I used my 05 S-Type for the after wifey (who normally drives the car), I notice a lurch at low rpm and low gears. I came to a light and felt a hard shift. I started to drive and the car did not shift gears and the transmission fault light came on (no red light). Took car right home at low speed and rpm. No leaks, looking for help or suggestions before taking car to dealer.

All help will really be welcomed.

 

Until the codes are checked we don't know. It could be something simple like low fluid level.

How many miles and has the transmission been serviced?
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Unknown, car has approx. 90,000 miles, I have had since March 2011 and have not had trans serviced. Car is not daily driver, may have only put 5000 miles on it since I have had it.

 

Check the battery is Ok as a first port of call. A failing battery is well known for throwing up all kinds of electrical problems.

Next on the list is the Gearbox electrical connector sleeve. Its worth checking that this is in fully and the connections are tight.

Other than those I'd suggest getting the codes read.