Jerky auto gearbox on W208 CLK

[mrlozza]

Afternoon All,

I have a small problem (though could be expensive??) with the gearbox on my 2001 CLK. It's the 5 speed auto box with the tiptronic function.

A couple of times recently when I have engaged reverse the car has jerked backwards slightly (like a very lumpy gear change) and then reversed as normal. However, when I then engage "Drive" and move off forward the car jerks again and then drives off in first (or maybe second) gear. It doesn't actually change up so I am then stuck in that gear irrespective of speed.

I then have to pull over, engage "Park" and switch off the engine to try to re-set things in the hope that it is then ok when I drive off again. Has anyone else encountered this and can anyone help? I don't want to have to buy a new gearbox!

 

[gbjeppm]

How many miles has it done?

Has it ever had an ATF change?

 

[mrlozza]

Hi GBJEPPM,

It's done 55,000 miles and has been regularly serviced....according to the paperwork I have. However, the services don't seem to have been done by MB but rather by independents etc (and a Vauxhall dealer who once took it in part ex!!).

I'm not actually sure if it has had a ATF change and, as there's no dipstick on it, I can't see (easily) if the ATF looks a bit knackered. Do you think this could be the problem?

 

[gbjeppm]

Well the forum consensus is that an ATF change should be done at the 50-60k mark, if not before.

It may be something more serious, and hopefully some one more knowledgeable than me will be along to help shortly.

 

[mrlozza]

Hi Matt,

Thanks for that mate. I'll change it over the weekend and see if that improves things. Do you think I need to get ATF from a MB dealer or will the stuff from Halfords do?

Lawrence

 

[gbjeppm]

This may help for your weekend activity. I would use the real MB stuff.

http://www.mbclub.co.uk/forums/showthread.php?t=23969

 

[mrlozza]

Thanks Matt,

I'll probably follow that advice and take the car over to a mechanic I know so he can dispose of 7 litres of old ATF! I will give him those instructions though as it seems like quite a job all in.

Regards,
Lawrence

 

[gbjeppm]

The instructions are for a W210, although I would think that the W208 is very similar.

 

[Dieselman]

Get the codes read. I doubt fluid would cause limp home like this.

 

[gbjeppm]

Listen to dieselman, although the ATF is probably due as well.

 

[mrlozza]

Hi Matt and Dieselman,

Thanks to you both. I'll get the codes checked...but do you know where the filler cap is for the W208's ATF? As it doesn't seem to have a dipstick I'm wondering if I have one of those sealed boxes which might have to be removed in order to drain and refill it?

regards,
Lawrence

 

[Dieselman]

No boxes are sealed, they were 'filled for life', not sealed.

You fill via the dipstick tube, but will need a dipstick or to make one to get the volume correct.
see:
http://www.mbclub.co.uk/forums/showthread.php?t=55242

 

[mrlozza]

Hi Dieselman,

You're a star. I'll check it out when I get home (and find a suitable length of wire) and I'll let you know what I find. I have also asked a mate to meet me later with his scanner and check the codes. It may be worth me mentioning that when it happened (about the fourth time in a month) I can rev up to whatever revs I want (doesn't limit them) and the selector display shows "D" for Drive. However, it doesn't then change up or down and won't let me change gear by the tiptronic mode.

 

[mrlozza]

Hi Dieselman,

Sorry to trouble you again...but I checked the gearbox oil yesterday using a length of speaker wire which seemed to go as far as possible (70 cm of wire went in). On the end 2cm or so of the wire was the faintest smear of fluid but the wire wasn't soaked in it as if it had been dipped. The fluid was yellow in colour rather than the red that I am used to seeing in other cars.

My mechanic mate came round and checked the codes and there weren't any other than one for low voltage to valves...though we think that may have occurred a couple of weeks ago when I had a flat battery.

It looks like the ATF may be low...assuming that the wire went in far enough....but I think maybe I ought to try to get hold of a dipstick before I end up overfilling it. On ebay there are some for sale but they say that they are for the 722.6 gearbox. Would you know what gearbox is fitted to my 2001 CLK 230K tip-auto? If it is that one I'll get the stick and take it from there. Maybe there's a leak?

Thanks,
Lawrence

 

[Dieselman]

It's a 722.6 box. You can't use wire like speaker wire, it needs to be stiff like a net curtain spring. The wire goes all the way into the bottom of the ATF and the measurement is the depth of ATF.
Ignore the overall length, the same dipstick is usedforall models irrespective of dip tube length.

 

[mrlozza]

Thanks DM (hope it's ok to use DM),

I'll probably wait till the dipstick arrives and then check again. I assume from the info you sent me yesterday that a check on level ground with the engine and box hot should give me a fluid depth of 55 to 65mm.

 

[Dieselman]

Yes..
The stick is marked accordingly. Get it hot, cycle through the gears then back to P with the engine running, then dip.
It's a little awkward to feel it hit the bottom of the sump so feed it in gently once 700mm or so has pased. Mark the length to insert with some tape for future use.

 

[Howard]

Hi mate,

I dipped mine not so long ago with a piece of curtain wire , and its approximately 890 mm to the bottom of the sump on a 320 CLK.

 

[Buggerlugs]

mrlozza,

The jerk into drive and reverse followed by no upshift suggests the TCM is in limp home, so you should be able to get trouble codes. What tool is your mechanic using to pull the codes?

 

[mrlozza]

Hi Buggerlugs,

He was using a Snap-On scanner but I don't know which one. I know it's a new model that cost him about £2,500 but have no idea of the model number.

He found some error codes but nothing that he thought would cause the current issue....though I may well get the codes read again in case there's anything new showing.

Lawrence