722,5 tear down which side to start from
 

The ATSG manual when I read it I am not 100% sure which side I start from when I take the tranny apart. The proper way is it main pump side first or driveshaft side first (extension housing) I got the feeling from ASTG manual that I tear down extension housing first. I got the hang of the proper way with governor and brake band pistons so that I do not need to get explained for me.

Mr 64,

I met my twin!!!.... I have mine in million pieces right now-it is completely dissembled!!! I have diagnosed all my problems, and have my all my replacement parts at hand. I've just been interrupted with family member car problems, and then my daily driver E320 went south on me last week, but I am ready to re assemble my 722.5, yet next week I need to drive 400 miles to fix my father and brother's car-very odd occurrence everyone in my family breaking down at once...

I have taken about 200 pictures of my disassemble, and I have about five pieces of service literature to help, Including the ASTG

By the way, what is the reason for your tear down?

Here is how I tore mine down:

1) Obviously you have it on a clean work table?
2) I took the valvebody off first, and put them on a three-inch deep tray that would have them side by side in the tray. The bolts are 10MM(many of them-put them in a sandwich bag(s). No check balls will come flying out
3)take out B1 and B2 pistons(watch out for B1 springs-I have process, so no fancy tool was needed to remove it). Bag the stuff
4)Remove the little vacuum control on the side of the modulator.
5)I left the modulator in because the pin is pressed in where it piviots from would be a royal pain.
6)removed the pump
7)remove K2 drum
8)Brake band 2 should come out
9)remove the nut at the rear of the transmission. A 30mm or 1-1/8" 12-point socket 3/4" drive will be needed. You will have to impact-it-off, or have a helper hold the ratchet while you hammer it off since one edge of the nut is pinged-in(i do not know what they call that, but you need to get a new nut, anyways...) Now, since the nut has a small area for the socket to grab, you will have grind the socket flat to remove the inside chamfer. I used a 30mm socket, and I spent running around trying find "the socket" The closest I came was a socket at Lowes, and I was not going to spend 50 to 100 bucks from Sears, SK,Mac, snap-on, or etc. I settled on complete 3/4" metric socket set with breaker bar, ratchet, case, extension, and 20 large sockets from harbor-freight for about 40bucks with a 20% mailer coupon. The set is not on display, but on the website, and you need to ask for it.

10)remove the rear housing, governor, clutch packs, and their is no secondary pump as outlined in the ATSG.
11)Back to the front of the main housing.Remove this little plastic three finger wedge where B1 was at
12)with an S-curved pick remove the S clutch pack(loosen them too) in the main housing.
13)At the top of the clutch S clutch pack is a very thin sheet metal wedge about the size of a business card.Now use some needle nose pliers to get it out once the S clutches are remove or very loose.
14)you can pull the planetary gear assembly with the front and rear shaft
15)Remove K1 clutch pack assembly.
16)The ATSG said to squeeze brake band 1,and tie it up/compress it. I was able to squeeze it with my fingers to get it off-wiggled it out, and I'm no strong guy-Im skinny.
17)The six hex bolts at the rear of the transmission inside the main housing do not really need to be removed.
18)the BS clutch at the rear housing has to be removed by taking off the clip.

That is how it is. mine is in pieces. I bought a aftermarket rebuild kit from Dacco transmission for about $220. My B2 piston was beat-up, replace that guy. I bought a few simple hard parts.

The reason for my tear-down was I lost reverse on S320,and once a month I think 1st or 2nd would slip as the result of B2 piston. Three of my rear clutch packs were very worn-out. My oil was always gray as the result B2.

I hope this helps,

Lets exchange info?

Martin

Good writeup Martin.

Thanks for your input my problem is no reverse that's why I do the overhaul..

Jim, you are welcome. i was looking at the sequence of the pictures as i wrote it because it is a puzzle. Now, from going this far I would definitely not recommend any Mercedes with 722.5(only used in a few years, and a few cars) The 722.6 is better for DIY'er it will take 1/3 of the time to tear it down and assemble it, and every part is available aftermarket, yet many performance parts too. The only thing for a DIY'er will need for working on the 722.6 is Carsoft or MB-Star to reset the TCM, but the service manuals are on the net(well written), great pictorial diagrams, and service tips.

Here is the list of car the 722.6 was used in:

mercedes transmissions

Martin

Mr 64,

You are welcome,

To fix the reverse problem only, the problem is at the front of the transmission-right next to the main oil pump. You just have to remove the oil pump, compress the springs on the B3 with a homemade PVC plumbing coupling and remove the round snap ring; Separate the B3 from the oil pump, and it is the inner lip-seal on the B3.

The first picture-B3 piston with inner o-ring
Second picture-B3 scored on the inside from hitting the K2 clutch pack which is the click-click roller coaster sound while in reverse.
Third Picture-inside 5dollar lip seal

no reverse / jerks in reverse when cold - Benzworld.org - Mercedes-Benz Discussion Forum

To get to the lip seal:

Step 7 the lip seal
Step 9 the oil pump-lift the inner round gear and wedge for scoring-they should look smooth at the base.If it is scored, you will have to replace the whole pump, or the parts.

If you elect to fix reverse only, just replace all the parts in the last picture, and try not remove K2(the first picture on post19 from the previous link) clutch pack, because it is a pain to line-up the individual clutches.

Do not forget to change the front torque converter seal...

722.5 transmission oil pump rebuid DIY - Benzworld.org - Mercedes-Benz Discussion Forum

Best of luck,

Martin

The transmission has 100,000 miles on it so the plan is to change all seals and frictions plate when I tear it apart. My concern is the hidden seals in K1 and K2 I see when I am at that point. The parts in the extension housing is also for my understanding more troublesome or is it not. I keep you posted what happen in my project I don't need the car so I am in no hurry. You have been very helpful.

Mr.64,

My reverse quit at 125k.K1 the rivets will have to drilled out. K2 the plumbing coupling method will have to be used.

The tricky-one is the one the planetary gear box-See page 66 and 67 of the ATSG for the 722.5.

The extension housing is peanuts-no worry...

Best of luck,

Martin

I can see what you mean that could be the tricky part did you change the hidden seals in K1 and K2?

I have another question did you come up with continuous teflon rings I got some in my overhaul kit and I don't have the tools for those teflon rings.

I got the miles on transmission mix up the transmission has 600 000 km on it I guess that will be 372822 miles.

Mr 64,

I've not replace the parts in the K1 and K2, yet!

The continuous O-rings seals for brake band piston 1 and 2 since I bought a new B2. I do not have to deal with it.I'll deal with B1 when I get to it.

372k miles that is worn out transmission. look for bluing of metal mating parts, bearings...

I'm replacing parts 126,185,197,275,410,189&122. The rear case 394 has a plastic piece that is not available, but you have to buy the whole new rear case.

Martin

You need this document

Great this will help out a lot now I can see the checkballs location too. I am looking forward to get in to the transmission project. I guess if there is a lot hard parts that I have to change I am not sure I will take the cost but we will see. I love this old Mercedes so I hope I will have it running to the fall.

Mr 64,

By the way, what is your 722.5 transmission out of?

Okay, literature very helpful is the one called "TransTech" on post 24, and everything on post 26. They fill the gaps that the ATSG does not cover.

no reverse / jerks in reverse when cold - Benzworld.org - Mercedes-Benz Discussion Forum

Hope this helps,

Martin