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Discussion Starter #1
I thought it was the B2 piston. I was wrong, the transmission is dead. I cannot afford the 2500 dollars it would cost to install a new(er) transmission. I am going to law school next year and can only take out so many loans.

I bought this car last June from a born-again, ex-heroin addict, ex-con preacher from New York. I'm serious. He even gave me a signed copy of his book. I bought this car for $2100 and a sermon. As far as I know, the trans is the only major thing wrong with the car. It does have some rust spots and a few cosmetic blemishes I was going to take care of when the weather became warmer. The tires are 2 weeks old. Literally, I bought 80,000 mile tires and then had the ball joints and bearings replaced in the front. Then I filled it up with diesel. Then it breaks down. This would be a great car for someone who has the time, money and garage space to do it justice. Or, a tear in my eye as I write, someone who wants to part it out The shop also said they found a tranny with 88,000 miles on it, and can provide you with the info on that if you wish.

I will provide pictures when I get the car back from the shop. Until then, I can answer any questions you have at [email protected] I trust the people in this forum know what the car is worth, so I will entertain all offers.

1985 300d Turbo, 203,000 Miles, gunmetal blue, tan interior.

Thanks.

The Bryant
 

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1988 560 SL
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Sorry to hear about your tranny. It just seems strange that you had no warning,slippage noise or any symptom of a problem. I assume the person who condemed the trans was a trusted mechanic? The reason I say that is that I bought a car once from a relative who said the car needeed a trans (a mechanic told him $1500 to repair) when all it needed was a cleaning.(everything was gummed up). This car would not go forward or backward,nothing.I hope you can resolve this without taking such a financial hit.
John
 

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1984 300D Turbo
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i find it also hard to blv that the trans is 'dead' at 203k miles. did you try pulling all the vacuum lines off the leak valve on the IP? ie let no vaccuum gets to to the trans? the shifts should be all firm.
also you could try 'trans-x' - to clean out the trans. i
have heard this can revive what people thought to be 'dead' trannys.
i would not give up yet.. it may be something simple.
 

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Discussion Starter #4
I don't know. I took it to a reputaple(sp?) import shop that I have dealt with before. They said they ran the diagnostic checks, adn all that fun stuff. Then they talked about new transmissions. The car can go in reverse just fine, but not forward, and they said it wasn't the B2.

Any ideas?
 

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you need to find another shop. all the symptoms point to a B2 failure.
and that's certainly not fatal to a trans.
try Trans-X first. pull all the vac lines off the bleed valve at the IP.
 

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never done the job from what i hear it can be replaced with the trans still in the car.

go to mbz dot org (delete the spaces) website under articles/trans/b2 and there all is revealed
 
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Symptoms of B2 Piston Failure

Catastrophic failure of transmission in forward gears
Partial engagement of forward gears, with slippage progressively reduced as transmission is shifting from 1-2, 2-3, and 3-4.
Reverse gear engagement normal

Tools needed for checking B2 Piston

Professional-size floor jack (or lift)
4 heavy-duty jack stands (or lift)
10-15 shop rags
Small high power light
Assortment of flat-tipped screwdrivers
Prybar
Metric socket set 1/2 drive and 3/8 drive mostly used 13mm
Torque wrench, low torque settings
22mm open end wrench
Utility knife
# 2 Phillips bit adapter to torque filter screws
5mm Allen wrench adapter
Needle nose pliers
Small articulated inspection mirror
Various pieces of scrap wood. Short 2 X 4 and 1 X 2 pieces



Parts List



B2 piston
O-ring for piston cover
Transmission gasket
~ 4 quarts of ATF (for B2 replacement only)
Heavy grease
Checking/Replacing B2 Piston

1. Jack the car up on four jackstands. I did this so I would have enough room to work safely because I knew that I would be prying the transmission tail end to the side to get enough room for the job. I like to try and shake the car at this point to make sure it is solidly supported.

2. Make sure the hood is open because you will be dropping the back of the tranny and it will force the engine front up a bit.

