Transmission Problem & Fix
 

While driving home, doing at least 70 mph, my transmission went out. Nothing, nada, ziltch. Got a tow home.

Most folks said the trans was just shot.

I got a call late night from one of the moderators of the forum who told me to look at the end of the transmission and a possible loose nut.

That was it!!!

The nut came loose and the drive-shaft shifted backward.

When I started to take the thing apart, you could rattle the nut around with your finger.
The splined yoke is shot.
The nut is shot.
While taking it apart, the flex disks were on their last leg also.
As for safety issues, 2 out of six bolts were very loose, one was missing, and one was almost cut in half.

So, if your ever driving along and your transmission goes out completely, take a look at the back of your transmission for this nut and the splined yoke.
The moderator is my hero of the month as I was starting the process to yank the transmission!
Does anyone know the technical name for this part and nut?
Does anyone have a good one for sale with the nut?
I understand the nut is upgraded so you don't have to buy the special MB socket.

You need to tell us what car and transmission as there are several yokes.

A moderator called you? How's that for service? :D

Sixto
87 300D

Sorry --

The car is a 1985 MB, 300D Turbo, W123.133, Engine is a OM617-952, Trans is 722.XXX (not sure exactly).

does have 6 bolts in the pan? what color is the modulator?

I bet it will be a 722.303 or a 722.315 - probably the last one. To check this, look down the side of the gearbox casing just above the oil pan on the right hand side of the car.

With regards to the nut - I spoke with the dealer yesterday about one and they said there is only one number for the nut. So it doesn't seem as though it has been upgraded officially. I'm getting in touch with a transmission rebuilder today to see if it is an unofficial mod!

EDIT:-

I just spoke with the transmission builder and the nut is used for newer transmissions too - it is a 12 sided nut. It costs 3,40 euro excluding taxes over here.

more info please
 

Hey Army, et al

Did you get the part number on that nut ? Can one get this in the USA? Also, I am pretty sure my transmission is 722.315. That was stock for this car. As for the pan, yes, it has 6 bolts, 3 on each side of the pan. Please let me know. Thanks !!!!

Sorry I don't have a MB part number as yet 'cos they've told me that that one has the stooopid 2 pin set up which would mean I'd have to buy (yet another) special tool => or spend yet more time making one.

I've gone for the after market version.

You can see it on the second page of this pdf file number 798

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

EDIT:-

I'm sure it will be cheaper and more widely available (perversely) in America than it is in Europe!

Ask the sponsors of this site. I'm sure they can get one. If not do an internet search for "Mercedes 722.3 parts" you'll get several possibilities - even ebay if you can be bothered to search through all the junk to find it.

Answer
 

I was happy to help you. :D

Attention, EPC has a typographical error on the upgraded 722.xxx transmission output flange part number...
The correct available part is.


Output flange, 722.3/4 transmission
MB# 202 272 00 45
http://www.pelicanparts.com/cgi-bin/ksearch/pel_search.cgi?SUPERCAT_FLAG=Y&make=&please_wait=N&forumid=&threadid=&command=DWsearch&description=2 02+272+00+45&I1.x=12&I1.y=11
722.xxx transmission output flange 90 MM.
Application list: 722.300, 301, 303, 304, 306, 307, 308, 309, 315, 319, 320, 322, 351, 358, 400, 401, 403, 404, 405, 406, 407, 408, 409,410, 411, 413, 414, 415, 416, 417, 418, 420, 421, 422, 423, 425, 426, 427, 428, 431, 434, 435, 438, 440, 441, 442, 443


Nut, 722.xxx transmission output flange
MB# 123 990 00 60
http://www.pelicanparts.com/cgi-bin/ksearch/pel_search.cgi?SUPERCAT_FLAG=Y&make=&please_wait=N&forumid=&threadid=&command=DWsearch&description=1 23+990+00+60&I1.x=10&I1.y=5



.
http://i21.photobucket.com/albums/b2...ve_1_yqmaf.jpg
http://i21.photobucket.com/albums/b2...ve_2_yqmaf.jpg


.

