My 2005 XKR convertible (Nigel) now has 119,000 miles on it, but atheistically it is in very good condition. As the third owner, I have not had any engine issues other than some preventive maintenance items such as replacing the supercharger belt, supercharger idler pulley, the serpentine belt and regular oil changes. So, I have been very fortunate in that regard. Recently however, I have noted, when cold, the transmission seems to have some indecision about whether it should be in 4th or 5th gear, or 5th or 6th and very quickly changes from one gear to the other, back & forth. On the highway it works fine in 6th. The transmission fluid was changed at 97,500 miles in September of 2013.

Any ideas as to the cause of this? Should I have it fixed or just drive it? If it was to be "fixed", what would the estimated cost be?

Thanks for your input and suggestions.

Gerald Clark
Leawood, Kansas

What ATF was utilized during the 2013 transmission drain-and-fill? How many litres were drained and then refilled?

While your current ATF has less than 22,000 miles, it is 7.5 years old. All fluids break down over time and heat cycles. If it were my car, I would do another ATF drain-and-fill using Mercon SP. If that does not improve your shift quality, I would then consider having the ZF 6HP26 Adaptations Drive Cycle (see TSB JTB00145 for details) performed by a competent service provider....

You may also wish to speak with ZF Tech Support in Chicago, phone (800) 451-2595. Ask for Steve Jaffe or Joe Laubinger....

Jon89:
Sounds like great advice. I will proceed on that basis.
Thank you.
Gerald Clark

Gerald

+1 to Jon89. He knows his stuff, and your experiences sound like you've caught the problem early. Switching out the ATF transmission fluid actually should have been done in 2 stages as the Torque Converter holds alot of old fluid. So the process needs to be done 2x, the second time after being driven. Also maybe the ATF level is wrong, or you've developed a leak somewhere. Still attacking the ATF is the first thing to do and relatively inexpensive.

BTW Any reason you called your 2005 XKR "Nigel" ?

David:
More good advice and Bahrain!!
Background on "Nigel." I like to name my cars. One of my favored "British" names is Nigel.
However, at the shop where I had the refurbishing done when I acquired the car, upon arrival of
my Jaguar, they termed it the "Pension Plan!" I will be making an appointment with this same shop tomorrow morning.
Cheers,
Gerald Clark

Don't forget the basics, double check the rear tire pressure. A low tire (especially driver side) will relay incorrect road speed to the TCM and can cause erratic shifting. Road speed through the ABS reluctor ring is a lot more sensitive than you might think.

Next step, double check wheel bearings, again, especially in the back. Play in these bearings is not your friend. Many have spent a ton on new/rebuild this or that, when the root cause was bad bearings all along.

You cannot go wrong with a flush/refill of the fluid, MERCON SP is a great choice.

Once done, follow up with a reset of the adaptations. This is a software procedure instructing the driver to drive at certain speeds for some time. The "factory/dealer" SDD software does this most certainly, but some handheld devices claim to be able to as well.

fmertz:
Thank you for the "heads up" on the issues and suggestions you outlined. Your input is appreciated.
Gerald Clark

Jon89:
I proceed with an ATF change as you suggested and the transmisson has been working well since.
Thank you for the good advice!
Gerald L. Clark

Glad to be of assistance. Here's hoping that fresh ATF did indeed resolve your issues....