Moosedes-Benz12

Hi all, I've noticed ATF leaking from my trans. oil pan. A mechanic told me it may be from where the electrical connector plugs into the conductor plate, but we haven't wiped the pan down to make sure. What he said makes sense though, and I hear it's a common thing with the 722.6 trannys. My pan is also slightly rusted, and the car is at 104,000 miles and hasn't had a trans. flush or fluid change yet. I want to change the pan, and want to fix the leak, so while I have the pan off, should I go ahead and replace the conductor plate from off the valve body? Again, while I have the pan off, should I replace the filter/strainer and magnet (if there is one which I think there is)? I've heard that as it leaks, it also creeps up the wire towards the trans. control module. Should I check this too as a precaution? Also, should I flush the trans. or just refill it? By flush I mean filling it, running it, then draining it a few times with new fluid to dilute out any remaining gunk. Ideas?

BTW, my car has been shifting a little harsh between 2nd and 1st and kinda seems to hesitate lately. Maybe due to fluid loss from the leak or bad connection somewhere? Could just be the cars age too.

art_arev

Do a flush the correct way as per the PDF. Change the conductor plate + pilot bushing + tranny filter+ tranny pan seal. You can check the ETC module. Remove it, open it & wipe all traces of oil. You will need a tranny dipstick.

DrX

You don't need to replace the conductor plate if there's nothing wrong with it, or the pan. Rust can be removed and the pan cleaned and painted to prevent recurrence.

There are plenty of parts under your car that will be more than slightly rusted. Are you going to start replacing those too?

As for flushing vs drain and refill a few times, depends what kind of person you are. Do you think doing a job half-properly twice is as good as doing it properly once?

Moosedes-Benz12

Thank you so much for the comprehensive instructions, they look awesome! Just one quick question, exactly what transmission is on my car? The PDFs referred to a few different 722.6 trannsmissions. For quick reference I have a 2001 ML320.

Moosedes-Benz12

You have a valid point, but I just want the peace of mind knowing that I have a fresh trans. conductor plate. Same with the pan. As for the drain vs. flush, I think I will do the flush especially since now I have the comprehensive instructions via art_arev (big thanks).

DrX

Good decision.

The pan is made of thick steel and is never going to rust through.

If flushing, apart from the trans dipstick you will also need a 19 mm ring spanner.

You don't need a threaded hose fitting - use a plastic tube instead as described here: http://www.benzworld.org/forums/w163...l#post10340425

Moosedes-Benz12

Ok, then I won't get a new pan and save some cash. How much fluid should I purchase? And what kind of fluid? I went to the dealer and they gave me ATF 134 for $22 per liter, so I found a a brand called Fuchs from autohausaz.com thats $13.43. Should that be fine?

DrX

If the Fuchs fluid is 4134, then it's on this list approved by MB, so it's good. --> https://bevo.mercedes-benz.com/bevol...236.14_en.html

It comes in a 5 litre bottle, so buy 15 litres. If you read the instructions, it explains that you need 14 litres, so you have some spare for topping up.

Moosedes-Benz12

The one I looked up on autohausaz.com was Fuchs 3353, autohausaz.com also has Fuchs 4134 but it says it isn't compatible with my ML. But I'll take your word for it, also b/c the Fuchs website says it's backward compatible with the 5 speed trannys. It appears autohausaz.com has to update that. I was also looking around and saw that the transfer case takes ATF too. Is it separate from the ATF in the tranny? If so, is there a service interval for that too? Might as well do that too if it's up on the lift, maybe with that left over ATF?

art_arev

Get the Fuchs 4134. That is the correct ATF for your tranny. Changing the conductor plate will be a prophylactic measure & will give you peace of mind for many years. As DrX said, you don't need to change the pan. You have a 722.6 tranny.
Finish the tranny issue, then we can attend to the transfer case. It uses different ATF.

DrX

Yes, it is a separate assembly. No, it is not recommended to use 4134 ATF in the transfer case. MB recommend 3403 ATF for that, which has a different viscosity.

If you want peace of mind, don't put leftover 4134 in the transfer case.

Moosedes-Benz12

Ok last question, I know I've been very curious with a bunch of questions already and I really appreciate your patience.

I've ran the idea (trans. flush) past a few mechanics, and they've all advised me not to even bother with this transmission service. They have even said that I run the risk of the tranny not working after the service. My father and a friend of mine (both mechanics) said that changing the older, thicker, dirtier fluid to new, clean, thinner fluid will not make the tranny run because the newer fluid will cause the clutch packs to slip. I'm not entirely sure what that means. I'm not familiar with the very specific inner workings of an auto tranny, so I'm not sure if what they are saying is truly valid. Nonetheless, I've respected their opinions due to them being far more experienced than me. What's your opinion? Seeing that you did the flush and assuming your ML is working perfectly fine. I'm not entirely sure if I want to go through with this considering all the bad things I've heard.

art_arev

They don't know what they are talking about!!!! Nonsense!!!! Do the tranny service!!!

People neglect the tranny. After developing mechanical faults, they decide to service it(too late). And when the tranny fails(due to neglect) they blame the servicing. This is were these "granny's tales" come from.

DrX

I read these stories and opinions before I flushed mine. I didn't believe any of them.

My trans has done 13,000 miles and 13 months since I flushed it. It's working better than ever. Probably because I replaced all the black fluid that was full of carbon and cleaned the sludge and tiny metal fragments out of the pan (normal wear). I didn't change the conductor plate, according to the "if it ain't broke, don't replace it" philosophy.

You have a leak, so you have to drain it. Do you want to put the dirty old fluid back in the top?

I've been driving this ML every day for 11.5 years. Do you think I have more experience than them?

Moosedes-Benz12

You and art_arev are right. I figured it was a common misconception, and art_arev makes a good point as too how people do the service too late then blame the service. Considering from your post on benzworld that you serviced yours at 174000 Km (~108000 mi) and my ML is at 104000, it shouldn't be too late. Both of you guys have been a great help, and I really appreciate it. The MB community should be proud to have people like you!