Clk 270cdi 55 plate auto gearbox sticking

[alf1956]

I have a 55 plate Clk 270 cdi with 130,000 miles, every now & then the gearbox will not change up into top gear & if i try to change it into "S" sport mode form the "C" mode on the switch adjacent to the gear change & it will not switch over to "S" mode but when the gearbox is working normally i can switch it from "C" to "S" mode wothout a problem. I have bought a gearbox dipstick & checked the level which seems to be fine. Anybody had this problem or got any ideas on it please?

 

[Steve@Avantgarde]

Sounds like a potential electro plate or solenoid on the electro plate.

I would get it on STAR and see what fault codes or what the adaptation data says.

 

[barnaclebill15]

One of the symptoms I had when my box stuck in low gear was no way to change from S to C, when it got on STAR it was the electro plate, STAR reading is the way to go.

 

[alf1956]

Today I was driving & the car would not change up into top gear so I tried a few experiments, I tried to manually change gear by knocking the gear lever over but it didn't change gear, then I tried to change the mode from C to S again no joy then moved the gear into neutral & then back into drive & it went straight into a low gear & would not change up at all so I pulled in & turned the car off & started it & drove off with it changing up & down the box no problems. I have had it not changing up & I have stopped & turned it off & started it again & it goes back to driving perfectly normal. I t will go for days without a problem then out of the blue it will not change up to top gear so I am wondering why when I turn it on & off it runs perfect so could it be electronic & when you turn it on & off it re-sets itself?

 

[malcolm E53 AMG]

Yes as above all the symptoms of the speed sensor on the gearbox electrical plate failing, STAR codes will confirm and circa £450 job inc parts & Labour.