capthook

Ok, i'm posting this over @ benzworld.org ; but thought it might be a good idea to post here as well since the problem is transmission related and it can get complicated for us DIY'ers. Anyway, lost power in all fwd gears coming around a corner at 15mph - stepped on the gas, and nadda. Heard nothing go 'clonk' or 'bang' so I posted over @ benzworld and some one suggested I investigate the B2 piston (operates lower gears), well my tranny was rebuilt about 3-4 yrs ago by the previous owner and it appears I have the new B2 gear with plastic surround. It was intact, but another part fell out when I took it out:

??? part that fell out


The B2 Piston



Any ideas on what this part is that fell out when I took out the B2 piston?

Fluid looked A+ ; no burnt smell - no debris - just this part popped out. Car shifted fine before, no problems.

C32AMG/02

That pin applies the B2 band, inserts into the B2 piston and pushes on the band. If your transmission is a 722.4 you have a broken B2 band, no movement. Remove the valve body and check the B2 band.

capthook

That pin applies the B2 band, inserts into the B2 piston and pushes on the band. If your transmission is a 722.4 you have a broken B2 band, no movement. Remove the valve body and check the B2 band.

First of all, thanks for the reply. Ok, i'm totally clueless when it comes to our transmissions. I have a '90 300e. How do I find out what my transmission model # is? Also how do I remove the valve body ... I assume this is the next thing in line , before the b2 band?

Can you remove / replace the b2 band with the transmission in place or will I have to completely remove the tranny?

Thanks in advance

C32AMG/02

If your 300e has a 2.6 engine it’s a 722.4, if the band is broken, transmission most be remove. The valve body is in the oil pan.

capthook

Ok, the valve body can be removed easily? With just the bolts that hold it; or is there a line i need to disconnect...

Also what should I check for once the valve body is removed. Where is the band located, as well as the thrust element. I've [never] worked on an automatic tranny, and [hopefully] never will again!

My only hope is that I figure this out so I can save myself some cash knowing what it is that needs done.

shdoug

YOU are an extremely brave man. I consider myself to be way above average for an amateur mechanic, but I would never attempt to tear into an automatic transmission. Let us know how it turns out.

124-Fan

Yes, this pin engages the B2 band. I just recently replaced this pin in my transmission (722.346), in order to adjust the freeplay in the band. It is possible to replace it without removing the transmission. You must remove the valve body and the intermediate plate. Then you have to undo the transfer mounting and lower its rear end in order to gain access to the piston. It´s a bit tight, but possible.

The band might be broken, but not necessarily. If there was too much freeplay before, the pin might just have slipped out. If that is the case, I recommend installing a longer pin. They are available in 5 or 6 lenghts. They are marked with lines, which indicate the length of the pin.

The freeplay in the band is adjusted so, that the band is firmly aligned with the K2 carrier, without contacting it. Freeplay shouldn´t be more than 1-2 mm.
-But if you haven´t worked on a transmission before, I recommend you have it done for you..
Cheers,

capthook

Yes, i'm either brave -- or stupid for trying this ; i did get the b2 piston out myself though which apparently isn't very easy with the tranny in the car. It wasn't for me.. it's a very tight fit in a w124. I had to use wood blocks to move the tranny to the left, then removed (2) mounts which lowers the rear drive line and the one just below the transmission. I don't even want to attempt to put the B2 piston back in myself, the thought of it makes me cringe the fit was so tight.

Anyway, thanks for all of your advice - I will take off the valve body and such today in an attempt to locate the source of the problem : i.e, broken parts ; but i don't think i'll try repairing it or putting the push rod in with the b2 piston - since my knowledge of transmissions is minimal at best. I do know you can use vaseline to keep that pin in place - should i try to put it back together. BUT.... I'm just trying to locate the source of the problem without mucking anything up : keeping the parts all completely clean during this process is the hardest part - but trust me it's being done.

Everything so far has looked super clean (no debris, fluid looks new) as this transmission was rebuilt 3-4 years ago - so i'm still looking for the culprit. All fails, I'll take her to an indy transmission shop and have them overhaul it but I would like to know specifically what the problem is before I go about throwing money at transmission people -- I'm sure you guys know what I mean there! All u hear from them is : "uhhh, we'll have to rebuild it". Even though the B2 piston / band problem is very common on the pre-94 mbzs

On the pin slipping out note - yep that could be a possibility since I didn't hear it drop when I popped off the cover, the cover didn't (spring out) quickly when it was attached - and it was just laying there behind the b2 piston. Plus I really haven't seen any other broken parts / metal in my pan etc... so that could be a possibility

capthook

Well, thanks for your guys' help - took off the Valve Body and the other one & it turns out it's a broken B2 band (I think) or is this pieces of the thrust element?

124-Fan

This is the B2 brake band that is broken. The thrust element is what holds the band in place, on the opposite side of the B2 piston.

This won´t be remedied without tearing the transmission apart, I´m afraid. Sorry man. - But these transmissions are nice and easy to work on, although if you have it rebuilt for you, you might get ready to pay a few bucks..

I would replace all the discs and seals while I´m at it, because in order to replace this band you must tear it apart completely. It rests in the rear end of the transmission.

Cheers,

capthook

Great... not what I wanted to hear, but at least I know what the problem is now. Thanks 124-fan Anyone have the part # for the b2 brake band? I just got quoted $360.00 for the part from the dealer

124-Fan

The number for B2 brake band is: A 126 270 20 62

Cheers,

capthook

Thanks, it's $220 over at Autohaus AZ. Once the transmission is out, do you have to take the entire thing down to replace this piece I might be in way over my head here. LoL I found a car with another transmission (93 300e) 120k mi. What's the average (200k?) these w124 transmissions are good for - or should I seriously try and replace the AT brake band myself?

shdoug

How long they last seems to be directly related to how often the fluid was changed. They recommend every 30,000 miles. You know most Americans' attitude toward transmission fluid changes: If it ain't broke, don't change it. I've heard they will last over 200,000 miles, but a poorly maintained one will give out before 100,000. Mine had 162,000 and reverse was getting slow so it would not have made it much further. The previous owner let the fluid get "very dirty" so that was probably the cause.

