noticed that under hard acceleration the transmission would "chirp" or "bark". There was a TSB that addressed the the issue, and I bought a $50 bottle of additive that fixed the problem. Am I going to have to buy a whole new bottle of additive?

 

Pretty much. The formulation of your replacement fluid probably does not include the additive. But then, is barking such a bad thing under hard use? It causes driveline shock, but it also means that your tranny is shifting with the least amount of slippage.

There is another method of changing your fluid. It involves draining from the cooler return line at the transmission. The fluid pumps through the tranny, converter, cooler and then the drain bottle. It's in the faq somewhere.

 

When I changed the fluid on my 2003 S-Type 4.2 which has the same 6HP26 (just a basic drain and fill, and used Castrol Import Multi Vehicle, BTW), the chirp diappeared. I actually bought the additive but did not need to use it.

 

Hi Rev Sam,

Thanks for all the work you do. Have been reading up on transmissions. But since I have a 2000 XK8 does all your good info apply to my transmission? If not is there a thread that covers the transmission in the 2000 XK8?

EZDriver