722.4 no reverse engagement

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Can't believe the bellhousing difference... bigger engine needs bigger housing.
http://w126.pp.ru/akp722.pdf
The internals should be the same so I would swap it all out. Do a quick
measurement of the width of the body where all the clutchpacks on the housing and compare it to the old one.
Check the valve body... should be the same.
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By looking at partnumbers (through www.detali.ru) it appears as if internal parts will fit. Planetary assembly, shaft and a few other parts are different part numbers, but all seals, clutch plates etc. are the same, so dimensions are necessarily the same. That makes it worth the try.
The valve body itself and spacer plates have different part numbers, possibly due to at slightly different hydraulic design or maybe just due to different shift points. I will be at bit more cautious here.
Unfortunately, I do not have the time until the weekend.
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When swapping parts, I found - of course - that some gaskets (front cover and rear case in particular) couldn't be reused, and I had to wait for the parts to arrive. This was exactly the reason (waiting for parts) why I didn't want to do the repair in first place.
Anyway having the transmission apart I found the reason of the lacking reverse to be the clutch (brake) friction discs of B3 to be worn down. I could see by wear marks on the inside of the B3 piston, that the B1/ K1 drum had stopped the B3 piston from engaging B3 - therefor no reverse.
I was suprised by looking at all the gears and bearings - there was no visible signs of wear after 750.000 km. Seal material was hard after 20 years of use, but still tight. B1 and B2 brake bands were not as thick as the new ones, but still plenty of friction material to go the same distance again. I didn't open K1 and K2 packs (yet) and have therefor not determined their condition, but they were working well.
Seen in the rear mirror, I should just have done the complete overhaul in the first place, using the overhaul kit available. It would have been cheaper and costed less work and worries.... if I had just known the good shape of the gears.
It was a time consuming job to do (because it was first time I tried), but it was really not that difficult. Removing/installing the transmission was in fact much harder.
The lesson learned (and to be shared) is that the gearbox itself will run forever, and an overhaul with friction discs and all sealings will give you a virtually new gearbox. Really not a job to be afraid of, as long as you observe cleanliness during the overhaul.
Now it works well. It shifts a bit too harsh to my taste, although the vaccum control has been turned fully ccw. There is a relatively heavy leakage from the place, where the secondary pump is if fitted (not in my case), which I still have to clear.
Thanks for the help.
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Hi Jens,
I am sorry you had to learn this the hard and expensive way. Perhaps you can rebuild this 'spare' tranny and recoupe some of your cost.
So, I am assuming you swapped all the parts out of the newer tranny into your old casing. I can only assume that the springs used in the 600 clutch pack are stronger than the one in your original tranny. Hence, it shift harder.
I don't know if swapping the vacuum modulator from the newer tranny into your older one will solve this problem since more powerful engine will have more torque to 'slip' the clutch pack for smoother shifting.
I should have thought of that different engine has different bellhousing. When I swapped mine, it was from newer 2.3 190E into older 2.3 190E... so no difference in the housing..
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I don't really feel that sorry. In the end, I still have a new gearbox inside - and gained some more experience.
Meanwhile I've for free got hold on another .358 tranny (same bell housing as mine), which is leaking but otherwise OK. Now I have plenty of spares (which I probably won't need), and I may make a rebuild, if someone should need it.
I checked part numbers on clutch and brake band springs, and they are the same as for the V12. So harsh (fast) shifting is not due to this. I cannot say about pistons and springs inside valve body, which could be different (valve body part number is different although all channels and connections are identical).
Vaccum Modulator part number is however different (probably providing different modulating pressure), and since that is exactly what controls the shift behaviour, I will try to put in the old unit, next time I get it lifted.
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That's a positive view. I like the way you think. Congrats on your successful overhaul.
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I don't really feel that sorry. Afterall, I still have a new transmission inside - and gained some more experience.
Of course it would have been nice (very) to have saved the difference from an overhaul kit to the one I bought. But as you say, maybe someone needs a rebuild tranny, which I could do (meanwhile I got one more leaking but otherwise functional .358 tranny for free), or at new converter for a V12.
Anyway, I checked part numbers of springs for clutches and brake bands, and they are all the same for .368 and .362. I cannot tell about pistons and springs inside the valve body, which has a different part number as a whole, but otherwise is identical in terms of internal channels, position of valves, connections through the intermediate plate etc. Thus could give a different shift behaviour.
Vacuum modulator does have different part number and probably a different modulating pressure range. Since this has exactly the purpose of matching the shift transition, I will try to swap back to the old one, next time I get it lifted.
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Thanks for the latest status update. In fact, that is the best part of the discussion, so we know the actual reason of the failure. Many times we see the symptoms and suggestions but don't know the results.
I have been watching this thread closely, since I also face the question what to do with my 84 190D transmission. I first found water in ATF about a years ago. The radiator was immediately replaced. A few months later, the same milky ATF appeared. The car almost does not move right now even after fresh ATF. I now suspect rain water though I cannot determine where it gets into the tranny. I am thinking toward rebuilding but cannot find much information about "how".
Based on your description, a rebuild does not need special tool. If removal is the most difficult part, I am sure I can do it (as long as I can find the time to do it). I do have the ATSG manual.
Jens wrote:

