Good fellas , how is it going !?
I just bought a beautiful Stype 2005 , 4.2 V8 , 94500 miles on it . I did a quick test drive nothing to worry about .
So when I took it for a long drive going back home, I felt some bumps while changing gears , sometimes between 1-2 , 3-2 , like the torque goe down between gears while upshifting , and I tried a kickdown , it takes like 2 seconds to lauch it , and the gearbox gives a huge bump while downshifting .
I had a bmw e65 30d with the same transmission zf6hp26 , it was so smooth , even when go on kick down nothing bad happen !
I took the jag to a local AAMCO to make an oil change for both engine and transmission . He offered to rebuild the transmission and he canno't make the oil change for it , he said that he is afraid to do it , it could make the things worse . And he focused on rebuiding the trans and offered me financing and all that stuff. I asked him to clear the ECU and TCM and give it a try again maybe it would fix the problem and then we change the oil and filters , he didn't accept to do that !
I mean I know that smtg is wrong with my transmission, but I felt like the guy wanted to sell me something that I don't need based on my lake of informations and experience.
after diagnostic , we had this code number : PO829 , saying slip between gears 5-6 . But I don't have any problem on that level , the only bumps I feel are on the first second and third gear .
what do you suggest guys ? Help me please !

 

I would start with an ATF drain-and-fill using Mercon SP (available at any Ford dealership usually for less than $7 per quart). Only about half of the original ATF will drain out of your system (5 quarts or so), so put another 1,000 or so miles on the car after the drain-and-fill to determine if your transmission shifts have significantly improved. If they have, do one more ATF drain-and-fill to get your Mercon SP content up to between 85% and 90% and call it a day....

Make certain you follow the correct ZF 6HP26 drain-and-fill procedure to the letter. Search for it here on this forum and you will find excellent step-by-step instructions....



I would also check the age and condition of the battery. Low or dying batteries cause many issues in these cars, including faulty transmission behavior....

 

Since you just bought the car you might want to perform a 'CLEAR ADAPTATIONS' from the TCM and make sure the fluid level is correct.

This will require dealer level scan tool.

You can then drive the car (without 'sport-mode') to allow the TCM to 're-learn' shift patterns.

You might want to avoid the AAMCO shop, sounds like they are in over their head if they cannot drain/fill a gearbox.

bob

 

That's what I did this morning, I took off the negative cable for about an hour , and put it back , the ecu was cleared since I losed the seats memory , windows and radio too . I reset all that stuff and turn on the engine , hit the road, and to be honnest , shifting gears is a lot better now . I'm driving like an old man and I read that I should do that for about 300 miles so that the TCM could have an Idea about my shifting patterns .
Hope that will fix the problem . If so , do you recommand that after 300 miles , I change the fluid and filter ?

 

Thank you sir , but the transmission requires a ZF fluid , so do you think that mixing oils would not be a problem ? The AAMCO manager told me something about sunthetic vs mineral oil and I sould not mix them ! He told me after checking that my transmission had mineral oil on it . He charge 254 $ for mineral oil and 160 for synthetic . I didn't like the guy to be honest with you , I felt like he just want to push me to the path of rebuilding trans and he offered 2500 to do it . When I declined and I was taking my car off his garage, he came and offered 760$ for labor if I found an used tranny , and he gave me a business card of someone working in a junkyard lol . He said thag this guy is so honnest , don't buy from someone else. Ask for a lifetime warranty and he will charge you only an additional 200$ for that .

 

That doesn't clear the TCM.

 

The Mercon fluid referenced above is approved for our ZF transmissions. The AAMCO guy sounds like a crook or an idiot or both. Run away.

 

So how can I do that ? Shifting gears really improved ! Still a little bump between 1-2 gears though , but no more than that .

 

I found those , which one is better ?

 

Did you read my post???

Clear Adaptations "This will require dealer level scan tool."

The TCM adaptations are stored in the module. Disconnecting the battery will NOT clear the adaptations. Rewriting some of the software in the module will clear the bad habits that the module has learned over time if that is what happened.

Many things cause the TCM to have faulty shift patterns.

bob

 

got you ✌

 

You may want to find a reputable local independent Jag garage and have them look at your trans.

 

I saw a lot of videos about a transmission additif called LUCAS STOP SLIP . Should I use that while changing my oil ? Did someone use it here guys ?

 

NO!

Or any other additive. This applies to the entire vehicle.

 

share your concerns with me please ?

 

This transmission needs a very precise fluid with exactly the right combination of additives in the correct amount. It's proven to work perfectly- right out of the bottle.

Any additive is more than likely to upset this balance in a negative way.

Please share why you feel the need to re-engineer stuff.

 

so which one of those oils that I shared below, you think will be perfect for my tranny without the need to add an additive in order to get better shifting ?

 

Um, Except the power steering additive I think .
Worked a charm on mine . Combating a common fault .

 

Two of us have already answered this question.

 

True, but that was a factory endorsed additive to bring fluid up to snuff and equal with the later type fluid.

Very different than some guy who's read too many hot rod magazines sponsored by snake oil vendors.