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722.6 Sudden Major Leak from Bell Housing

49K views 161 replies 9 participants last post by  tabijan 
#1 ·
Hey guys,

So I was driving driving yesterday and while stopped at a light a noticed a little light smoke coming from the underside of the car. I pulled over and noticed the smell of transmission fluid right away. I looked under the car and transmission fluid was dripping almost pouring out of the bottom of the car. Fortunately I was a few miles away from my house. You can see the drip trail leading to the car from the pics below. This is from me backing the car up into the spot near my house. I put the car up on jacks and noticed It's coming from the bell housing. The only thing I checked or tried to check was the drain plug on the torque converter. The plug and washer are new from when I changed the transmission fluid, but the plug along with the rest of the torque converter were soaked so I couldn't determine if that is the issue. it seems like it is coming from the transmission side not the engine side so my guess is that it is the torque converter seal or the torque converter itself but I can't be sure until I get the transmission off.
My questions are -
Is there anything to know before diving in and taking the transmission off? Or are there any other simple checks to look into before undertaking such a heavy job?
If I replace the seal on the torque converter should I replace the torque converter as well or just leave it? Anything else to replace on the trans while it's off the car without going to deep into the internals?
Could the amount of fluid be an indicator of what part is failing? I might have at least lost a quart driving 2 maybe 3 miles.

Everyone's advice would be appreciated. MAVA if you want to weigh in that'd be great.
 

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#4 ·
Thanks!

Jeremy,

Now, you are leaking from the point where the union of the transmission bell housing, and the engine? not from body of the transmission to the bell housing?

How many miles on the clock? These cars are not getting any younger, and the heat is just kills all the rubber seals on the perimeter of the transmission, and this is true for any transmission, and you are experiencing that now.

Lets assume it is the front seal, and you are going to remove the transmission, and do not want to do a full rebuild.

I would change the TC(torque converter) with a updated one from Wit-Trans, Front seal, Front bushing, rear seal, Interlock(or the rubber), shifter seal, rear interlock seals, dipstick seal, and top vent seal

It does require you to remove the bell housing from the transmission to front bushing, so that is your call, but the front seal will be easy once the bell housing is off...

Now, I would rebuild it if were going through this, these 722.6's are easy to DIY, but I do not know your skills, but I assume you have the skill to Diy and remove it. You can do it...

Download the manuals, and take a deep thought if you want to embark on this task...

http://www.benzworld.org/forums/w140-s-class/2544649-new-revised-722-6-service-manual.html

I have about 250 High Resolution pictures of the 722.6 rebuild process. Send me a 16gig flash drive with a pre paid return postage envelope, and I will duplicate my info, and you decide what you want to do...


Martin
There is 216k on the Clock. Yes it is the union of the bell housing to the engine so its in the bell housing itself. not Transmission to bell housing leak. What is the value of updating the torque converter rather than leaving the old one assuming the old one works fine.

I am going to print out the manual today at work and take a look at it tonight and get back to you. How long did the rebuild take you? And what exactly would I be rebuilding vs leaving?
 
#3 ·
Jeremy,

Now, you are leaking from the point where the union of the transmission bell housing, and the engine? not from body of the transmission to the bell housing?

How many miles on the clock? These cars are not getting any younger, and the heat is just kills all the rubber seals on the perimeter of the transmission, and this is true for any transmission, and you are experiencing that now.

Lets assume it is the front seal, and you are going to remove the transmission, and do not want to do a full rebuild.

I would change the TC(torque converter) with a updated one from Wit-Trans, Front seal, Front bushing, rear seal, Interlock(or the rubber), shifter seal, rear interlock seals, dipstick seal, and top vent seal

It does require you to remove the bell housing from the transmission to front bushing, so that is your call, but the front seal will be easy once the bell housing is off...

Now, I would rebuild it if were going through this, these 722.6's are easy to DIY, but I do not know your skills, but I assume you have the skill to Diy and remove it. You can do it...

Download the manuals, and take a deep thought if you want to embark on this task...

http://www.benzworld.org/forums/w140-s-class/2544649-new-revised-722-6-service-manual.html

I have about 250 High Resolution pictures of the 722.6 rebuild process. Send me a 16gig flash drive with a pre paid return postage envelope, and I will duplicate my info, and you decide what you want to do...


Martin
 
#5 ·
200k is the boundry of leaking major seals and very worn frictions. I anticipate that as I'm 400 miles from 200,000 miles.

