My car has 180,000 miles on it and sporadically shifts hard in certain upshifts. It also clunks on occasion when it is downshifting from 2 to 1 when coning to a stop.

I don't believe the trans fluid and filter has been changed since any factory A and B services that would have been done under warranty, if it was even called for then.

Should I change the fluid and filter now, or would that maybe make it worse, which can happen with older US car automatics?

Any other ideas on what it could be?
Is there a way to check the fluid level?
Thanks.

 

Well, if you search and read these two forums, all the answers are there.

180 000 m on a 722.6 tranny is pretty good.

 

Initially Mercedes said the transmission never needed to be serviced . They changed that recommendation years later to every 45000 miles

however if your car has never been serviced in 180000 miles you actually can do more harm than good by servicing it for the first time as you will dislodge a lot of debris

 

Thanks. I read through tons of pages last night, and it is still confusing to me. It seems that it could be:

-low fluid
-trans fluid wicking up to an electronic switch
-the conductor plate

However, with the transmission this old, is the rick of dislodging more debris by replacing some fluid when pulling the pan greater than checking these things and repairing if needed. Or is this trans just about over its useful life regardless?

With the trans just doing harsh shifts sometimes only in one gear to the other (3-4 I think) and downshifting late and a bit harsh back to 1st gear when coming to a stop eliminate any of these potential caused above?

Also, I am getting no malfunctions showing in my dash.

Where do you get the replacement pin for the dipstick tube if I put a bit more fluid in it? Being as the trans is built to handle excess fluid, maybe it wouldn't hurt to throw some more in?

 

Putting too much fluid in the 722 is a bad idea.

The first thing that I would do is to purchase the transmission dipstick "tool". They are available from the MB vendors on-line, from Amazon (about $20) and from eBay (less than $10). Be certain that you get one for the W220 eight-cylinder engines. You will also need the proper Mercedes-approved ATF. Shell ATF 134 should be available at a Shell distributor, very rarely at an auto parts store. It and other MB-approved fluids are available on-line at $12-15 per qt/ltr.

If it were my car, I would take the chance of changing the fluid and filter. If you search, you will find a method of changing all of the fluid, not just the partial change you get by dropping the pan. In fact, I have no idea whether the fluid had ever been changed in my S430 before I bought it at about 190,000 miles, but I plan to change it soon, and have bought the Shell ATF 134, the filter and the gasket.

 

MB WIS for my car with 722.6 basically says: drain and drop pan, change filter; for fluid change fill with about 3.3l, run car to hot and check fluid with dipstick, drain pan & repeat, drain pan & repeat(i.e.2 more times). I guess that negates the "shock" of new fluid, and gets enough out of the TC to refresh the fluid sufficiently.


BTW: make sure your symptoms are rough shifting, and not TC clutch.

 

Yes get the dipstick and locking pin they are all over eBay

just search for " w220 transmission " on eBay from lowest price to highest price , and the few first items to come up will be the locking pin and dipstick as they are cheap

you can check if the electrical connector is leaking by looking at the tcu in the engine bay and seeing if it is wet with fluid . You can also replace the connector without disturbing the internals of the transmission . Here is a video

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