Mercedes 722.4 Transmission Service - why aren’t they all this easy?

JHZR2

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In recent memory I’ve serviced a 47RE and a A343F, and I’ve also done work on 4L60E and other ATs I don’t recall. They all result in me getting covered in ATF, and a stain on my driveway.

Today I decided to service my 1991 Mercedes 300D. It has 232k mikes, needed an oil change, and I didn’t have history on the transmission service. It shifts well but I sporadically get a 2-3 flare, I think when it’s really cold. Not sure if I need a new K1 spring, or if it was maybe fluid related. I figured to try fluids first.

It drains easily, both the pan plug and torque converter. The gasket is a thick molded one that clips to the pan. No issues whatsoever.

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The pan plug had some dirt on it (non magnetic plug), and when I dropped the pan I was worried at first. But it actually has a speckled rough surface, and there was absolutely zero dirt, grit, clutch material, etc. I’ve never seen one so clean.



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The top of the filter had some dirt of some kind (clutch?). But it was only on the top of it. Weird.

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Out went a Mann, in went an MB filter. Probably also a Mann.

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The old gasket probably could have been reused. It may be an original. I was super happy to find that a factory rebuilt transmission is in the car. That means I’m probably good for another 200k miles.

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I put a Dimple super strong magnet in the pan. I put it in one spot and it’s so strong I would have needed to use a tool to get it up. So I left it. No OE magnets in there!

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But it really was great. I hesitate to work on ATs because they’re always a mess. This was a breeze. A joy. Totally clean to do. Why can’t they all be this way. And seriously, why can’t they all use a gasket like MB uses? That Toyota FIPG on the A343F is horrible. Typical old gaskets on domestic AT pans are no better.

This design is far superior in terms of serviceability.
 
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This was the junk on the drain plug:

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None in the pan.

Valve body was nice and clean too.

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There was some glue failure at the filter opening point of the old one. Some of it was loose.

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I’ll need to photograph it better tomorrow.

The filter has a fine screen and media. It seems to have clear glue around the crimped seam.

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What I do is use a vacuum oil changer and suck as much as I can out the dipstick before removing the pan. It doesn't get all of what's in the pan, but enough that you have a chance of not getting a trans fluid bath lol. I take the dipstick and measure how long of a 1/4" hose I need to adapt to the vacuum pump.
 
The 722.6 is similarly easy. Same gasket type. Same drain plugs.

I, too, use the fluid extractor, then drop the pan, because the drain plug on the 722.6 is a 5mm Allen, which is quite small, and it’s easy to distort/strip if it’s been on there for a while.
 
What I do is use a vacuum oil changer and suck as much as I can out the dipstick before removing the pan. It doesn't get all of what's in the pan, but enough that you have a chance of not getting a trans fluid bath lol. I take the dipstick and measure how long of a 1/4" hose I need to adapt to the vacuum pump.
I was surprised on this transmission, I couldn’t get much out that way. Maybe 1.5-2qts. Using both drains I got 6. The dipstick tube has a tight turn that I think makes it hard to get all the way down in. But with a drain plug underneath, who cares?

My brother’s Land Cruiser with the A343F has a drain plug. Even with it “drained” there’s still fluid in the pan. Makes a mess.
 
Looks great!

I actually don't mind some of the newer stuff. I use a pressure vessel to service the Touareg which has a single drain/fill plug. Only time I have spilled is removing the pan because there is a cross member *just* in the way and you have to angle the pan to get it out.

My dad's Ridgeline was super easy. I like the external filter it has.
 
I buy a lot of aftermarket pans, basically so I have a drain plug (GM hates drain plugs). Kinda odd seeing how easy your MB was, worst pan I ever had was on a MB Sprinter. You had to remove the rear mount bolts and jack up the transmission to get the pan out.

Best is still an Allison IMO. External spin on filter and a drain plug.....easy peasy.
 
I buy a lot of aftermarket pans, basically so I have a drain plug (GM hates drain plugs). Kinda odd seeing how easy your MB was, worst pan I ever had was on a MB Sprinter. You had to remove the rear mount bolts and jack up the transmission to get the pan out.

Best is still an Allison IMO. External spin on filter and a drain plug.....easy peasy.
The issue I have with a spin on filter is that you don’t get to drop the pan. IME there’s always junk in the pan. Maybe because it sits there, and there’s magnets in there, it doesn’t really matter. I don’t know. But it seems like it is a good thing to get the junk that remains in the pan out. I was very surprised that there was absolutely nothing in this pan. I put a magnet in, since this pan is a breeze to drop (only six nicely sized bolts hold it on), Ill probably drop it anyway in 36k or so to see what I’ve captured…
 
I've done a bunch of pan drops. No kidding probably thousands.
Looks like a healthy trans.
Love the TC drain plugs. I've only seen them on the older Fords.
Big fan of the Lube Guard red.
 
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