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Wherever you get the rebuild kit, you can buy the manual on how to rebuild it.
I have done rebuilding my 722.3 tranny and it wasn't hard for the work. You do need some basic tool such as a circlip spreader. I think there is also a snap ring so a snap ring plier is needed too... cheap at Harbor Freight.
The water damage the friction materials and maybe some seals.
You do need to take time to do this work... I'd spread it over 2 days so your mind is clear. Friction plates and bands needs to be soaked in ATF for at least 24 hours if I recalled correctly... unless it is a couple of hours.
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Tiger, thanks for the additional info. My confidence is higher after seeing this thread. Yes, I should have enough tools to do the work. My wife will probably think I have too many :-)
I look in EPC. There seems to be kit for the internal rebuild, but shouldn't I also renew the seals or parts in valve body? There are not many shown in EPC. Another option is I can send it out to MB tranny specialists. The price I was quoted is $400 - $500 (just the valve body). Many places offer entire rebuilt tranny around $1500 (plus around $200 for shipping).
Tiger wrote:

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That is the delimma for us in USA... we can get cheap rebuild. However, my experience with Cottman Transmission long time ago was not good. I was young and maive and they tricked me into a rebuild.
The transmission didn't last... just a little past 1 year warranty. Not every rebuilder will replace everything that is in the basic rebuild package. They can buy individual parts and determine what is just needed. They want to save as much money as possible because 1 year is plenty of time for the tranny to survive. Hardly anyone rebuild valve body... they probably just clean it up. What I am saying is they will reuse as many parts as possible because it is only 1 year.
Transmission shops around here demands $2500 for a rebuild. I can source $1250 rebuild but no experience with them but they are close by my house.
Rebuild kit can be bought anywhere... no need to specific MB parts. Outfits like Jaggi will provide you a complete kit for valve body.

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@Wan-ning Tan
An overhaul kit from Mercedes is priced at 350$. I don't know exactly what it contains. Accourding to EPC markings, it is just sealings and gaskets, but I cannot make it add up to that value.
Anyway, according to the experience I just gained, you should replace ALL sealings and gaskets, inspect other parts and replace as necessary (probably nothing needed). I would in any case replace all friction plates of K1, K2 and B3 - they are not that expensive.
And I would get a couple of brake band thrust pin holders p/n 140 277 01 51. They break easily and cost very little.
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The ATSG manual is quite detailed in the procedures of dismantling/ reassembling. It refers to some special tools, but in general you can do without them.
The B2 springs are quite strong, but once you have taken off the valve body etc., you can use an ordinary large clamp to span accross the transmission body to compress and remove/fit the spring set.
There is a number of clearances to verify, but in general things fitted before and will fit again with new K!, K2 and B3 friction plates (unless bearing, thrust rings etc. are really worn - then you have an entire different problem than just clearances).
Be careful when taking apart the valve body. Check balls, springs etc. may fall out. But don't be afraid, if it happens (as it did to me). The manual is quite accurate in pointing out the locations.
The manual specifies 12 hours for the job (when tranny is out). I spent some 18 hours on taking apart the two transmissions and assemling them into one, including a couple of hours to thoroughly clean the bell housing (to avoid dirt in the assembly work), but excluding taking apart the clutch packs (they were new from the donor). Much of the time was spent on reading and understanding the instructions.
Good luck.
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Thanks for the good head-up. I did worry about some of the special tools mentioned in the ATSG manual. It is great news I don't really have to use them.
From what you know about the construction of the housing, where do you think my tranny can get the water from? It is a lot, not just drops. I estimate there is at least a cup of water mixed in ATF. Radiator was replaced immediately after the first occurrence. I noticed it again a few months later while there was no loss of coolant at all. The tranny does leak (about a liter every 15-20k miles).
TIA
Jens wrote:

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Tranny cooler line
Vacuum modulator but it would suck ATF out of tranny.
Tranny pan...
No other way in.unless you got leak but leak woudl leak ATF.
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ATF runs through a closed circuit. Generally the ATF is under pressure, which decreases through the various actuators etc., before it passes the radiator for cooling (or heating to the operating temperature of 80C) until it finally arrives to the oil pan again (at zero relative pressure).
The circuit breathes to the atmosphere through a breather at rear top of the housing and through the dip stick (leading to the oil pan).
Water will only enter the ATF circuit, when water pressure is higher than ATF pressure at the point of entry. Or it more or less drips into the oil pan through the breathing places or another unintended hole (unlikely - from where should the water come? - I cannot see it, unless you use the car in some amphibious way).
In the radiator, water is present with a pressure significantly higher than the ATF passing through. This is true, when the water is hot - otherwise it is vice versa, and ATF could enter the coolant. This is still the most likely point of entry, even if you don't see the a drop in coolant level, and even though you already replaced the radiator (from where did you get it?).
There is up to three vacuum connections to the tranny: Modulator and two connections to the throttle position cable (one for Standard/ Economy mode selection if present, and one for delayed upshift when engine is cold). In all cases they will never carry water (unless your vacuum circuit is filled with water, which is again more or less impossible), and they will never provide pressure. Leak in the vacuum actuator diaphrams would suck out ATF from the tranny and contaminate your vacuum system, which would be an entire different problem (happened to me).
Go for the radiator once again.
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.... and then rebuild the tranny (after having resolved the water problem) as the leakage indicates anyway.
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No, I have not bought anything from them but I would not have a problem ordering from them. There is another MB tranny part supplier... Jaggi... do a search... and same is there... they will supply you parts.
Those prices they quoted on the parts are actually wholesale prices that tranny shop pays... so you can see how much profit is involved when you are trained to rebuild tranny. There are some tricks and experience that makes a difference on a tranny that will last a long time.
On rebuilt transmission, their prices are fair... I can get them even lower but don't know their reputation... at least they are local to me and they do offer extended warranty on their tranny. I think last I saw the prices... I can buy tranny, have them put it in for a hundred or two more than the price you have seen.
For newer tranny... I think it is like $700 cheaper. Anyway... hope these info helps.
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