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Richard, Jaguar Technician
Category: Jaguar
Satisfied Customers: 15307
Experience:  12 years at a Ford/Lincoln Mercury and Jaguar dealer as technician and shop foreman.
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Jaguar S-Type: Dear Jaguar Mechanic, My 2003 Jaguar S-Type

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Dear Jaguar Mechanic,

My 2003 Jaguar S-Type has 49,987 miles on it. I purchased it used Feb, 2012 with 40,300 miles. When moving very slowly and then giving it a little more gas, the car jerks into gear. If I make a complete stop and then start up, no jerking. It also jerks at about 52-55mph. However, it does not always do that. I should also let you know that there is no jerking into gear if I engage the standard shifting and shift the car into 5th gear myself at about 52 mph. Do you know what causes the jerking into gear and what can be done about it? Thank you! Kelly

Hello and welcome to


DId the Jag mechanic clear the TCM and reflash it with a Jag tool? Was this done at a dealer? Did they check the fluid level and condition?

Customer: replied 4 years ago.

Hi Richard,


My final bill states "transmission adaptations out of calibration. Recalibrated the transmission shift adaptations per Jaguar specifications following TSB JTB00071 and test drove to verify repair.


What fluid level and condition? The transmission fluid? A complete inspection was done to determine mechanical or other issues. The Jag dealer told me all fluids had been checked.


Does that help?




Yes that is exactly what I was looking for. Unfortunately if the poor shifting is not resolved after performing this reflash then the TCM itself may need to be replaced. The TCM is actually part of the valve block inside the unit.
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Customer: replied 4 years ago.

Thank you, Richard! What is the average I would pay to replace the TCM?



Customer: replied 4 years ago.

Oh, and Richard, what is the difference between replacing the TCM and/or replacing the torque converter to solve this issue? Do you do one first and then see if you need the other or does replacing the TCM take care of replacing the torque converter at the same time?


Thanks so much!

The TCM/valve body and the torque converter are two separate parts. If you only had the surge problem than I say the torque converter will need to be replaced but the jerking and hard shifting could be the TCM. The problem is oh repairs can be costly due to the parts and for close to the same price you can have your unit rebuilt or replaced.
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