If your 722.6 'box stalls when engage gear when cold

[wportre]

If you have this symptom but the box is normal when warm, in my experience it is NOT the TC or TC clutch, although it looks like it. (Normal behaviour when warm rules it out). Rather, in my case, the aging of the gearbox sump gasket had let water in, clogging the filter. Both must be replaced, along with the ATF.

The symptoms are really scary for such a minor problem. A hard stall and jerk. The problem starves the TCC piston, locking it up, so it's like dropping the clutch ona manual.

So PLEASE, before you get bounced into a big bill, do this. Easy DIY: oil from Opie, filter etc from Merc, instructions here.

http://forums.mercedesclub.org.uk/sh...t=16659
http://bestsyntheticoil.com/dealers/amsoil/torqueconverter.shtml

 

[television]

Thanks for that and I will remember that one

 

[delboy777]

I dont have this problem but in about to change my ATF the parts are ordered

 

[television]

I dont have this problem but in about to change my ATF the parts are ordered

You will notice a difference

(key posted yesterday 6 pm)

 

[delboy777]

Thanks Malcolm

 

[wportre]

There's all this beef all over the forums about not using MB part-number ATF, using Shell, Mobil etc. The thing is that, as a member, you can get the Fuchs 236.12 OEM ATF from Opie for 6 or 7 quid a litre plus 5 I think it is delivery. Haven't found the 236.14 there yet though.

 

[shorty1111]

If you have this symptom but the box is normal when warm, in my experience it is NOT the TC or TC clutch, although it looks like it. (Normal behaviour when warm rules it out). Rather, in my case, the aging of the gearbox sump gasket had let water in, clogging the filter. Both must be replaced, along with the ATF.

The symptoms are really scary for such a minor problem. A hard stall and jerk. The problem starves the TCC piston, locking it up, so it's like dropping the clutch ona manual.

So PLEASE, before you get bounced into a big bill, do this. Easy DIY: oil from Opie, filter etc from Merc, instructions here.

http://forums.mercedesclub.org.uk/sh...t=16659
http://bestsyntheticoil.com/dealers/amsoil/torqueconverter.shtml

Hello I noticed your comment on the car stalling in cold weather. I have a similar issue; my car jerks every time when engaging D, regardless of the temperature. It stalled twice, once at 13°C and the other at 10°C, but only twice in the past 6 months. The car shifts gears smoothly, no vibrations, knocking, or jerking during regular driving. Although the oil and filter have been replaced, I'm uncertain if the mechanic changed the gasket—likely not.

 

[Wighty]

Hello I noticed your comment on the car stalling in cold weather. I have a similar issue; my car jerks every time when engaging D, regardless of the temperature. It stalled twice, once at 13°C and the other at 10°C, but only twice in the past 6 months. The car shifts gears smoothly, no vibrations, knocking, or jerking during regular driving. Although the oil and filter have been replaced, I'm uncertain if the mechanic changed the gasket—likely not.

The gearbox sump gasket is normally part of a kit so if the mechanic knew what he was doing I can’t see why he wouldn’t change it for the sake of a few £ .

 

[wportre]

Does the mechanic know what they’re doing? The hardest part of this job is getting the level right. Certainly the first thing I would check in your circumstances. The dip will show quality as well (hopefully new clear and red): with water entry it looks like milk.

 

[Wighty]

Does the mechanic know what they’re doing? The hardest part of this job is getting the level right. Certainly the first thing I would check in your circumstances. The dip will show quality as well (hopefully new clear and red): with water entry it looks like milk.

My gearboxes are both Ok …I was advising you because you were worried about your gearbox gasket ??

 

[wportre]

I think you have mistaken my identity: I am the OP and was addressing @shorty1111 , the bumper.

 

[Blobcat]

I think you have mistaken my identity: I am the OP and was addressing @shorty1111 , the bumper.

Always worth pressing the “reply” button, that way members don’t get confused as to who or what people are replying to.

 

[Wighty]

I think you have mistaken my identity: I am the OP and was addressing @shorty1111 , the bumper.

I hear ya buddy

 

[shorty1111]

The gearbox sump gasket is normally part of a kit so if the mechanic knew what he was doing I can’t see why he wouldn’t change it for the sake of a few £ .

I dont know, because im confused why is this happening car shifts smothly, no noises, no vibrations..

After the initial shift into D, each subsequent shift into D or R is smooth, completely silent; it's so quiet that I can hear the heartbeat. I don't understand what is happening. One mechanic told me that he feels that one clutch is lagging, causing the jolt, and that it is necessary to open the gearbox and replace the clutches.

 

[shorty1111]

Does the mechanic know what they’re doing? The hardest part of this job is getting the level right. Certainly the first thing I would check in your circumstances. The dip will show quality as well (hopefully new clear and red): with water entry it looks like milk.

When I went to the mechanic, he checked the oil, and it was of normal color since I had changed it 4000 km ago. He even checked for any other fluids and confirmed that the oil is clean and healthy.

During the oil change, there were no metal shavings or particles; the only thing he noticed was a dark powder on the hydraulic block. He mentioned that this is normal as clutches wear out. The car has only 150,000 km.

 

[shorty1111]

I would like to add that through diagnostics, there are no errors detected in the transmission or engine.

 

[mioba]

make sure the level is right - see above.

 

[shorty1111]

make sure the level is right - see above.

Mechanic said that level is right…

 

[rich.g.williams]

Heavy clunk when engaging Drive can be one of two things (assuming no transmission internal damage) 1. Torque Converter fault. 2. For whatever reason electronic control of solenoids (or correct operation of hydraulic valves) is absent.

The default condition for a 722.6 operating with dead or absent electronic controller (ie default for no electrics ) is a heavy clunk when going from Neutral to Drive. Reason is that when electrics is absent hydraulic pressures default to maximum, torque converter Lock Up clutch stays off and hydraulic valves default to selecting 2nd gear (and stay in 2nd gear).

A faulty torque converter is quite capable of making a clunk also. Even to the extent of stalling the engine when going from Neutral to Drive. Main mechanism for this being the torque converter clutch not disengaging (sticking).

Photos of inside torque converter:-

TC Post Photos

The torque converter is impressively well built with a very strong looking clutch inside.

When it comes to this initial clunk transmission ATF quality or transmission ATF oil level is a bit of a red herring.

 

[shorty1111]

Heavy clunk when engaging Drive can be one of two things (assuming no transmission internal damage) 1. Torque Converter fault. 2. For whatever reason electronic control of solenoids (or correct operation of hydraulic valves) is absent.

The default condition for a 722.6 operating with dead or absent electronic controller (ie default for no electrics ) is a heavy clunk when going from Neutral to Drive. Reason is that when electrics is absent hydraulic pressures default to maximum, torque converter Lock Up clutch stays off and hydraulic valves default to selecting 2nd gear (and stay in 2nd gear).

A faulty torque converter is quite capable of making a clunk also. Even to the extent of stalling the engine when going from Neutral to Drive. Main mechanism for this being the torque converter clutch not disengaging (sticking).

Photos of inside torque converter:-

TC Post Photos

The torque converter is impressively well built with a very strong looking clutch inside.

When it comes to this initial clunk transmission ATF quality or transmission ATF oil level is a bit of a red herring.

So you think it's an electronic issue even though there are no error codes in the diagnostics? I've replaced all solenoids except for the TCC; perhaps I should have replaced that too? I want to emphasize that transmission adaptation was done, everything was returned to factory settings, and for a few days, there were no jerks, but then they reappeared...

When I shift from N to D, it feels like the clutch engages once, and then after 1 second, it feels like it engages again, a second time...