CLK 270 CDI gearbox problems - do I need a new 'box?

[Zarniwoop]

Hi all,

I have a 2002 C209 gen CLK 270 CDI. I recently discovered that the radiator has been leaking coolant into the automatic transmission fluid, and this seems to have killed the gearbox. It will now rarely engage drive or reverse at all, and you lose drive or reverse as soon as you meet any resistance (i.e. a slight incline). I've not been driving it since discovering the fault, but have needed to move it around the yard a few times, which is how I'm aware of the decline in the health of the 'box.

I have a couple of questions, which I am hoping people who know a lot more than I do might be willing to answer for me...

(1) Is the simplest or cheapest solution likely to be to replace the whole transmission with a good secondhand unit?

(2) If it's a YES to the above, do I need an auto box from exactly the same year and engine of car, or would any Merc 5-speed automatic gearbox work?

Am also wondering about breaking the car for spares, but that seems a shame. Felt luck to find one without any rust, and spent an awful lot of time fixing and servicing so much else only for the gearbox to die. Sad times.

Thanks in advance!

 

[Chrishazle]

Sounds like you have a Valeo radiator with the transmission cooling rad inside it, a known and documented problem, do a search for Valeo Radiator on here and Google, you'll find a lot of info.

 

[alexanderfoti]

1. Yes, + Torque converter + New radiator.
2. As long as the first 6 digits of the gearbox variant match, it will fit EG 722.643

 

[V6Matty]

@00slk is pretty familiar with these swaps now

 

[00slk]

Hi all,

I have a 2002 C209 gen CLK 270 CDI. I recently discovered that the radiator has been leaking coolant into the automatic transmission fluid, and this seems to have killed the gearbox..........................

I think most old Merc's end up in breakers yards because the trans die, if you can look for a c209 CLK 270 like yours in 'spares or repair' so it can be test driven. If you can buy cheap enough, use the box and TC and rad and then either sell it off or break it and recoup your money
I've done this for years

 

[horatio]

Glad I binned my valeo rad. A lot of people say the problem is gone because “it would have happened by now” but you still read occasional stories like this.

I bought a ‘Behr Hella Service’ radiator from ECP which was made in China & looked so cheap & nasty I returned it. Nissens much better.

Shouldn’t be hard to find a decent gearbox or silly expensive to install either. Use one of the breakers with a good rep. Cheaper than buying another car which might come with its own surprises anyway. Good luck.

 

[Zarniwoop]

Thanks all for the responses - much appreciated. I'll starting hunting for a secondhand box. Getting a breaker is also a great idea, but alas I wouldn't easily be able to house it while stripping it, if you see what I mean. And to be honest, since moving back home to Cornwall I've discovered that the local used car market is a bit limited compared to a big city, so might take a while to find one in any case.

I hope this isn't a daft question, but how do I know what number my gearbox is, as per what @alexanderfoti says above?

 

[ajlsl600]

1. Yes, + Torque converter + New radiator.
2. As long as the first 6 digits of the gearbox variant match, it will fit EG 722.643

Can he not fix rad, flush trans and get away with it I think right now tc half water half oil so no drive?
Another shxte design

 

[Blobcat]

Thanks all for the responses - much appreciated. I'll starting hunting for a secondhand box. Getting a breaker is also a great idea, but alas I wouldn't easily be able to house it while stripping it, if you see what I mean. And to be honest, since moving back home to Cornwall I've discovered that the local used car market is a bit limited compared to a big city, so might take a while to find one in any case.

I hope this isn't a daft question, but how do I know what number my gearbox is, as per what @alexanderfoti says above?

Do a vin lookup on you car and it will show the gearbox number

 

[alexanderfoti]

Can he not fix rad, flush trans and get away with it I think right now tc half water half oil so no drive?
Another shxte design

Yes worth a go! If the car is not worth £££ then less to loose by swapping RAD and changing oil a few times. We have an E55 in now with suspected glycol contamination and did an S55 a month ago that had the rad fail so badly that it pushed all the engine coolant through the gearbox, then blew the oil line off the rad pack and emptied the gearbox, locking the whole thing up.

 

[ajlsl600]

Most engine designs go to "some" trouble to keep oil n water sepperated so I think that's another crap design, making trans cooler intereral pt of main rad. An air, fan cooled trans rad with earoquip hoses a far more "quality" design.

 

[horatio]

Believe it or not this is a common problem on the Lexus LS430 too. Owners often fit a separate atf cooler as a precaution.