Rick (joycesjag), Wayne (cjd777), and I did a drain-and-fill on my 2005 S-Type's ZF in early November last year using Mercon SP. We did not drop the pan, just pulled the drain plug, so only a bit less than 5 quarts of the original Lifeguard 6 drained out (at just over 85,000 miles). I decided then and there that if I was happy with the fresh Mercon SP's performance during the months ahead, we would do one final drain-and-fill around the same time in 2015....

Almost a year has passed (as has about 6,500 miles) and the three of us are scheduled to do another drain-and-fill using Mercon SP on October 27th (again, no pan drop). My S-Type ZF's performance has been exemplary since last year's drain-and-fill, the upcoming ZF service will ensure that the majority of ATF circulating throughout my system is Mercon SP, and I hope this is the last time we have to touch my ZF for the duration of its time remaining in our stable....

 

If it had been a weekend I'd have volunteered to come and pass the spanners. (and a beer or two)

 

It’s been 4 months and 10,000 miles since properly servicing the transmission with MERCON SP (180,000 total miles on tranny). I have no problems to report.

The shift to fifth gear, which for years has been accompanied with a little nudge (it was a “slip & thump” with the RedLine fluid), actually seems to be a bit smoother since my 5,000 mile report. Hmmm, ….. I’ll have to keep an eye on that.

As expected, that slight morning RPM surging when in 5th/6th gear while level or on a slight up grade, has become a tiny bit more noticeable with the onset of cooler mornings. However, it is still WAAAAYYYYY better than it had been before and to tell the truth, an uninitiated driver might not even notice it.

So MERCON still gets two thumbs “and” two big-toes UP!

 

Me tooo..while I only have about 1K miles since the change to Mercon SP my squawk issue has completely stopped.

 

Yep, I agree that Mercon SP is the absolute way to go for all 6HP26 drain-and-fills. I have no qualms recommending it....

 

All HAIL Mercon SP, OK to spend the extra $ saved on refreshments!!!

 

I forgot to update this thread after changing mine out and using Mercon SP. I did a flush using the cooler lines since I had to repair the leak from them. My worsening shifts and gearbox faults seemed to stem from the low fluid condition from my leak.

Similar experience as the OP. 2-1 jerk is gone. Shifts are now super smooth. I have had a slipping 3-4 shift during warmup and that is close to gone now. Perfectly fine when the car is at operating temp. I'm thinking a trans reflash wouldn't be a bad idea, but I think I may wait and see what the adaptive shift feature does on its own.

 

Glad to see that you've joined the growing list of happy Mercon SP ATF users for the ZF 6HP26 unit. Keep us posted on your continuing performance improvements....

 

Ditto this Mercon SP is about $7qt from the auto parts here...

 

Yep, that's why I bought it. It still seems rare here and there was just enough stock between two O'Reilly stores for a complete flush. I'm not sure if I will be able to get more locally when I drain and fill with the pan swap, but I'm planning to give that another year or two before I deem that necessary.

 

You can purchase Mercon SP at any Ford dealership parts department for that same price range (about $7 per quart)....

 

I figured as much. My problem was that I was sourcing fluid on a Sunday.

 

Just did all this research on ATF/filter change on the 6HP26 in a KIA Borrego. Same transmission as the '03-'06 XJ/XK and the same as a few hundred thousand Ford vehicles. Ford builds this transmission under license from ZF in the US. Ford uses the Mercon SP in their transmissions. Ford's service recommendation is to change the fluid and filter at 150k miles.

ZF's formal, published recommendation if for fluid change at 50k to 75k miles for 'extreme' service. 'Extreme' is not defined. My Borrego never does anything extreme.

With all that info in hand I stopped by the local Ford store and asked for a price for a drain and refill with the Mercon SP on my Borrego at 100k miles. While bewildered, they said $50 labor, $5 shop charge, $45 for 6 quarts of the Mercon SP, $103 with tax for a 60% fluid change that was done by a Ford factory trained transmission specialist.

A thousand miles later the transmission shifts as perfectly as it has always. I am going to change the 6 quarts again shortly and that should be an effectively 85% fluid change for a total cost of $206. Best deal around and done well before the recommended interval.

Excuse me but I am not going to put a car on 4 jack stands and work under it for the $55 labor charge or even the $110 for doing it twice.

 

Thanks TestPoint. Good info. $100 bucks at a dealer is a sweet deal. I have access to a lift, so the inconvenience is minor, and I don't trust anyone else to correctly establish the fluid level.


Hello All,

This is the 20,000 mile / 10 month update on the MERCON SP6HP26 servicing. Performance has surprisinglycontinued to improve beyond the 10,000 mile report. The remaining slight "race anddump" upshift into 5th gear is completely gone now and none of the previouslyrectified anomalies have returned. All upshiftsare almost buttery smooth and downshifts (other than kick-downs) are imperceptible. Kick-downs remain very predictable and effective. For passing, I usually slip the J-Gate overinto 5th and let the transmission kick-down to 4th. This is very effective - from a 60 mph start,I'm doing about 90mph by the time the pass is complete.

The only transmission anomalies that remain are aslightly aggressive upshift to 2nd when pulling away slowly from a stop (not in Sport Mode)and the well documented morning surging which is just barely noticeable duringwinter temperatures.

Again: I cannot say whether it has been the MERCON fluiditself that has been responsible for such great improvements, or that it was justmaking sure the fluid level was precisely established, or a combination ofboth. However, the main point of thisthread was to determine the suitability of the oh-so-much-cheaper MERCON SP foruse in our 6HP26s. To that end, it hasbeen a resounding success!

I also cannot say for certain that the previouslyinstalled Red Line D6 fluid was the cause of so many of the anomalies that followedits introduction or that the shop botched establishing the correct fluid level. D6 is listed by Redline as a suitable substitutefor MERCON SP, but I won't ever use it again.

Enjoy your transmissions again folks (and sleep better at night - lol). Switch to MERCON SP and use the other $200+ for booze!

 

I questioned the Ford tech about the fill procedure and he knew exactly how it is done regarding shifting through the gears and the fill temperature. The Ford version of the 6HP26 has a vertical fill port and a very short dip stick to check the fluid level. That would seem ready to install an under hood dip stick if desired.

 

+1 for the Mercon SP. I had to do a drain and refill a few months ago, and decided to use Mercon SP from O'Reillys. No problems whatsoever.

 

My 2 cents: Had my 2004 XK8 with 52K miles serviced a year ago with Redline D6. Made a nice improvement in tranny performance. 3,000 miles later it's still perfect. As long as a fluid meets the Shell 1376.4 spec (which the Redline does), this stuff is all the same.

 

Bet the Redline was lots more than $0.02 higher than the $7.50 per quart Mercon SP.

 

Actually I was charged $5.60/liter 😀

 

That's good info George. Thanks.

As I suspected, the shop that put the D6 in screwed up getting the level right. "And" the Jaguar dealer I later had double check the level also missed the boat.

THIS is why I won't let anyone else service my transmission, .... or touch damn near ANYTHING else on my car. And as usual, once again I've become the best mechanic in the area to work on my car. I'm gonna drive a golf cart in my old age. Maybe I could find SOMEONE who could reliably work on THAT! (....sigh)