CLK220 transmission not changing

[barnaclebill15]

For over 60k since I had a second hand box fitted all has been ok, had a few things to get done on Friday by my local indie including changing the ATF and filter.
On Thursday the transmission stuck in a high gear, noticed when pulling away from lights also it would not change on manual, stopped switched off and restarted all ok, when I dropped it off for service I mentioned what happened and they said probably needs the ATF changing which we are doing.
Picked it up at 5pm and heard the garage is on holiday for two weeks, drove home and just as I arrived it felt as if it was not changing.
Saturday it stuck in a high gear once but reset ok after switch off and on, today after about 30 miles with a couple of stops all ok got home but had forgotten something drove back out and was stuck in a low gear, stopped switched off restarted but still the same.
Can reverse ok go into park, stop and start but stays in a low gear 3000 rpm to reach 40 mph, tried to change mode from S to C but not changing that either.
Wonder if it's high temperature, oil not circulating the cooler as every time it's when I have covered a few miles before the problem starts, will leave it for a couple of hours and try it again.
This is worse than before I changed the box last time, at least then it would reset ok although it failed in neutral then

 

[Flyinspanner]

Maybe the speed sensor on the electro plate? Do you have an icarsoft or get it on STAR to diagnose faults.

Good luck with it.

 

[barnaclebill15]

Yes I suspect the electro plate but have no reader, There is a main dealer 3 miles away but don't know what they would charge for a STAR check, next indie is about 25 miles away.

 

[barnaclebill15]

update, left it all night and just tried it, still stuck in low gear, when you go from park to drive there is a lurch also when you go to reverse.
Just double checked and my local indie is closed, would be able to drive there in low gear on local roads and would prefer them to do the work as they have done all jobs in the past so will leave it on the drive for two weeks and hire the cheapest car, getting a little old now to get under cars and buying ramps and axle stands plus some extra tools would be nearly the cost of the hire car.

 

[rifiki]

Had similar problem with my W209 7g box at around 60k miles, new electroplate.

 

[barnaclebill15]

Driving round in a pink Fiat 500, changing it on Wednesday, just realised the lost comfort of the CLK and left foot paining from clutch operation.

 

[LostKiwi]

Driving round in a pink Fiat 500...

I'm sure its very fetching on you....!

 

[barnaclebill15]

Just a thought, if it's the speed sensor on the conductor plate can that just be changed or is it built in to the plate, looked at someone changing a plate on youtube and removing solenoids and replacing them on the new plate but did not mention speed sensor.
Update on the hire car, the guy in the hire place gave me a Seat Leon with a 7g auto when I returned the Fiat 500 after two days.

 

[LostKiwi]

The speed sensors are the yellow bits on this drawing:

They are not available separately. Solenoids are, sensors aren't.

 

[barnaclebill15]

Thanks for that, excellent graphics.

 

[barnaclebill15]

Got the result on STAR, it was the electro plate, they made time to fit a new one and just waiting to pick it up after the road test.