New Parts and the Car is up-and-running
 

After 3 weeks, all parts arrived. I got 2 flex disk kits, transmission output flange & nut, and new driveshaft (upgraded/modified as it now has grease fittings.) Here are some pictures. For almost $650.00, it runs silky smooth now. Not sure I got the flex disks on correctly. The bolts and nuts were odd, needed 6 point hex and a lot of muscle to tighten. I guess they were designed to go on with a lot of torque so that they would not loosen? I doubt all 12 of the nuts - bolts were somehow screwed up in both kits.
As for the helpful moderator, again, thanks. No more walking to back and forth to work, bumming rides, and with the heat at 99F nights, this was a real life saver. Next project -- get my A/C fixed !!!

That's the best kind, for sure!!!

Hmm
 

This looks to be the same issue.

http://www.peachparts.com/shopforum/diesel-discussion/332017-did-i-kill-my-transmission.html

.

Another good example of why its not a bad idea to have a car up on a lift/hoist from time to time and inspect everything.

FYI
 

Here is the issue again, with an odd cause..
http://www.peachparts.com/shopforum/tech-help/332084-190e-w201-does-not-move.html#post3068737


.

The California-edition of the 300 D/C/TD Turbo came with a 722.4 transmission in 1985.

The nuts on the flex disc bolts are ovaled lock nuts intended to screw on tight the whole way.

What an interesting post! In my case, I was towing a parts Mercedes up some serious BC mountains, and my friend behind me was following in the Merc that was supposed to be good.

Halfway whilst following me, he realized that his transmission was shot, because the car was starting to move BACKWARD on the hill!! :eek:

We quickly realized that the car can shift and reverse, but no forward motion was possible in any gear. I think what killed it was the following of my vehicle towing the heavy merc up the mountains at my towing speed. Perhaps he would've saved the transmission if he had speeded up and just gone ahead of me.

The car is all fixed up now, just bodywork, but we had to replace that transmission with a rebuilt.

Search on B2 piston.

FYI
 

This may help other members searching for B2 data.
http://www.peachparts.com/shopforum/diy-links-parts-category/142395-transmission.html



.

Bump
 

for customer with this issue.

.

Same thing happened on my 92 500SL (R129)
The nut came loose, then of course lost engagement with the tranny then towed it home
It chewed up the inside splines on the output flange real well
Fortunately the tranny was still under warranty (installed last year)
and they're going to ship me another flange free

https://lh6.googleusercontent.com/k1...4=w939-h626-no
https://lh4.googleusercontent.com/-5...o/DSC00382.JPG

At first it was real hard to find
Thinking I would have to find someone parting out a 90-92 500SL (I think they changed back to a 3 point in later models (?))
Since looking at a 93 parts schematic
http://www.mbpartsworld.com/showAssembly.aspx?ukey_assembly=1094780&ukey_product=7934758

A few transmission places I called only had the 3 point flanges

The part number I found for the 92 is 1292720445 which sells for about $120 at most places

ECS Tuning sells theirs for $95
http://www.ecstuning.com/ES1669873/
http://c1552172.r72.cf0.rackcdn.com/174593_x600.jpg

Sun Valley sent me another flange and nut
I used loctite just to be sure that sucker didn't come off again :D

Recycled
 

For new owners.
.

Happened to me one day a few years ago. Backed out of the driveway, put it in drive and the engine revved up going nowhere. I shifted between the gears and the transmission could be heard engaging. Put it in park and the car still rolled. I set the parking brake, reached under the car and slammed the drive shaft back into place and pulled back into the driveway. I was upset at first but a quick process of elimination narrowed me down to the driveshaft connection.

So just wondering,i recently bought a 1981 307d. Would this vehicle suffer the same fate as these cars,i know its a 616 engine but did they strengthen the trans output shafts and diffs based on the added workload and towing requirements of a commercial van? cheers

The 722.3 series is a plenty strong enough transmission. The issue I have seen is that someone has "played" with the output shaft nut. Typically they don't get torqued to spec, reused or not peened properly. All 3 scenarios in my situation. I found an updated bolt design, peened on two sides and half-ass peened at that, plus the obvious torque not being applied. Done properly, the nut should never back off.