Transmission issue

[Chimp400]

Ive not driven it yet but the Transmission my Dads car has started to play up and just wondered where to start with it.
2004 C180K pretty sure its the 5 speed Auto transmission.
Fluid replaced last year and car is on 78000 miles, no shifting issues until now.
He said the shifts became irregular and clunky but also noticed the gear display on the dash clocks pixelating and flashing.
Will be having a look at it tomorrow and starting with a code read.
Any common issues to look out for on these?
Thanks

 

[DSM10000]

Ive not driven it yet but the Transmission my Dads car has started to play up and just wondered where to start with it.
2004 C180K pretty sure its the 5 speed Auto transmission.
Fluid replaced last year and car is on 78000 miles, no shifting issues until now.
He said the shifts became irregular and clunky but also noticed the gear display on the dash clocks pixelating and flashing.
Will be having a look at it tomorrow and starting with a code read.
Any common issues to look out for on these?
Thanks

First check is for a correct fluid level. This is usually done with the transmission at operating temperature after cycling through the gears and must be on level ground. There should be a dip stick for the transmission on the car which, as you say, is the 5 speed version. You may have to break a clip on the dipstick tube to be able to remove it. Replacements are cheap.

Check under the car for any sign of leakage, the large electrical plug is known to leak (cheap to replace the circa £25),the fluid can also track up the cables and get in to the transmission ECU and cause shift issues.

In addition, has any liquid been spilt over the selector mechanism?

 

[Chimp400]

No liquid spilt, where does the transmission ecu live?

 

[W1ghty]

You will need to buy an eBay dipstick to check the gearbox ATF level (722.6 gearbox dipstick on eBay )

 

[Chimp400]

I believe he already has one.

 

[DSM10000]

No liquid spilt, where does the transmission ecu live?

Passenger footwell I believe!

 

[DSM10000]

You will need to buy an eBay dipstick to check the gearbox ATF level (722.6 gearbox dipstick on eBay )

Good point. I thought it had one.

 

[W1ghty]

Good point. I thought it had one.

It was an optional extra (Unless the early CLK’s had one fitted , mine doesn’t )

 

[Chimp400]

Merc sell you a generic dipstick that you need to cut to length.
A bit of a pita to be honest, I've been through all this.

 

[DSM10000]

Merc sell you a generic dipstick that you need to cut to length.
A bit of a pita to be honest, I've been through all this.

A piece of curtain wire with markings would work!

 

[W1ghty]

Merc sell you a generic dipstick that you need to cut to length.
A bit of a pita to be honest, I've been through all this.

So you have a dipstick ?

 

[Chimp400]

So you have a dipstick ?

Not originally he bought one.

 

[W1ghty]

Not originally he bought one.

And the gearbox oil level was checked
on a flat surface ,
after a 20+ minute drive
with engine running ?

 

[Chimp400]

No need for a 20 minute drive but yes to the rest.

 

[DSM10000]

No need for a 20 minute drive but yes to the rest.

The gearbox fluid needs to be at 80 Deg C when the level is measured.

 

[KeithDee]

Failing all above could be conductor plate

 

[Chimp400]

Conductor plate looks fairly common and not too tricky to replace so will see what happens.

 

[Chimp400]

Good video here on the conductor plate.

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[Petrol Pete]

TCU unit behind this plate in passenger footwell, pop it out and have a VERY close look/smell of the plugs that go into the unit . ATF can track up via capillary action inside the conductors , that is between the copper strands and the insulation they are in .

 

[Chimp400]

It's off to a specialist next week so will see what happens, was told a new conductor plate if it is that wouldn't need coding but my dad didn't fancy the job as he's recovering from a heart attack at the moment.