During my digging into my own W126 transmission problem (no reverse gear engagement - since solved via B3 reverse clutch repair), I Googled the keywords 722.3, Mercedes, transmission, and repair, and found the following .pdf file:

http://w126.pp.ru/akp722.pdf

The web site it is on is some form of Russian W126 site (with cyrillic text), but the document itself is in English. It covers the transmissions used in 1995 and 1996 models, but several models of these years use 722.3xx transmissions, and so the info on diagnosis is reasonably valid for W126 models. The document covers 722.3 - 733.5 transmissions. I wouldn't want to use these for actual repair procedures, unless you had exactly the same transmission, but it certainly can help to understand the possible causes of most symptoms.

I have no idea if the web site that this is from had permission to post this document - it just came up via Google.

Bob Schleicher
1991 420SEL - 171,000 miles.

I just want to say thanks for the post that you discovered for the 722 trans it was a big help!!!!!

rschleicher,

Great link, it will surely be helpful. I have a 93 Mercedes 300 SL that has no reverse. Just went suddenly with no warning. It seems to work great otherwise. I haven't taken the time to read all of the link (59 pages), I am assuming that you had to disassemble the transmission somewhat to do the repair on B3 and that it is not accessible from the outside of the case??
Just wanting to determine what I am in for. I have rebuilt several GM transmissions but never a Mercedes.
Thanks, Ed

hurst01,

It's been 2 1/2 years since my post, so I have forgotten some of the details, but yes, repair of the B3 reverse clutch requires removal of the transmission and opening it up. I didn't do the work myself, I just had a local transmission shop do it. My main reason for trying to understand what was wrong was to make sure that I wasn't going to be lured into getting more work done than was needed.

In my case, I had lots of warning of the emerging problem, as I was seeing the typical symptom of reverse gear taking longer and longer to engage (seconds, then many seconds). Then it got to the point where it wouldn't engage at all without blipping the gas a bit (and then it would engage with a lurch). Then, shortly thereafter, it began not engaging at all. The older 722 transmissions (i.e., 722.1, 722.2) had an external reverse band adjustment. But the 722.3 and on require opening up the transmission to repair/replace the B3 reverse clutch.

The question that you have to think about is whether it makes sense to do a full rebuild while the transmission is removed and open. In my case, the mechanic said that everything else looked to be in pretty good shape, so I limited the work to just the B3 clutch, plus general replacement of seals. I am forgetting the price I paid, but it was a bit more than half of what it would have been to get a full rebuild.

Evidently I made an OK choice. I still have the car, which now has 192,000 miles (a bit more than 20k miles since the repair), with everything working fine. Good luck!

Sorta like russian roulette. The job to redo the B3 clutch pack is about 2/3 the whole job to rebuild. The failure always leaves a mess of trash in the tranny. We used to do a few localized repairs back when these trannies had less than a hundred thousand miles.

By the numbers one is a statistical extreme risk taker to not make the whole repair. For the few that have a working trans after surgery the risk is reduced. The real risk is issues from debris that can't be cleaned without total disassembly. Besides the same issues that cause the failure exist in numerous other areas. Unless you are just patching it for a resale dump on someone, you are the one that gets short changed by such short sighted economics.

The point is, whether it is worth it to spend 66% of the price of a complete repair to be driving around with a high mileage used tranny with trash in it. I'd rather just do a used tranny if that were the choice.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Here's a factory document on 722.3 tranny repair... best one I've seen. It's a 7MB download (PDF file).

http://www.w124performance.com/docs/mb/other/tranny_722_repair.pdf

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95 s 500 coupe

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i need help please here is the problems
1-transmission goes only in reverse
2-as you move the shifter there is a rubbing noise as metal to metal rubbing
3-smokes a little with a bad smell from exhaust
4-humming or harsh sound in all shift positions except reverse it gets quitter in reverse

i know its an old thread but here goes in my 1995 AMG 36 with the 722.3 the shifts are still sharp with no slip at all. the kickdown relay has always been removed in my car since i got it, Ie the kick down switch doesnt cause a kickdown. but if i press the pedal from low speeds engaging 2nd gear it will hold it all the way to the 6800 rpm before shifting and on cold days will hit the limiter for a fraction of a second. and when i energize the kickdown soleniod it with the selecor leaver in position 2 first gear will hold all the way till 6800 too.

recently the kickdown soleniod will stick and i have to energize it several times to get it working. but still with it or not energized 2nd would usually shift at 6800 every time..

few days back that changed
the car now shifts from 2nd to 3rd at 6500 with the kickdown energized or not and first will never go beyond 6000 now with the soleniod engaged even.

the box still shifts the same way ie no slip or delay in engaging drive or reverse, it just doesnt hold the revs by itself as before on wot. i tried adjusting the throttle cable and the kickdown cable and the max shift point didnt change.

need ideas on what might be the cause....

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Jay,
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-1995 Blue W202 C36 AMG (M) SOLD ;(
-1995 Black W140 S500 (Lady)
-1992 Black W124 E300 (Dima) (Ex-Mosselman
Twin turbo Kit).
-1988 Black W124 300 E 4-Matic.(Nadeen)
-1983 Brown W126 500SEL.(Old Lady)(Sold)
-1981 Gold W123 280CE.(Dareen)(Sold)
http://www.youtube.com/user/jayrasheed

Just a reminder to all that the included link pdf file is a super file.

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1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

Additional transmission docs are posted here:

http://www.w124performance.com/docs/mb/transmission/

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