1984 300D Trans Rear Main Seal, anything else?

[earthblues]

Hello Everyone 1984 Mercedes 300D TurboDiesel 389,000 Miles

I have a transmission leak, cleaned underneath the tranny and have
no doubt that it is the Front Tranny Seal of the Transmission, could be the original.

QUESTION:
While the transmission is taken out to replace the Front Tranny Seal,
what else should I replace in that area?

After researching this forum, I think I will replace the Rear Main Engine
Seal ...

Should I replace the Ring Gear (aka Flywheel Ring)? Rear Tranny Seal? Torque Converter and Seals? Anything else related to the Transmission?


WORK DONE IN THAT AREA AND WHEN:
Mileage 385108 12/22/08 until 1/6/09
Engine shocks, Engine shock mounting kits, Rear Transmission Mount, Tranmission Vacuum Modulator Valve, Transmission Filter Kit

Mileage 386327 3/9/09 until 3/23/09
Transmission Output Seal, Transmission Output Flange Nut, Flex Discs, Bearing Dust Cover, Pilot Support Bearing, Drive Shaft Support, Differential Input Flange Nut, Differential Pinion Seal


I look forward to reading the responses!

If you have an original tranny with almost 400k miles, replace it with a rebuilt.

[junqueyardjim]

I believe the rear seal is a "rope" seal and I think you can put the lower half in by pulling the main oil pan, (when the engine is out of the vehicle), but I think the crank has to be removed to put in the top half. Some of these jobs are pretty mean. The torque convertor flywheel if it is not broken or really worn out I would leave it also.

[Hit Man X]

Replace the reverse clutch pack. Reseal the rest of the trans while it is out... NOT hard. New NSS, they are a PITA to do in car.

[Stretch]

FYI OM617 rear crankshaft seal =>

http://www.peachparts.com/shopforum/showthread.php?t=288644

[earthblues]

CRAIG Thank you for your reply, I don't have the money for a rebuilt transmission now, so I will have to do second best, I will certainly keep your advice in mind.

JUNQUEYARDJIM That does sound pretty mean. I will have a look in that area when the Transmission is pulled. I will check out the torque convertor flywheel to see if its worn or broken. Thank you for your time.

HIT MAN X Thank you for your response, I have some questions for you when you have the time....

1) "Replace the reverse clutch pack" I was looking through Phil's online catalog, and I cannot find a "reverse clutch pack" in the transmission section, also tried a general search.... Is it called something else?


2) "Reseal the rest of the trans while it is out" Please tell me which seals are involved to do that. Would this include the Rear Tranny Seal? and if there are other seals involved, please tell me the specific ones.


3) Is NSS the "Neutral Safety Switch"?
Thankfully, I replaced that at Mileage 385108 on 01/06/09, in car, but had to do it, it rolled in
"Park".


ARMY Thank you very much for your "OM617 rear crankshaft seal" thread, I will have a look in that area when the Transmission is pulled.

[Stretch]

Originally Posted by earthblues

...
1) "Replace the reverse clutch pack" I was looking through Phil's online catalog, and I cannot find a "reverse clutch pack" in the transmission section, also tried a general search.... Is it called something else?


2) "Reseal the rest of the trans while it is out" Please tell me which seals are involved to do that. Would this include the Rear Tranny Seal? and if there are other seals involved, please tell me the specific ones.
...

Replace the reverse clutch pack - hmm I'm not sure what was meant but to the best of my knowledge the 722.1, 722.2 and 722.3 transmissions rely on a freewheel brake (towards the rear end of the box) and the middle brake band (B3). I don't think that this is likely to be needed if you are tackling leaks.

To reseal the transmission properly you need to strip it down to its component parts and then rebuild it. There are seals on the inside that can leak too. If you want to replace some of the outer seals then fine - but look out - sometimes these things tend to get out of hand. You could start by doing a simple seal change but end up rebuilding it.

I'm in the process of a 722.1 rebuild at the moment. I plan to write it up when I've finished - but so far I can say you are going to spend more money by buying a complete reseal kit than by specifying particular seals. The problem I had was finding anyone who would sell me seals individually... I ended up buying a kit that contains every seal for every version of a 722.1 transmission: Pain in the arse.

If you want to see what is involved in a transmission rebuild take a look at these exploded parts diagrams:-

722.0, 722.1 and 722.2
http://www.ganzeboom.net/images1/ganzeboom/parts/Mercedes/722.0,%20722.1,%20722.2.pdf

and for the 722.3 and 722.4

http://www.ganzeboom.net/images1/ganzeboom/parts/Mercedes/722.3,%20722.4.pdf

[starrywhite]

I'm butting into some heavy conversations here
I have just put new transmission fluid into my 1979 300 TD
THere was evidemce of minimal atf leaking underneath the torque converter before I did the change, but since then it has been leaking steadily by a tablespoon per day.
I was very careful not to overfill.

