722.118 Transmission problems, stripped out splines!
 

I have an 1981 300D with a 722.118 automatic transmission, just under 188,000 miles. I was wondering if anyone else has ever encountered this problem...

The previous owner stated that when pulling away from a stop one day, she heard a clunk noise and then had no more power being transmitted through the transmission. Moving the gear selector had no effect what so ever so she had it towed to her shop. They told her it was most likely internal damage so she decided to sell the car.

I bought the car from her, checked the car over, and found that the trans fluid was a little dirty but it did not smell burnt and the level was correct. I then took the transmission out of the car, took it apart and this is what I found...http://img849.imageshack.us/i/frontplanetmissingsplin.jpg

So that's why the car wouldn't move! This is the front planet gear assembly and the splines that are stripped out connect to the intermediate shaft.

The intermediate shaft splines look ok so I would like to find just a front planet if at all possible. Does anyone know of any transmission disassemblers that would have something like this? Has anyone else even seen this? Honestly I don't know how an 88hp diesel could rip those splines out, unless the previous owner was doing full throttle neutral drops!

At any rate I will take the transmission apart to clean the metal out of it and check the rest of it over. If anyone has any experience with this type of failure, your input would be greatly appreciated. Thank you.

still no pictures. Still sounds nasty though.

Wow that sounds like fun

I'm in the middle of stripping my 722.118 apart at the moment so if you need any comparison pictures let me know.

The damage you've posted on the pictures isn't all that clear to me but I kind of see what you mean I think... I'm going to go and have a look at mine in a bit.

As for parts - well so far I've been struggling finding anything for a reasonable price.

I've been using this parts diagram for pulling bits apart. I hope it is of use:-

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

My 84 300D transmission is all apart. (case bad) you are welcome to the planetaries if they will fit.
call roy, and verify.

I have NEVER seen this happen.

Wow!

Were they pulling a trailer or something????? Or, perhaps a neutral-drop technique????

Could it have been on a dynamometer for an emissions test or something, running at 65 mph and came of. The abrupt load on the drivetrain would probably cause something to fail.

Thank you Army for the diagram, that will certainly be useful when it goes back together.

vstech, what is the transmission model number for your 300D? I do not know who this Roy is that you are referring to, is he a member on this site? If so how would I go about calling him? Can you PM me his info?

From the few people I have called today looking for this part I haven't found anyone who has one yet.

The only thing I can think of that would cause this is having a maladjusted transmission that shifts harshly for a long period of time. The planet carrier looks to be some sort of cast iron or steel, so impact strength is not its strong suit.

After talking to a Mercedes dismantler today, this apparently is a common failure for these transmissions, so how long will a replacement last I wonder? Only one way to find out! The search continues...

I've only been here for a short while too - I don't know everyone's real names yet but I think Roy is whunter - chief peach parts guru / moderator etc etc

You could try calling the sponsors of this site to see if they know where to get the part otherwise you could try emailing the people here in Holland who have that pdf file I provided in my last post.

On a hunch I'd go along with Doktor Bert instead of the dismantler - but even so the 722.3 transmission is generally thought to be stronger...

I'm finding out the hard way that these transmissions have some seriously expensive parts in them. Send vstech (John <= See I know that one!) a personal message (PM) and see if he has the correct bit for you.

How are you getting on?
 

Have you found the bit yet?

Here's a picture of mine => you can also see wear at the same place...

http://www.peachparts.com/shopforum/...1&d=1304069909

Could it be that persistent low vacuum would cause this damage thru harsh upshifts and downshifts over a long period of time?

It could very well be that; this splined shaft is always under load from the torque converter (well when the engine is running anyway) and it is also subjected to "backwards" forces coming back through the gearbox from the driven wheels.

Every time something rough happens be it a hard shift / slamming the gearbox into reverse whilst the car is moving forward, I guess this flimsy looking splined shaft would feel it all.

Edit:-

I did add in a bit about "smacking the gearbox into park without applying the brakes and letting the car wobble 1970s springy-American-car-style" this is incorrect - all of the force would probably end up on the park pawl at the back of the gearbox. I think all of the clutches and brake bands would be disengaged so this splined shaft would not feel that effect. I'm going to check this in the manual though...

722.118 trans
 

see my reply to army under 722.118

That's kind neubob

Follow the link:-

http://www.peachparts.com/shopforum/2708893-post12.html

I've been doing a little bit more detective work for this part. I've found that none of the companies I know of in the UK or the Netherlands can supply this part. The dealer says it isn't in stock but might be available via the "old timer center" (probably in Germany) on special order => which means they might build it for you.

Thank you everyone with your replies. I have decided against fixing this transmission since it looks like if I do find a replacement planetary, it will be just as weak as the one that was originally installed at the factory.

I'm leaning now towards putting a manual transmission in the car, since I like driving those more anyway. So if anyone wants a partially disassembled 722.118 transmission, feel free to send me a message.

I will also try to make an add up for the classified section, but since I have less than 10 posts, it may get taken down (I'd much rather read other peoples posts than write my own :D). We shall see. Again thank you all.