Got it all sorted out, transmission installed and working as it should.

here's the rebuild video https://youtu.be/eGNElAtNENo

Many thanks for the video Andy,

I have my 722.354 (400E) out and I'll rebuild the original transmission.
The original transmission failed.. I found a piece of spring in the pan and many metal chips.

I want to install a seemingly good donor transmission in order to get the car going asap.

Two questions:
For the donor transmission would you reseal the outside all the many openings (change o-rings and shaft rings) , maybe open up primary pump and check the Reverse B3?

Is there anything to test on the plastic control cable unit where the vacuum hose goes in as well? (I have the two units...one from the original transmission) and the one from donor. The reason for asking: You can't possibly get to the control cable after install. The W124/ 400E is very tight (much tighter than a W126 I have).

Martin

Hi Martin.
Regarding the donor tx, if you want to install it just for the time you will be rebuilding your original tx....
If it looks OK from outside, and you don't see any visible oil leaks I'd leave it as is. You can replace the o-rings on dipstick, pressure control cable and modulator valve, these are easy to replace. Pull the oil pan and inspect the condition of the oil, if it's clean then just replace the oil and filter.
I'd check the modulator valve and pressure control cable to make sure there's no vacuum leaks and I'd do it at the ends where they connnect to the engine to ensure rubber connectors are goos as well.
I can't tell you for sure, but if you have an older tx there are a number of upgrades to be done, i think B2 piston is one of them.
Good luck

From Martin to Martin

If you have springs in the pan, or open one of these trannnies, and replace the reverse seals... Replace All THE SPRINGS. The plate holding them if it is not cracked, and replace the spring clip holding the plate..

If you have one of these trannies(722.3-722.5), At the very minimum, replace ALL the perimeter seals on the outside of the case as they just cook. Front seal, Rear seal, B2 piston seal, and reverse seal. Since the 722.3/722.4 has very few frictions it is strained a bit more, so parts tend to really cook, and look burned. These old trannies really cook the Brake Band 1 and 2, but most do not elect to replace them as each Mercedes Band is $300 or so. It is real gamble if you do nothing. The B2 piston seal, and B3 reverse seal just cook really fast on these trannies.



Here are some healthy links with manuals, and photos...

Gearbox 722.368 repair manual / tips - Mercedes-Benz Forum

Martin

Thanks Andy
The donor Transmission looks good. The oil was clean and the seller was confirming that trans worked well before removed. So I could be lucky.
I'll probably get it in sealing at the exterior and done. Not sure if it is worth pulling the primary pump and seal it...look if the pump looks fine?



The transmission to be renovated is a 1992 722.354 , at least this is what I thought. But cleaning the old piece that came out last weekend I saw that the aluminum case was sprayed over in grayish color. They sprayed over modulator, kick down solenoid and plugs/covers...
It looks like this was a re-builder's paint job? I don't think the original trans would be spray painted.
Any hints here?
Probably it does not matter much. It all depends on the inside condition of the parts I guess. If the planetary gears and other hardware are fine it should be rebuild-able.

As the damaged transmission had a few symptoms of dysfunction I'd like to understand why it did behave like it did (before I found the steel chips and chewed up spring in the pan.)

I got a 'Precision' Banner Kit for the 722.3 ..out of interest what is inside.
And I am not very convinced that the frictions are the best available. I'd probably get Borg Warner frictions for the rebuild. I am not sure and I have no idea/experience with friction disks.

You are mentioning updates... like the B2 update... yes...where do I get these parts from?

steel plates are available too but not sure if they are needed for a rebuild
Brake bands B1 and B2 should be installed new or are the old ones typically fine?

Valve body: I think I need to open this one up and clean it from any debris/steel chips inside?

Martin

Martin,
thanks, I really have 2 transmission projects going ( A) old damaged transmission to be fully rebuilt and B) used donor transmission, seemingly in okay shape to go into the car fast to get car going)

for B) the donor transmission to go in fast in order to get the car going....
Are you recommending to changing the exterior seals (so donor transmission does not leak unexpectedly at exterior)? Or would you go deeper and if yes what would be on the list as typical point of attention (B2?)


