Total failure to proceed - no drive in 'Drive'

[Zarniwoop]

Wondering if the radiator has burst its cooler and dumped coolant into the tranny.

Been such a long time I cant remember if the CLK has a seperate oil cooler for the transmission but Im fairly sure they were internal in the Rad.

I had no idea that was even a possibility! Sounds slightly scary, if I'm honest. I really hope not, though it would explain the milky liquid I guess...

Tonight I fitted the new electrical socket, gasket and filter, and filled up with 7 litres of ATF. Dipstick experiments were unclear, so in the end I opted for the 'does it feel right' approach, and I have to say that the gearbox feels better than it ever has since I've owned the car - much smoother to engage. It does seem to be holding gears a little longer before changing up, but that may be my imagination.

One thing I will say is that it's testament to the engineering in that 'box that it didn't just explode, given what it had lubricating it. Or not lubricating it, even. The fact that (for now at least) a fluid change has it running again and feeling pretty good is very really quite impressive.

 

[charlysays]

I had no idea that was even a possibility! Sounds slightly scary, if I'm honest. I really hope not, though it would explain the milky liquid I guess...

Tonight I fitted the new electrical socket, gasket and filter, and filled up with 7 litres of ATF. Dipstick experiments were unclear, so in the end I opted for the 'does it feel right' approach, and I have to say that the gearbox feels better than it ever has since I've owned the car - much smoother to engage. It does seem to be holding gears a little longer before changing up, but that may be my imagination.

One thing I will say is that it's testament to the engineering in that 'box that it didn't just explode, given what it had lubricating it. Or not lubricating it, even. The fact that (for now at least) a fluid change has it running again and feeling pretty good is very really quite impressive.

Good result.
I don't think these boxes are harmed by too much fluid, they will throw it out of the breather most likely, that said I've never overfilled by more than a litre.
Lucas transmission fix can work wonders if you have any further issues. Best to mix it with some ATF or it's too thick to get it down the filler tube. Could heat it up though I guess.
It's normal for the fluid to look a bit brown.
ATF starts out red, add in some black from the clutch packs and you get brown. Every 722.6 I ever had has browned the fluid within 30,000 miles but none of them ever developed any issues.

 

[star]

Wondering if the radiator has burst its cooler and dumped coolant into the tranny.

Been such a long time I cant remember if the CLK has a seperate oil cooler for the transmission but Im fairly sure they were internal in the Rad.

This ^. No separate cooler and if the oil that came out was like latte, there’s water ingress into the box. Keep checking the oil. If you have a small sample of the old oil, you could test it for water/glycol. Simple test, otherwise the problem will happen again.

 

[Zarniwoop]

I will indeed keep a close eye on it.

Thanks to everyone who replied - am always amazed at how much good (and often crucial) advice I get when I post on this forum!

 

[Zarniwoop]

This ^. No separate cooler and if the oil that came out was like latte, there’s water ingress into the box. Keep checking the oil. If you have a small sample of the old oil, you could test it for water/glycol. Simple test, otherwise the problem will happen again.

Sorry to bump my own thread, but if it did seem likey that you're right, what work is involved to rectify things? New radiator? Or is it more about changing some seals somewhere?

 

[AnthonyUK]

It's a new rad. Have a search online for Valeo radiator issues for affected models and how to identify.
A 20 yr old rad though would probably be worth replacing anyway if you have detected glycol in the ATF.

 

[star]

New rad or separate oil cooler, if the water has been in the box for a while, it would have damaged the plates in the gearbox and torque converter.