I have been doing this for a while I can rebuild one of these in six to eight hours, but it will take you three to four times a long.

Replacing all the rubber seals, and replacing all the frictions. Also replacing the three bushings(mandatory-especially the K2 bushing). Replacing a bonded piston, and the two sprag bearings. Ahh torque converter always on the 722.6..

Martin
 
#6 ·
I just want to make sure that I have everything down. If I choose to do a rebuild go for the front and rear seals, All of the clutch friction plates, but it looks like it would only be sold in the entire packs.

When you say bushings you mean the bearings in each of the kX drums?



Are all of the friction disks mandatory?

I am also curious why replace the torque converter if this one is working. What's the difference between this one and updated one?

Sorry for all the questions. I am seriously considering it, when I changed the transmission fluid I noticed a few tiny little pieces in the oil about 10k ago, reading watching reading up the link you posted up in this forum and the manual I think it may have been a few rollers from one of the bearings (probably K2 since that seems to be the most common failure). It seems like a cool project.

in the attached picture is what I would need to replace (I didn't highlight all of the clutches and all the rubber seals because they are a little more obvious I think. Is there anything I missed or mislabeled?
 

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#10 ·
Ha! Right now I'm driving through southern Oregon toward South Pasadena for a week in a rented Enterprise van. Probably be my last driving trip to LA ever. From now on I'll be flying down and renting a car.

Anything you need me to pick up in Sacramento and deliver to LA? The van is nearly empty.
 
#13 ·
Just check it and there are no Pick-your-part in Las Vegas.
See 2 JY but no net inventory.
I used to live 1+ hr of driving from MAVA and even I never needed transmission rebuild, having him so close sure brought confidence in buying MB.
Now MAVA, how good are you with 7G ? :D
 
#15 ·
The vegas yards have old cars-Been there..

Pick Your part , You got San Berdoo, Riverslide, and Fontana at about 3 to 4hours away..

The 7Gs are like the 722.6's-most of the same internal drive parts-no lip seals :angel Conductor Plate can be fixed in most cases. You should be on the updated pan. In my book you pull the adaptation values every year, so you know the fill-cycles of each clutch pack. Easy to rebuild, you can substitute the aluminum bolts with Stainless-Bolts. The 4-matics of the 722.9 have issue with the internal transfer box-lube issue, and .9's now have roller bearings for a front pump bearing..

Martin
 
#18 ·
Ohh Buddy, those roller things are real bad news. I would hold off on buying parts until you find where that came. My experience says they are coming from the planets on the main shaft, but these 722.6's(all flavors) have a bearing assembly on one of the shafts...

Not to scare you, but this is the consequences of the those bearings....

http://www.benzworld.org/forums/w140-s-class/2212618-722-6-slip-shudder-d-r.html

This is all because of K2 bearing is worn-out(See post 14 third picture)

Martin
 
#19 ·
That is what I thought too but it's been driving fine for about 10k since I've found them with no issues. I'll see if I can cancel the order through transmissionparts. I guess the trans is just going to get torn apart this weekend. I'll post up pics and report back. And wait for your advice. :bowdown::bowdown::bowdown:

I am still curious about the clutch clearance if you don't mind answering it,It might make more sense when I'm in there but for now I don't understand how they go in more than 1 way if there's a snap ring, and I'm guessing a groove for the ring so how does it go out of tolerance?
 
#24 ·
Give me your vin, so I can see all the options for the Diesel 722.6

The Spring Clip does not get tossed for a new one. What one does is assemble the clutch pack with the new soaked frictions(Remember we soak the new ones in Trans Fluid for a few hours). Assemble the whole thing with the existing ring, and measure the gap clearance with the feeler gauge, and you find the gap 1.2mm, but it needs to be 0.7 mm for a minimum, and the thickness of the present spring clip measures 2.0mm. Mercedes makes the spring clip at thickness at 2mm, 2.5mm, and 3mm.

What new spring clip are we going to need?

You guessed it right 2.5mm new spring clip will be needed to make 0.7mm clearance. Now the official spec. Gave us a range of 0.7mm to 1.0mm, so this one worked out fine. If the Spring-Clip does not make it you may have to increase the top steel to make that clearance, and the top and bottom steel are of different thickness, and based on that clutch pack the steels, and the end steels come in different thicknesses, and said FEW clutch packs have to be dead-on this minimum gap....

