1996 C36 722.3 Transmission Troubles - PeachParts Mercedes-Benz Forum

holdontight · #1 06-18-2007, 02:45 PM

This is my first experience with the Benz brand and it has been bitter sweet. Since 1995, I have always wanted a C36. I finally got one and love driving it when it is running right. The refinement of the car is outstanding and even working on it gives a sense of satisfaction unlike other cars. Nothing major (until now) has gone wrong, just at 90,000 miles I did not plan on putting a bunch of time into it.

The problem now is the tranny. Under light load, it started slipping in the upper gears at highway speed. I would come to a stop, put it in neutral, let it sit for a minute, then start it back up and it would go fine-for a few minutes. It would down shift after 4th started slipping, then 3rd would run for a while then it would start slipping. Before long all I could do was let it come to a stop, let it sit and then heavily accelerate in 1st and 2nd to gain some momentum and then coast again to a stop (finally made it home.)

I know it can be hard to diagnose trouble with out driving the car, but I would graciously take any educated guess as to what could be wrong other than a standard rebuild. Which leads me to my next question, how are are these trannys to rebuild? I am a fairly accomplished 7 year dealer mechanic (Ford Motor Company) but I have not done too many automatic trannys (many dealerships are having these done off site to be remaned). My other gripe is that the repair documentation on these cars is scarce. I have a manual from ASTG that should give me enough info I believe.

SOOOOO, please any suggestions or guidance will be VERY much appreciated from the most knowledgeable MBZ board on the internet!!

david s poole · #2 06-18-2007, 05:50 PM

it sounds to me as though the filter screens[smaller than your little finger] in the small valve body are blocking up with debris.drop the pan take down the main valve body and then remove the sep plate with small valvebody.turn plate over and you see 4 screws from other side holding small vb.take out screws and release vb.now look in channels and you see a lot of dirt and two little screens.clean them out and replace.be careful to line up screw holes when going back together or when you go to put back main vb. the screws will be very tight and some won't start.nothing larger than 1/4in. rachet or they will overtighten.

holdontight · #3 06-18-2007, 11:59 PM

Awesome advice, thank you. I will check before I begin pulling this apart. How about the level of difficulty of a rebuild of one of these AMG trannys? Rocket science or could could a guy with a reasonable level of mechanical knowledge rebuild one?

david s poole · #4 06-19-2007, 11:18 AM

check those screens first and see how dirty they are then we can discuss the rest.

holdontight · #5 06-19-2007, 11:36 PM

I took down the valve body and found more than I wanted to. Several pieces of what looks to be a roller bearing. About 20,000 miles ago, I did do a fluid change and saw some debris that may have been related to this but I thought that most of it must have been caught by the filter. Along with this, there was alot of the normal filings stuck to the magnet that you might see during a regular fluid change. I also removed the screens and one was very clean and the other had quite a bit of debris in it. It also looks a little bent up like a larger piece of debris hit it. Check out the pics and see if you can make anything out.

Thanks again for your help...

david s poole · #6 06-20-2007, 11:19 AM

unfortunately that trans will need a rebuild.one of the flat cage bearings that allows parts of the shaft to turn against each other without friction has broken and this has created enough clearance so that the two o rings that seal the fluid passage into one of the clutch drums[probably the rear drum that is 4th gear]no longer seal.sorry to be the bearer of bad news but at least you now know.

holdontight · #7 06-20-2007, 12:21 PM

That makes a lot of sense. After looking at the parts break down I see right where you are talking about. This thing will have to be cleaned thouroghly to get all the debris out.

Does anyone have any expreience with this company?

http://www.europeantransmissions.com/

Looks like they offer a reman for about $1100 dollars? Not to bad, I would be willing to pay that for a good reman instead of rebuilding my own. Does anyone know if the 722.328 AMG tranny would be interchangeable with another w202 chassis transmission?

David, again thank you. You have been great source of info to this community....