A coworker of mine has a Ranger with 95,000 miles that the fluid was never changed in and the tranny is on its last leg. He doesn't think it has anything to do with the fluid because it doesn't look burnt. Even my company believes in never changing the fluid in the fleet vehicles, and they usually get just over 100,000 miles on a transmission. After owning the W124, I'm a firm believer in regular fluid changes. But someone here will say I'm crazy for sure.

capthook

Makes sense, i guess it's all in how it's been serviced. Fortunately - Bay Area Benz's tend to be dealership kitties. It does all depend on the owner though, and these cars aren't getting any younger. But, damn it I love my w124 and want to keep it for as long as I can, it's such a well built tank !

Just wish it was a tad easier to do this. The thought of doing an overhaul job on my transmission kinda scares the crap out me ; but at the same time I know what I have has already been rebuilt so I dunno...

Right now, this is where she's at . Damn it's painful - I want to drive her!



Anyone have w124 transmission removal instructions? I don't have the CD / service manual for the 300e anywhere

124-Fan

Your car looks nice !
-But using these facilities, I don´t recommend removing the transmission, even though removing it isn´t very hard, when upon a lift. -Undo the prop shaft and heat shields. Then the housing bolts and the converter bolts from the flywheel. You must also lower the exhaust system, or even remove it if that suits you better. Then disconnect the vacuum hoses and cables.

I don´t either recommend that you overhaul the transmission yourself, since you are not familiar with these things. But then again, it isn´t very complicated even though you must do it the correct way and be sure of what you are doing.

Cheers,

capthook

Thanks again w124 fan.. I don't think i'll attempt to overhaul the transmission - I might after I have another one in and the old one out though - just to be on the safe side ; having 2 working trannies is better than one. And yeah, I don't really want to drop it in my driveway, the clearance isn't fantastic - but I don't know anyone with a lift I may end up paying a shop to do the swap - we'll see. For now I've had my taste of transmission fluid , and I think I am all good for a long time

C32AMG/02

Great Job, Can you post the 722. #### Number located on the passenger side, middle of the transmission pan rail, were the pan bolts too the case.

capthook

Here are the numbers on the transmission:

124 270 88 01
722 358 0 3385855

Engine is a 3.0L. Thanks again, C32AMG;

Does anyone know what years / models swap over into the w124 3.0 L ? The 722.358 that is... I found a 2.6L ; 190 the other day with 100k ; but I think the tranny's are different for the 2.6L. I also found a 93 300e (120k mi) but I think it's the 722.369 for '93's ; not the .358 like in my '90 .

On a wishful note, I found this 255hp 3.6 L RennTech this guy is selling here in the bay area locally:

http://cgi.ebay.com/ebaymotors/ws/eB...ksid=p3907.m29

But I think it's kinda overpriced, myself with a starting bid of $3,300 . Can't afford it anyway but it's a definitely a cool thought - Capt

P.S. - answered my transmission swap question with this link:

http://www.europeantransmissions.com/Application.htm

...but i'm still a little confused. From this link, it shows that the 722.358 is only found in '91 & '92 300e's with the 3.0. But the '90 (my year) shows 722.320 , not 722.358. Is that correct? I can't swap a 90 for a 93 transmission is what this is looking like.

124-Fan

Usually, with w124 and other older Mercs, you can´t replace a transmission with another one if it comes from a car with a smaller engine. That´s because there is different working pressure in the valve body, which can lead to clutch slippage and loss of performance when a transmission is installed in a car with a bigger engine than the transmission was designed for.

But in the 3.0L w124´s, the transmissions are all interchangeable although there is a number of variations and upgrades. Refinements were made on the valve body, a secondary oil pump was removed and shift quality improved during the years of production. A transmission from a ´93 model 3.0L car will fit your car nicely, although if I remember correctly, you might have to replace the bowden cable as a result of a different attachment to the transmission housing. Not sure though.

The different numbers you speak of, found in the 3.0L car, simply mean that that these are all transmission of the 722.3## class, but manufacured at a different time, and with different internal upgrades for improved quality and durability.

Cheers,

capthook

Thanks, great information ; I can't believe how much you guys know
So it seems I can swap this 722.358 with (any) 3.0L 300e series transmission and that's kind of a relief.

124-Fan

Yes but be advised, that some cars were labeled as 300, and still having a 2.6 litre engine or a 3.2 litre engine.
-Not sure transmissions from that cars will work. It must be from a car with the 3.0L M103 engine.

Cheers,

YNVDIZW124

If I was in that situation I would buy a used transmission from wrecked car with light front end damage. The good thing is that insurance companies will rather call our cars a "total loss" for a fender bender because it's easier to pay 3k for the car than 5k for a new paint job. If wouldn't get a new transmission because i'm sure i'm not going to keep the car for another 10 years. It all depends on how much the car is worth and how much a new transmission costs. I do agree transmission fluid/filter changes are a must on these cars. I change mine every 2 years.

those are my .02c...

capthook

Right on, thanks again guys. I got a quote for $1,100 to put a new band / seals / do an overhaul on her, so I'm not quite sure paying $300 for a used tranny + $500 for the install is better than just paying to have it overhauled...

capthook

So, this is likely a dumb question - since I think only 722.3xx series transmissions will work with this 3.0L 300e ; but I found a great condition, wrecked '95 c280 : transmission is 722.424 - is this a remote possibility?