My 2004 C55 AMG's Gearbox.

[Bobby Wright]

After draining the autobox oil and refilling it in the wrong tube I have broken the 722.6 gearbox in my C55. I am wanting to buy a 722.6 gearbox to replace the broken one. This model has the AMG Speedshift on the steering wheel and is that to do with the gearbox or is it electronic. Any help is appreciated massively.

If im not clear im asking,
1. If I can get a 722.6 5G Gearbox off of a different model that uses the 722.6
2. Or do I need to get a gearbox off of a AMG that had Speedshift on the steering wheel.

 

[AMGeed]

Welcome to forum Bobby. Sorry to read of your misfortune.
You will almost certainly need to replace your gearbox with like for like. There are many versions of the 722.6 gearbox with different ratios for different models.
If you put your Vin#(17 digits/letters without spaces) into this decoder it will show the exact version of 722.6 box you need and have.
Checking VIN for Mercedes-Benz | CARInfo


Is there any chance of an indy rebuilding the one you have. Buying a used gearbox is a real lottery, and getting one from another C55 almost mission impossible.

 

[Bobby Wright]

Thank you very much for this info. How hard would it be to find someone to rebuild it?

 

[Bobby Dazzler]

Welcome to MBClub. Sorry to hear of your problems.

Whilst they're a long way from you, this transmission specialist do sub-contract for Mercedes dealers and I'm told Mercedes specialists. I would give them a call and see what they say: Home - VMTP Midlands Ltd

 

[Alex]

How do you know you broke the gearbox? Where did the oil actually go?

 

[brucemillar]

How do you know you broke the gearbox? Where did the oil actually go?

I would hazard a guess (as this has been done before - not me) that the OP drained the box from underneath and 'refilled' down the engine oil dipstick tube? Neither have a dipstick and both have plastic caps. The ATF tube is located low down and under a rubber pipe. There was a chap in the US who did this and bricked the box. I am not sure if it can be resurrected as it will presumably? still have had some fluid (about 4 litres) from the Torque Convertor to circulate, so would not have run completely dry.

I may well be making all of this up, as I was not there. But in the OP's defense, it would be a very easy and simple mistake to make as neither have sticks or clearly labelled caps.

FYI: When I do mine? I suck it out from the top and ignore the filter. IF I want the filter doing? I take it too my local Independent (Wright Tech) who has a fabulous machine that calculates the amounts, temps etc and does the TC. I think for around £170ish and you get a cup of tea.

It may well be worth the OP calling Andy at Wright Tech. He has access to to a great Auto Trans rebuild guy who rebuilt my 124 transmission at a very reasonable price. Andy may also be abe to point you at some further help. These are getting to be very rare cars now (I have a Wagon) and it is worth saving. If it just ran dry? IT may well be something that can be fixed. Be very wary of second hand boxes. They are often second had for a reason and the cost of dropping and refitting could run into a sizeable lump if you have to do it twice!!

 

[Auto-mobile]

I'm assuming all this has been done at home and now the car doesn't drive?

Start again, drain engine, change filter add engine oil.

Add 4.5litres to the transmission tube (the correct one this time )

If there is not enough oil in the transmission then it can't create pressure to work, is this why you think the box is broken?

 

[Bobby Dazzler]

I'm assuming all this has been done at home and now the car doesn't drive?

Start again, drain engine, change filter add engine oil.

Add 4.5litres to the transmission tube (the correct one this time )

If there is not enough oil in the transmission then it can't create pressure to work, is this why you think the box is broken?

Good advice

 

[Bobby Wright]

Thank you all for the advice. I know I broke it as after doing what Auto-mobile said the car will not shift out of 2nd Gear and will not go above 40 mph. And Brucemillar is spot on, I filled it into the wrong tube like a moron.

 

[Alex]

As been said, the gearbox won't upshift if there's not enough oil in it. How much did you put in (second time?) and where did the gearbox oil go if not in the gearbox?

 

[Petrol Pete]

This is bad but not the end of the world as we know it. We are assuming you drove the car and the wrong oil is everywhere it possibly can be in the transmission.
I have the same car had I have had the same brainfart you had and put the wrong oil in I would probably get the on the back of a truck and get the dreaded gearbox flush that is normally not recommended , but in this case its worth the risk. IMHO it can't be more fooked than it is.

My plan would be to get it flushed , drop the sump and filter, remove and clean the valve plate (risk of more damage but what have you got to lose ?) dismantle completely the gearbox cooler lines or at least flush them through. Change the filter fill it up and see what happens. It might have to be re set by STAR. but until you try the above you will never know.

I would certainly do this before hunting for a second hand box that will probably need most of the above doing to it anyway, unless its a guaranteed refurb from a reputable firm. Good luck.

Let us know how you get on

 

[Auto-mobile]

You have driven the car relying on the oil that was in the torque converter, as I said add 4.5 litres of oil, if it still won't change you may have to get the codes erased from the gearbox control unit, alternatively sell me the car for 5k and I will do it