Do you think the torque converter seal has gone and it's time to pull the transmission?

[Hit Man X]

The reverse clutches are known to be the weak part of the .3 trans. They wear easily for some reason. They are known as the 'B3' there are four of them from what I can remember. They are right behind the pump.

http://www.bulkpart.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=2&Category_Code=722-3 All sorts of 722.3 parts

http://www.bulkpart.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=2&Product_Code=68110B&Category_Code=722-3clutch

The .1 is setup differently to engage reverse.



The rest of the seals I refer to are such as the input seal, pump pushing, servo seals, TV cable o-ring, rear seal, etc. All of the usual suspects for external leaks. I do not mean replace the o-rings on the inside.

Most of the leaks on my cars are from the pump/input seal.

[Stretch]

Originally Posted by starrywhite

I'm butting into some heavy conversations here
I have just put new transmission fluid into my 1979 300 TD
THere was evidemce of minimal atf leaking underneath the torque converter before I did the change, but since then it has been leaking steadily by a tablespoon per day.
I was very careful not to overfill.

Do you think the torque converter seal has gone and it's time to pull the transmission?

First thing I'd do is check to make sure the torque converter drain plug is tight.

[Stretch]

Originally Posted by Hit Man X

The reverse clutches are known to be the weak part of the .3 trans. They wear easily for some reason. They are known as the 'B3' there are four of them from what I can remember. They are right behind the pump.

http://www.bulkpart.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=2&Category_Code=722-3 All sorts of 722.3 parts

http://www.bulkpart.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=2&Product_Code=68110B&Category_Code=722-3clutch

The .1 is setup differently to engage reverse.



The rest of the seals I refer to are such as the input seal, pump pushing, servo seals, TV cable o-ring, rear seal, etc. All of the usual suspects for external leaks. I do not mean replace the o-rings on the inside.

Most of the leaks on my cars are from the pump/input seal.

Ah ha - close inspection of the 722.3 pdf I posted shows the B3 / reverse clutch on page 2 of the PDF. It looks like (from this picture) that there are a set of 5 clutches there.

I checked the 722.3 ATSG manual before posting my previous comments. At the front of the manual there's information concerning how each part of the transmission works for each gear selected. I'm guessing they've just copied the information in the 722.1 manual and been done with it as it doesn't mention this "extra" clutch at the front in that part of the book...

[earthblues]

I apologise for the late response. My Transmission is a 722.3

ARMY
Thank you for the Transmission Rebuild Exploded Diagrams, obviously this is very involved,
you really have to know what you're doing. Thank you for your time on this post!

HIT MAN X
"The reverse clutches are known to be the weak part of the .3 trans. They wear easily for some reason.
They are known as the 'B3' there are four of them from what I can remember. They are right behind
the pump."

"The rest of the seals I refer to are such as the input seal, pump pushing, servo seals,
TV cable o-ring, rear seal, etc. All of the usual suspects for external leaks. I do not mean
replace the o-rings on the inside."


QUESTIONS FOR HIT MAN X:
1) In regards to the B3 Reverse Clutches, could this be the source of a "chatter" sound that
hear when I accelerate the vehicle in reverse?

2) In regards to the rest of the seals, please clarify:

"Transmission Input Seal" - Did you mean the Transmission Output Seal? Is this the seal that require
the 30mm, 12 Point Extra Deep Socket to get to? I hope so, I replaced that at Mileage 386327 on 3/9/09.

"pump pushing" - Did you mean Transmission Pump Bushing? If so, understood, will replace.

"servo seals" What is this?

"TV cable o-ring" What is this?

"rear seal" Understood, will replace.

Thank You Hit Man X, I look forward to your reply!

[Hit Man X]

The chatter could be extremely work reverse pack. Apparently the basket bottoms out in the case. Mine is not this bad yet, if yours is... stop using reverse. Park so you can pull through or roll backwards from spots.

No, not the output seal. There are two up front... a pump bushing and a front pump seal. These cause the majority of the leaks. Most are not fixed as they require trans removal which is just a PITA.

The servo is just a piston (there are two), they have seals internally and externally. Think large o-rings.

I think the Bowden cable is the proper name, I am just accustomed to TV cable (throttle valve) for my Ford's AOD and the old 200-4R from GM. There is a small seal there too.



The thing is out and on the bench, no better time than now to just reseal all external rubber seals. If this truly is an original 400k trans, you may as well just replace all friction surfaces internally too.