One more hint on removing the fill plug on the side of the transmission. I used a normal 8mm allen, but cut part of the short end off. Left about 3/4 of an inch. Then since the long end doesn't give you much leverage, I slip a large box end wrench over the long side of the allen for extra leverage. Works every time. The fill plug does sound like something has broke when it turns loose. Thanks to everyone for all you ideas. Looks like I am not the only one needing a fluid change and wanting to do it themselves.

Maybe the second one at least

Remember, the joy is that as the car gets more miles on it, the more often you'll be on your back draining/refilling the transmisison fluid .


I've drained/filled the fluid twice, and changed pans on my 03 S-Type. I can tell you that:


*A quick drain and replace will mean only 3 to 4 quarts come out when the vehicle is level. When you leave it dripping overnight and up on ramps, you get over 7 quarts.


*an 8mm long-handled allen wrench shaved down a bit will get that fill plug out without too much over-torquing -- lefty loosey.


*a less than $10 transfer pump from Harbor Freight works fine as long as you don't get overzealous in pumping and tip over the bottle of transmission fluid onto your garage floor...


*a pair of Rhino ramps and 3-ton jack stands AND a carpenter's level AND a cheap infrared thermometer have worked well for me so far


*the ONLY way to tell if you've added the correct amount of fluid is to keep the car level and keep the transmission at the proper temperature. The "you've got it right" indicator is a steady trickle of fluid out of that fill hole.


*I don't want to start a "my transmission fluid is better than yours" argument, but I'm hesitant to run Mercon SP in the ZF 6HP26. I did that after my old pan cracked less than a month after getting a local shop to replace the Lifeguard unicorn blood with new, freshly killed unicorn blood. I tried out the Mercon SP. My shifts seemed slower and my torque converter, admittedly one with a pre-existing delayed TCC lockup condition, really didn't like the Mercon SP's friction modifiers. Noticibly more surging when warm-up on cold starts around 40mph. Lubeguard red muted the surges until a paycheck or two later I could afford to replace the Mercon with Lifeguard 6 -- which is doing wonders though.

The Lifeguard6 has also comes down a lot in price. So at about $16/liter I used it. Still way better than the $50+ that it started out at!
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