jkv11503

I've attached the official MB service document for performing a transmission flush. I know these procedures have been floating around the forums for quite some time in one form or another; however, I don't think anyone has bothered to tell the MB techs about them.

Every MB service center that I've talked to uses a special "flush machine" rather than performing the procedure as per this attached document. Why is that? Are they afraid to get their hands dirty, are they just plain lazy, or is the use of a flush machine far superior to the official MB procedure?

Also, where does their flush machine connect to the transmission lines? I'm assuming that it connects near the transmission cooler, which means that any old (dirty/contaminated) fluid that exists between the machine and the pan/filter will have to pass thru the new filter before reaching the flush machine. It seems like that would contaminate a new filter with old fluid, right?

Reviewing the MB documentation, it looks like the problem of contamination is avoided by removing the oil return line connection from the side of the transmission, thereby ensuring that the only oil passing thru the filter during the flush is the new oil. Why do the MB service centers not use this procedure?

I've looked everywhere and I can't find any MB documentation that speaks of using a flush machine. If someone has a copy of the flush machine procedures, please post it here or pm it to me. I would love to see how it compares to MB's procedures. Thanks.

Toolman_Johnny

The short answer is...there's more than one way to skin a cat. Lots of debate about the pros-cons of each method...and how effectively/thoroughly each method can (or cannot) replace ALL of the old fluid with new. It's naive to think that any transmission servicing will ever replace every last drop of old fluid with new. Sort of like an oil change. Any method available will invariably involve some mixing of the old fluid with new....there's simply no way around it (unless of course you disassemble everything...and I mean everything...torque converter, tranny, cooler lines, radiator, etc). Having said that, I think most would agree that the more old fluid you can get out, and exchange with new, the better.

This is the method I used, and it worked brilliantly. I happen to like removing the pan, cleaning it (and the magnet), and at the same time, replacing the filter. but everybody has their reason for one method or another.

jkv11503

I'm with you, Johnny. Dropping the pan, cleaning it, and replacing the filter seems like it should be standard procedure when flushing the transmission.

I'm still amazed that not one MB service adviser that I've spoken with nor the customer care rep at MB USA knew anything about the MB transmission flush document that I attached in my first post. The MB USA rep actually couldn't locate the document even after I gave her the document number. She asked me to email the document to her. Basically, from what I've learned thus far it seems like all the service centers consider the filter replacement and transmission flush two separate jobs. I guess that's their way of making more $$$.

Taylor-Made'90

Okay, I've gotta question. The pdf file says 14 liters are required for a complete flush..

What if I just wanna drain and fill?

That seems like an awful lotta Tranny fluid.


And is the MB synthetic fluid expensive?

Toolman_Johnny

The problem with a traditional "drain and fill" (draining pan and refilling), is that you would only replace less than half of the fluid. I used 8 1/2 quarts to do mine. Not sure why they recommend 14qts. Perhaps just to be doubly sure that you get every last molecule of the old stuff out. I dunno.

edwinwalke

For those that are interested in saving a few bucks I just ordered from a Shell distributor a couple of cases of Shell ATF 134 (MB Sheet 236.14 Approval) transmission fluid for $20.31 for a case of 12 quarts. This is the Mercedes Benz fluid approved for all 722.6 5 speed and 722.9 7 speed transmissions. Quite a bit of difference from the $12 a liter plus price for MB Fluid and Fuchs Titan 4134 that I have been using.

I just googled Shell Distributors and found one within 20 miles, gave them a call and ordered over the phone.

Toolman_Johnny

Wow...you got one heck of a deal on that fluid. I used the same stuff (Shell ATF 134), but it cost me almost $5 a quart when buying a case from my local distributor. Makes me wonder if they gave you the right price. Under $2 a quart for synthetic fluid is awfully cheap. Good going.

edwinwalke

I told the guy that it was cheap and he said maybe we should raise the price. I bought 24 quarts which was $42 and some change with the tax. The Distributor (Quarles Petroleum) is in Opal, VA. Didn't ask but they may ship for a fee.

lkchris

Flushing is their way of flushing your wallet for sure.

This is the transmission that originally called for lifetime fluid fill.

Flushing is just a "feel good" exercise, nothing more.

And, just to be clear, this flush procedure is for 2003-2005 W211 only, i.e. those with the 5-speed and NOT the 7-speed.

http://www.thecarconnection.com/tips...ing-of-america

Toolman_Johnny

If you ever saw the transmission fluid analysis results after about 30-40K miles, you wouldn't be saying that. A fluid change is cheap insurance.

mac911

For those with the 7G Tronic, is there any fear of the dealers do it wrong? Or, with the 7G Tronic is there really only one way, the correct way? I ask this, as I know the 7G Tronic service is much more expensive. Therefore, hopefully it's done correctly, or not from what you've seen?

novae500

i'm by Dulles airport. Will be giving them a call and seeing if they can ship to me when its time to do a tranny flush on both my E classes.