Remove the exhaust system hanger bracket and rubber donut near the transmission pan area.
Remove the two screws with the thick washers, holding the transmission mount, followed by the other screws holding the two transmission tunnel bottom covers. Note the aluminum spacer for the transmission mount.
Remove the O2 sensor. This was done somewhat for room to work but more to protect it from damage.
Remove the bracket for the sensor connector as well. I'm not sure how they are normally connected to the car frame. Mine is held on by one big sheet metal screw.
Using the pry bar and some scrap lumber, wedge the tail end of the transmission to the driver's side as much as possible. I used an 18" bar. Don't go crazy here and break something.
At this point you should have a pretty good view of what you need to do. The B2 piston is under the more rearward of the round covers on the passenger side of the transmission. It was at this point that I cleaned the working area up as well as I could. These transmissions can't stand hardly any contaminants inside. You should continually think of cleanliness as you perform this task. I used spray brake cleaner and a rag to get as much dirt as possible away from the area. Be sure to wear safety goggles and gloves. Try not to breathe the stuff either. I used a toothbrush on and around the piston cover. I was able to get things fairly clean. Try to clean the frame next to the piston cover as well because you will be getting very close to this as you try to guide the piston in place.
Next thing is to drain the oil in the transmission pan. I needed a 5mm Allen wrench for my drain plug. I didn't drain the oil from the converter because I had just serviced the transmission about 5K miles ago with Mobil I ATF. At $5 a quart I didn't see any reason to lose more than I had to.
Remove the piston cover. It is under light spring pressure and is retained by a heavy wire, retaining ring. To remove this ring, you must get some sharp yet strong object under the end of the ring to lift it enough to then be able to get a small thin screwdriver under as well. Then you pry it out of its groove. I tried many things to get that first initial foothold under the end of the ring but finally ended up using the tip of a Stanley utility knife. This it the type of knife that you can get at home Depot, or the like, that you might use to cut vinyl flooring etc. It doesn't need to be razor sharp either. I fact I would use a somewhat dull blade or drag the edge against something to dull it a bit first for safeties sake. It's pretty tight in there and you don't want to CUT anything, just get something under the end of the ring.
After the ring has been removed you can pull out the cover using needle nose pliers and screwdrivers to rock it a bit and remove it. You will get some oil out the cavity. At this point you must concentrate on keeping things very clean so that no debris gets inside the works.
Next, pull out the piston using a similar method as the cover. You will hear the little pushrod drop with a small clank as it falls out of its position onto the piston bore. You will get more oil too. I cleaned the outer bore up by wiping with a new red shop rag being very cautious to avoid leaving ANY lint behind. At this point you can remove the thin red O-ring from its grove and install the new one. Lube it lightly with some ATF first. It is a bit challenging to get into the groove, but with patience it can be done.
Remove the transmission oil pan. It is held on with 6 screws. I wanted to keep the insides as protected as possible until I had to expose it. This is definitely NOT a job to do outside on a breezy day with dust swirling about. I recommend doing inside your closed garage over a clean floor.
Remove the filter. 3 (#2) Phillips head screws hold it on. Be sure to remove all of the old cork gasket from the valve body if it is stuck on there.
Now you are ready you install the new piston. Installing the piston is a piece of cake. I found that, if I came from back to front with the piston, I could just get it to clear the frame as it went into its bore. The hard part is making sure the pushrod is properly seated as you insert the piston. The close quarters make this a challenging job. There is some recess inside the transmission or valve body that slowly drains, so all during your attempts to get the piston/rod correctly in place, there is this incessant drip of ATF about every 5-10 seconds. Of course for me it ran down my forearm nicely and into my armpit, as I had my hands up by the transmission. It was sorta' like a self-imposed Chinese water torture added to the trial and error of stabbing the pushrod in its position. This should be a simple job except that there was a large white plastic piece, the "B2 band bracket," that blocked my view of the ball socket on the band for the inner pushrod end. I struggled for a few hours to get everything to line up. What finally worked for me was to use the pushrod to push the band end in as far as possible. This allowed me to wedge a small blade screwdriver between a boss on the band and the white plastic piece. This took the pre-load off of the piston. I then used some of the heavy grease (sparingly) to stick the inner end of the pushrod into the ball socket of the band. I was able to get it to stay in a horizontal position via the viscosity of the grease. I was then able to push the piston carefully into the bore and catch the end of the pushrod before it was dislodged and dropped out of the ball socket and onto the floor of the piston bore. When everything finally lined up, the piston slid right on in and the screwdriver that was wedged in between the plastic piece and the band fell out. Also at this point I was able to move the band back and forth using the piston. Along with this there was a brief issue of ATF out of the larger hole from the valve body where it goes into the filter. These were all cues that I had correct assembled the piston and pushrod to the band. Without allowing any slack between the piston and the pushrod, I pushed the piston cover into place and installed the retaining ring.
Double check to make sure the wire retaining ring is securely seated into its groove all the way around

B2 piston 107 270 04 32 $145.20
Lg o-ring 005 997 70 48 $5.46
Inner bush 126 277 08 50 $5.88
Seal for bush 006 997 73 47 $5.18
K1 spring kit 126 270 44 77 $15.60

Grand total with tax..........$187.96


FOR REFERNCE ONLY The B2 piston in specific transmission numbers within the 722.xxx category
 

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Folks,

I have the same year MB with 185000 and my transmission has the exact same symptoms; no forward drive but reverse is OK. I have removed the B2 piston and all looks fine. The trans is out of the vehicle and have begun its disassembly. Nothing out of the ordinary has surfaced. All looks normal, no excessive wear on bands, etc.

Could I have a valve body issue?

Where do I find a diagram of the valve body?

Thanks for your help!!
 
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wjmanson - 3/23/2005 3:43 PM

Folks,

I have the same year MB with 185000 and my transmission has the exact same symptoms; no forward drive but reverse is OK. I have removed the B2 piston and all looks fine. The trans is out of the vehicle and have begun its disassembly. Nothing out of the ordinary has surfaced. All looks normal, no excessive wear on bands, etc.

Could I have a valve body issue?

Where do I find a diagram of the valve body?

Thanks for your help!!
I don't know if this will help?

http://www.jie.com/Mercedes/w4a020Sch1.htm

Louis.
 

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Discussion Starter #11
Update:

They checked the B2, and it was intact. They mentioned something about the pump in the trans that maybe the culprit, it might be the same problem. It is however, still too expensive to fix and I have no choice but find a new car, but...

On a scale of 1 to 10, how hard is it to dismantle and rebuild a transmission?
 

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You may want to try a salvage yard for a "carefully selected used trans". I am a believer in junk yard parts. Just look for a low milage smashed MB and I think you may be able to obtain a reasonably priced used transmission.Good Luck!
 

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Thanks Louis, this was very helpful and I appreciate the help. Do you know what the difference would be in our 722.416 transmissions (W4A-020) and the same (W4A-020) transmission out of a 96 C220? I found a Mitchells diagram on a search and the box looks identical, I assume the valve body may be different due to electrical but the tear-down diagrams are wonderful and very clear. Thanks again.

Bill
 
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