B2 piston repair questions

[JDmills]

Wednesday I made an attempt at replacing the B2 piston in my 84 300TD. The end result is that the car acts the same as it did before the replacement. That being said, the old B2 was in pieces when I took it out...

I guess my question is How does the B2 piston work, Does it push against the b2 band to provide friction...? and when I took it apart there was spring pressure against the b2 cover, is there supposed to be a spring that pushes against that cover to keep the piston toward the inside of the transmission? Or does transmission fluid provide the force? One other question which I wondered about is this: some of the pictures I saw on installing the b2 use a special tool to push the piston/cover into place suggesting that it is a bit of a bugger to drive into place... mine slid right in with very little effort, could it be the wrong part?

[whunter]

Some of these links may help answer your questions.

Transmission:
Transmission:





Have a great day.

[Ralph69220d]

wHunter,
You are probably the best forum member on this site for good links to answering questions (not discounting other member's who also provide good links when appropriate). You are one of the forums indispensable members. Not a bit of idle "pat on the back" in that.

[C32AMG]

The B1 piston has the heavy springs, did you remove the B2 showed below , if so did you install the band apply pin showed in the picture. The pin applies the band; maybe it did not engage the band. Remove the B2 and insert the pin into the B2 with cold Vaseline to hold it in place, and reinstall it, did you change the B2 bushing and seal. Did you notice if the B2 band was broken /damage when you removed the valve body


.

[JDmills]

oops...

The band apply pin is still in my collection of "used parts" and not in it's proper place. That is why it doesent work! I made the assumption that it was a part of the broken B2 piston that I took out, and did not realize that it has another job to do. will try the cold vasaline 'glue' trick..
Thanks for your help. Do you rebuild these transmissions for work, or have you just been playing with them for a while? How about rebuilding the manual transmissions in the 240D's? Is that a tricky job, or fairly standard? I was having visions of swapping a 4speed in to the 300TD.. there is a donor car about 20 miles away that may be able to be had. Also I tell myself that it may boost my mileage, as well as being more predictable about when it is about to go south.
That being said, as I recall, the automatic in the car has been shifting slightly harsher than it used to. (and the vacume supply has been disconected since before I owned it) as if it is working 'better' than it was 20K ago.. was going to take a crack at adjusting it to shift correctly when summer/dry weather arrived.

[C32AMG]

No one is perfect; the apply pin will make a big difference in the way that car drives. MB manual can be expensive to rebuilt, hard parts are costly. Manual can be tricky and frustrating if you don’t know the disassemble, reassemble sequence, you will need specialty tools, bearing pullers , installers, snap ring pliers, and most important, the experience to identify a bad or useable part. Do a search on the diesel forum for the vacuum problem

Originally Posted by JDmills

oops...
Thanks for your help. Do you rebuild these transmissions for work, or have you just been playing with them for a while?

You are Welcome
I just played with them for a while, when I was 17 years old, every make and model , automatics , manuals, transfer cases and differentials, five days a week for the past 36 years.

[JDmills]

I just played with them for a while, when I was 17 years old, every make and model , automatics , manuals, transfer cases and differentials, five days a week for the past 36 years.

Wow. That is, from my perspective.... Stout! I will never have that level of understanding, or even a years worth, but I admire your depth of knowledge.

Still struggling with the TD, pulled the B2 piston, used some vaseline and thought I had it all buttoned up.... not much of a difference in how the car engages first gear. Off to Colorado for two weeks. Will give it another crack when I return. Thanks again for sharing your experiences and making the process manageabe for the likes of me.

Jason

[JDmills]

C32AMG
This transmission may get the best of me yet... I got the car together and it runs and shifts fine. yesterday I noticed that it was leaking a bit of transmisson fluid. From the B2 piston cover of course.. I Dont remember exactly how the cover was sealed in the bore, but could I have nicked or twisted the seal, so that it now leaks when under pressure? Have you got any quick ideas? I am thinking that I may call the dealer and see what kind of seal is used..
Jason

[C32AMG]

The seal for the B2 cover is a red rubber o-ring that seats in the bore, remove the cover only and you will see it, an easy job.

[JDmills]

Last question: can I do that with the transmission in the car, or will I be miles ahead if it comes out first?
J

[whunter]

Originally Posted by JDmills

Last question: can I do that with the transmission in the car, or will I be miles ahead if it comes out first?
J

In the car...
This is not a hard DIY.





Have a great day.

[Matt L]

Originally Posted by C32AMG

MB manual can be expensive to rebuilt, hard parts are costly. Manual can be tricky and frustrating if you don’t know the disassemble, reassemble sequence, you will need specialty tools, bearing pullers , installers, snap ring pliers, and most important, the experience to identify a bad or useable part.

Remove MB from that statement. I've never come across one for which hard parts weren't very expensive, and while differing between manufacturers, they all have a fairly precise disassembly/assembly sequence and require some special tools.

[JDmills]

Thanks Hunter,

I just needed a little encouragement. It was almost more difficult to get the old one out, then the new one popped right in.
Jason

[C32AMG]

You can remove the cover with the transmission in the car as Said , push the cover in and remove the ring. 1/2 an hour job, you can do it.

Matt L Quote:
Originally Posted by C32AMG
MB manual can be expensive to rebuilt, hard parts are costly. Manual can be tricky and frustrating if you don’t know the disassemble, reassemble sequence, you will need specialty tools, bearing pullers , installers, snap ring pliers, and most important, the experience to identify a bad or useable part.


Remove MB from that statement. I've never come across one for which hard parts weren't very expensive, and while differing between manufacturers, they all have a fairly precise disassembly/assembly sequence and require some special tools.
Today 02:14 PM

OEM MB manual transmission parts are expensive; the same is true for any parts you have to buy from a dealer (OEM,) when there are no after market sources available.


last week I a rebuilt a ZF S6- 650 transmission, it needed an input shaft, cluster gear, all main bearings, synchronizer rings, seal and gasket set. My cost for parts was $ 754.32.

Those same parts for a MB 5speed would be over $,1500 or close too it.