So one can look at the EPC parts for this transmission, or look at the WIT site for the clip and top steel for the given clutch pack

This is why we need a vernier-caliper to measure the Spring Clips, and Steel thicknesses

Hope it makes sense?

Martin
 

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#25 ·
The vin is WDBJF25H9XA871981

That does clear it up, I didn't realize you could change the spring clip size depending on the gap. But now It makes sense. I still don't understand the fill cycles completely but I haven't had a chance to read all of the literature you posted up on it yet.
 
#28 ·
Hey Jeremy,

Looking great, so I guess you found the bearing smoking gun. It looks like "Diesels" have a ball bearing K2... I see the K2 bearing in the hole, but what is that on the shaft? Bearing cage of some kind? or just an Imprint of the K2 bearing?

The Chrysler 722.6 service manual shows the image of the proper tool.


Looking good

Martin
 
#31 ·
No. 5 thrust brg. toast. Good, now that you know where they came from.





Now that's a good question. What are we seeing there?

Hey Jeremy,

Looking great, so I guess you found the bearing smoking gun. It looks like "Diesels" have a ball bearing K2... I see the K2 bearing in the hole, but what is that on the shaft? Bearing cage of some kind? or just an Imprint of the K2 bearing?

The Chrysler 722.6 service manual shows the image of the proper tool.


Looking good

Martin

Sorry guys that is just my bad photography the shaft is smooth, that is the reflection of the bearing on the shaft. There's nothing on the shaft itself. It was dark so I needed to use a flash. I'll get a better picture this weekend. When all of the drums come apart.

I actually wasn't sure if the bearing was bad or not, the reason being it looks like the needles that failed were evenly spaced so I thought maybe the bearing was supposed to be that way. Thanks for pointing it out. More pics to come.
 
#30 · (Edited)
I will upload the Mercedes EPC parts to YOUR specific transmission shortly to clarify what is on that mating shaft?

The outer rim of that thrust bearing area looks a little hot-lacking lubrication? I need to look at some of my pictures if it is normal? Maybe that is why the needle's fell-out?

Here are the parts sold by Mercedes per your vin, and many bearings are not sold separately as they sell the whole assembly..

Martin
 

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#32 ·
That thrust bearing is definitely bad; the question it raises is why. Too much end clearance? The usual reasons for a failed roller thrust bearing are too much load, too little lubrication, or too much clearance (rollers get "banged" instead of a steady pressure load).

I'm guessing this trans has been rebuilt, because AFAICT the roller K2 bearing (and mating shaft) were unavailable for 1999. I suppose it's possible that they made the upgrade as a running change and your VIN has the updated bearing & shaft, but that would be the first I've heard that a MY '99 shipped with the later parts.
 
#34 ·
My guess would be lubrication because as far as I know the trans had original fluid in it, or at least super old fluid when I changed it. How would we go about checking? Or is it just make sure that everything is tight when I put the trans back together?


If the trans has been rebuilt before are there going to be any other indicators we can use? If it's been rebuilt recentlyish then there's no point of doing another rebuild, just check everything fix what's broken and throw everything back together. The pilot bushing/electrical connector wasn't marked when I changed it. Would you guys be able to tell from the clutches?
 
#37 · (Edited)
- Being that it looks like the k2 carrier is upgraded are should I still change it or leave it as is? Also if the whole carrier is upgraded could that be what caused the thrust bearing to fail? Maybe the spacing isn't correct? Also the shaft that it sits on doesn't look like smooth wear? Is that ok or does that need to be replaced as well?
- Are the clutches good or do they need to be changed? (from looking at them I can't make heads or tails of if they're in good shape or not, the ridges don't seem worn, but the gap of the clutch packs is insanely off.
- Should I take the oil pump apart? There doesn't seem to be any issues but I found a crack in piston spring.
- How involved should I geet with the conductor plate. Currently I haven't taken it apart and wasn't planning on it. In an ideal world I would rebuild everything but for the sake of practicality (Remember guys I only paid $650 for the car) there are not shifting issues but if anything breaks on the plate it is simple enough to get to. I'd rather focus on the mandatory internals and spend less than $500 ideally less than $300.