For A) the full rebuilding of the damaged trans I definitively get all parts replaced:
Frictions K1, K2 and B3, (Steel disks if needed) , brake bands B1 and B2,
update on B2 piston.
All seals including the complicated seal rings for the clutches K1 and K2 (remove rivets and replace with bolts).
All gaskets.
I am planning to get the valve body taken apart and cleaned (because I suspect having steel chips all around (as I found in the pan) and I consider these steel chips as one point of failure of the transmission.
As I had chips the transmission cooler was contaminated with chips and also the converter must be contaminated. I hope all the gear sets and primary pump and the bearings are still in good shape.

Question: Are there good sources for replacement parts and if yes what is a good source. Do you have good recommendations for :

clutch frictions, clutch steel disks, brake bands, rubber seals, teflon rings, gaskets, bearings?

Best Martin W

Hi Martin, i don't want to mislead you, so please note... I don't have an extensive experience with rebuilding MB transmissions, so anything I say or suggest it's just my opinion based on the recent MB transmission rebuild, some information I've gathered during my research on the subject and some knowledge accumulated over the years working as a mechanical engineer designing and building hydromechanical transmissions.
I can give you my opinions, but at the end it your decision how to proceed.
Now that we have this cleared .....

Here, I guess, you need to decide, do you install the donor transmission and leave it for good, or you want to rebuild your old transmission and put it back? Further actions will depend on your decision...

Like I said, if you want the donot TX just as a temporary solution then you can change all exterior o-rings if you want to do that, should be OK they are not hard to replace. Just use high temp grease ot ATF for o-ring installation, make sure you don't cut the o-rings. As for openning the primary pump...my dad used to say "don't fix it if it ain't broke". What do you expect to see? If the donor transmission worked fine and no debriss (metal or aluminum powder) found in the oil pan, 99.9% that the primary pump is OK. If you open the primary pump you'll need to replace the o-ring and the paper gasket and since you are already there I'd suggest the primary pump front lip seal. By opening the pump you can just confirm that it's bad if you see scoring or wear on the gears, but then the TX would not worked well since the pump efficiency would have dropped down.

I don't know...but it doesn't make sence for MB factory to spray the modulator or kick down solenoid...

I think so.

What symptoms?

Usually banner kits contain:Transmission Overhaul Kit (seals and gaskets), and a standard set of friction clutch plates.

You might be OK, Service bulletin "Delay engagement in all forward gears" for B2 piston update applies to MB 722.3 and 722.4 1980-1991, I see your's is 1992. You will know when you pull B2 piston out.

It depends..usually they don't have to be replaced. You will have to inspect them when you take the TX apart. If there's some wear you will fill a ridge when you drag your fingernail across the surface. In this case you might want to replace them.

Depends on the condition, B1 has thin friction layer and is not expensive so I'd change it, B2 is another story...needs to be inspected. Depends what failed in your transmission.


Absolutely 100%. Please note, there's a seal kit for the valve body and it's not included with the rebuild kit, I had to buy it from MB dealer. There are about 25-30 teflon rings in the kit, but you will only need 8.

FEW POINTS:
- you have to flash the transmission oil cooler before you install donor transmission. Ask me how...
- be carefull, B1 piston cap is spring loaded, you better make a tool for removal / install, e-mail me for drawings.
- source ATSG 722.3 722.4 rebuild manual, it's a big help.

Im working on my valve body overhaul video, hope to have it finished soon.

Hi Andy,

I dropped you an email about the cooler flush and tools to build.

symptoms of the failing transmission before I found the steel chips and what looks like piece of a spring in the pan:

it started shifting weird but only sometimes... not real bad but something was off so that I started to readjust the control cable which did not help really. Then it went away. This happened a couple if times and I did not know what was going on. As it shifted fine after a while I didn't payed too much attention to it.

There were also a could of weird up shifts that I didn't expect but nothing crazy.
Went away.

Then the car didn't want to pull off a start easily, Torque converter didn't engage as it should I guess... maybe chips in the oil flow restricting something.

This was getting a bit better but not 100% and I decided to change the oil when I found the chips.

Happy to see you valve body video soon.
I love how you handle the job of the transmission repair without throwing a ton of tools and equipment at it.

Martin

I replied back to your e-mail, maybe it went into spam.