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722.9 transmission service learnings

MB09CLK

New Member
Joined
Feb 3, 2020
Messages
15
Location
Penzance
Car
2009 320cdi clk
I have just dont my first transmission service and I just thought I would note a few things.

First the alloy sump bolts are lightweight crap, I know they are designed to prevent stripping of threads in the transmission but I had one of em snap at 4nm ( all replacement bolts were new) I dont know if I got a dodgy bolt but I have always hated these light bolts anyway, especially the last 180 degree turn designed to nip and stretch at the same time so I ended up drilling and tapping the bolt out and replaced all the bolts with stainless steel ones using a jointing compound to prevent dissimilar corrosion and torqued to 6nm, I did a breakaway and run down torque test on the bolt holes in the transmission and 6nm is no way excessive for these and compared to a light alloy bolt finished off with a 180 degree final turn and 6nm on the stainless they both nip up the same amount, I am thinking the light alloy was done to prevent heavy handed mechanics from stripping threads but as an aircraft engineer I am used to working with delicate alloy components.
Second the patent filter from viaco is a poor fit and I ended up replacing it with a genuine mercedes one as the viaco one drooped down when installed
Third be aware of the lip at the front of the sump mating surface as it is easy to distort the seal on it which will cause leaks.

Thats it but I will get a new sump and fit a drain bung into it so I can do a drain and fill every year without having to drop the sump.

hoping to be able to help the board out with write ups whenever I work on the car as I always do my own work, next up is glow plugs but I dont know if the board needs these sort of write ups?
 
...Thats it but I will get a new sump and fit a drain bung into it so I can do a drain and fill every year without having to drop the sump.

Well done and thanks for the write-up.

I am just wondering if annual ATF change isn't a bit OTT? Unless you do the mileage, of course.
 
Well done and thanks for the write-up.

I am just wondering if annual ATF change isn't a bit OTT? Unless you do the mileage, of course.
Its just a precaution as all these transmissions are is just a big hydraulic pump and heat is the enemy of hydraulic fluid used in atf's , yearly change just makes sure that the heat coping properties stay fresh, we use very expensive hydraulic fluids in the aviation world and we would never let it get to the state it does in automotive applications.
 
FWIW........

FCP euro, they are in the USA has a kit they put together to "upgrade" the 722.9 transmission

This includes a newer filter design{the filter is called SmartMediaTriple filter] and a larger oil pan{an original MB item; the oil pan part number 9062700501] that has a larger / more oil capacity.

The transmission oil pan part number 9062700501, see link for more details on the oil pan.

Mercedes Transmission Oil Pan - Genuine Mercedes 9062700501 | FCP Euro


The upgrade kit listing the part numbers are at link;

Mercedes 722.9 Transmission Pan Upgrade Kit - Pentosin 001989680310 | FCP Euro


The new filter part number is A2222772000, 2222772000

Product Information for the filter posted at FCP's site; see link below, there is a very good animated exploded visual of the older filter design compared to the new filter design towards the bottom of the page. A big difference between the two filters.

Mercedes Transmission Filter - Genuine Mercedes 2222772000 | FCP Euro

I used there upgrade kit when I changed the oil and filter on the 2007 R320 CDI about six weeks ago.

Installing a better filter and an larger oil pan is always better for any transmission.

Regards

Joseph~
 
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FWIW........

FCP euro, they are in the USA has a kit they put together to "upgrade" the 722.9 transmission

This includes a newer filter design{the filter is called SmartMediaTriple filter] and a larger oil pan{an original MB item; the oil pan part number 9062700501] that has a larger / more oil capacity.

The transmission oil pan part number 9062700501, see link for more details on the oil pan.

Mercedes Transmission Oil Pan - Genuine Mercedes 9062700501 | FCP Euro


The upgrade kit listing the part numbers are at link;

Mercedes 722.9 Transmission Pan Upgrade Kit - Pentosin 001989680310 | FCP Euro


The new filter part number is A2222772000, 2222772000

Product Information for the filter posted at FCP's site; see link below, there is a very good animated exploded visual of the older filter design compared to the new filter design towards the bottom of the page. A big difference between the two filters.

Mercedes Transmission Filter - Genuine Mercedes 2222772000 | FCP Euro

I used there upgrade kit when I changed the oil and filter on the 2007 R320 CDI about six weeks ago.

Installing a better filter and an larger oil pan is always better for any transmission.

Regards

Joseph~
Thanks a lot for this, deffinitely on my to do list
 
For anyone interested the breakaway torque value when the alloy bolts were tightened to 4nm and rotated 180 degrees was 3.5nm( this is the force needed to start undoing the bolt from its tight position ), the rundown of the bolts to gearbox was less than .5nm
 
I for one am interested. Keep up the good work. A few photos when you do the glow plugs would be handy.

Out of interest the 4nm then 180 degrees , was that whet MB specced ?
 
I for one am interested. Keep up the good work. A few photos when you do the glow plugs would be handy.

Out of interest the 4nm then 180 degrees , was that whet MB specced ?
yeah 4nm then 180 degrees is the MB spec, I spoke to a friend who works for us who is an ex MB tech and he remembers the old 722 trans bolts being steel not the light alloy currently used, also for comparisson the breakaway on the stainless bolts with jointing compond was 3nm so the difference is minimal on the clamping force on the sump but for peace of mind I am happy with that and there are no leaks either.
 
FWIW........

FCP euro, they are in the USA has a kit they put together to "upgrade" the 722.9 transmission

Yeah, I've seen FCP Euro mentioned all the time by Alex of Legit Street Cars of YouTube fame. They offer lifetime warranty on parts too. I just wish in the UK we had access to some of this stuff. We seem to get the raw end of the deal for Mercs compared with the US.
 
Yeah, I've seen FCP Euro mentioned all the time by Alex of Legit Street Cars of YouTube fame. They offer lifetime warranty on parts too. I just wish in the UK we had access to some of this stuff. We seem to get the raw end of the deal for Mercs compared with the US.
That FCP Euro warranty in the USA Alex always mentions seems mad . When a part wears out , send it back and they give you a new one free, includes brake parts !!
 
That FCP Euro warranty in the USA Alex always mentions seems mad . When a part wears out , send it back and they give you a new one free, includes brake parts !!
And filters, bulbs and wiper blades!!!

I guess they have a good assessment (from their own data) on how many people actually keep cars more than 3 or 4 years?
Most people I know keep a car for 2, maybe 3 years max, often from new or nearly new. Nice if you can afford it, but at that end of the buying spectrum, they're not at all interested in any car DIY whatsoever. Including wiper or bulb changes.

Also note in FCP Euro's Q&A

"Due to the GDPR regulations in the EU we are unable to deliver orders to the European Union"

Bah!
 

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