***side note. I have a old digital camera in my garage that I used to take the pictures if you guys need better pics just let me know and i'll snap them with my phone which takes much better pics, I just didn't want to dirty it up while I was working****

Ring was already coming off when I took the clutches out -




[url=https://flic.kr/p/VbP6zG]

Is this normal (rear planetary)-


[url=https://flic.kr/p/VbPJiG]

The rear seal was on it's way out too -


[url=https://flic.kr/p/VnMv1b]


Here are some better pics of the shaft (it's a little easier when it's out of the tranmission housing -
[url=https://flic.kr/p/VbPH8A]

[url=https://flic.kr/p/VeJLVX]

[url=https://flic.kr/p/VcakQf]


Clutches -
K3 - (I think)
[url=https://flic.kr/p/VnM8bj]
[url=https://flic.kr/p/VnM8wE]


clutches in k2 -the teeth almost looked burned normal?

[url=https://flic.kr/p/VeJYP6]



Clutches off K2 drum (i think)

[url=https://flic.kr/p/VeJHRa]


Clutches off pump housing -

[url=https://flic.kr/p/VbP7H3]

K1 -
[url=https://flic.kr/p/Vf6pVi]

[url=https://flic.kr/p/URqmys]
 
#43 · (Edited)
So I took the pump apart yesterday there seems to be a little bit of scoring on the gear and on the housing not. Also not sure if this is how it's supposed to be that way. Also the bearing housing looks like wear, not sure if that's normal -



wear of the housing -



Back of the gear -



Took the filter apart just to see if there's anything on the inside. Pretty clean -



I know I said I was going to leave the conductor plate alone but I decided to check the springs (Didn't take pics of front)





The small gaskets are failing too -




I'm ordering the parts today. So everything should be going back together next weekend.
 
#51 ·
I noticed you changed your hosting of pictures because I could not click on the pictures like before. Maybe upload the scaring of the bell picture and the front of the pump like you had.

The pump is no biggie. I have a few I can sell you(with the gear). I would not use that gear(and main pump), but shot a picture of the outline of the bell maybe it is identical to the M112/m113 because I got some of those too. The Mercedes new bell is about $500 to $600. What some shops do is mill it down 0.001" to 002". Like I said I have never done a Diesel. If the bell is only to a Diesel(Actually I'm going to compare the EPC from your car to my M112 E320 to see if they are the same), then the solution is find a local machine shop in your area that can do the fine milling(again looking at your revised picture), but I understand SunValley Transmission in California mill these, so that may be option?

How is play on the rear bearing on the housing?

I wonder if you have a pre-2000 valve body? It has a regulation spring? The +2000 valve bodies have improved lubrication, and your problem with the pump is lubrication. This pump problem is verryyy common on the 722.9, but 722.6 it is rare, yet I have seen it on another 722.6, yet my theory is the result of the low torque value of those pump bolts being held inside. That is why I double clean all bolt holes with denatured alcohol. Use high vibration/high temp LocTite (it is not the stuff at the auto parts store-That stuff is super lame). I torque the bolts 50% to 100% more as I saw one person had them back out, and had what you have(burned bushing/burned pump). Maybe this has been the problem with the 722.9's as the first symptom is leaking fluid from the bell the the crunching of gears later in time, but who knows....

Martin
 
#55 ·
I noticed you changed your hosting of pictures because I could not click on the pictures like before. Maybe upload the scaring of the bell picture and the front of the pump like you had.

The pump is no biggie. I have a few I can sell you(with the gear). I would not use that gear(and main pump), but shot a picture of the outline of the bell maybe it is identical to the M112/m113 because I got some of those too. The Mercedes new bell is about $500 to $600. What some shops do is mill it down 0.001" to 002". Like I said I have never done a Diesel. If the bell is only to a Diesel(Actually I'm going to compare the EPC from your car to my M112 E320 to see if they are the same), then the solution is find a local machine shop in your area that can do the fine milling(again looking at your revised picture), but I understand SunValley Transmission in California mill these, so that may be option?



Martin
I changed the pictures so that you should be able to click on the bell housing. I'll changed the other ones as well. I'd be interested in buying the pump. So your conclusion is that there is no way I should reuse the bell either? There is a metal shop around my house I'll I can ask them but I'd rather avoid it at possible.

I'll get better pics of the bell housing and I can get you the Benz number. But the number I have on the housing (not sure if this is for the trans or the housing specifically -



If you have one that fits then I'll be happy to take it off your hands. :grin

I'll check the bearing play and the valve body tonight and get back to you. I'm very hazy on how the valve body works so I don't know how much help I'd be. I'm wondering if the root cause of the poor lubrication be that the trans fluid was never changed?
 
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