S tronic jerking

[Leighspain1975]

Hi All

Have a problem with the Dl501 stronic. When the car is in D from a standstill and I release the foot brake the car Jerks forwards. I also see the Rpm suddenly drop and pick up again.
It does this almost every time but seems to be worse the longer the car is stopped in D with the foot brake applied.

gearbox has always been serviced at the correct intervals.

also I’ve noticed that the gears keep changing from 6th to 7th at about 50 mph. It will stay in 7th but the second I touch the throttle it jumps back to 6th and back to 7th. I have to put the car in manual mode just so it holds gear for longer.

thanks for your help

 

[John Wr]

Hi. This is not a direct answer to your problem as I can only relate the circumstances of a recent problem I had with my S-Tronic.
My gearbox is at 102K miles, oil changes done at the correct intervals and the next change would be due in 9K miles and with no problems. Then driving recently gearbox hunted between 7th and 6th gear for no apparent reason. Within a few hundred yards DIS showed "Gearbox malfunction: you can continue driving(limited functionality)". Another 1/4 mlile DIS showed "Gearbox malfunction:no reverse gear (you can continue driving)". At this point I could feel the gearbox really jerking, so I decided to pull off the road into a very convenient layby. From here the car was recovered by flat bed to a main dealer.
The initial prognosis when the service manager tried to park the car was Mechatronic fault!!!
On a ramp the problem could easily be seen. The underside of the car around the left side of the gearbox and including one suspension arm was covered in oil. The filter housing had either become porous or had a hairline crack which allowed the oil to be lost. There had been no sign of any leaking whilst the car was parked at home, all surfaces were perfectly clean, so to me it had been a rapid oil loss. An inspection of the oil remaining in the gearbox did not show any swarf contamination.
A new filter housing and filter were fitted with fresh oil and the car is once again driving normally. A "cheap" result, but I am left wondering how many gearbox lives this has used up. Memo to others: a gearbox needs its full complement of oil to perform.

John