byrdman454

Lost all forward gears on the way to work last week in my S4. The transmission is out of a '91. When I rebuilt it, it had the most up to date B2 piston. This was my first guess on what happened to the transmission. Took the B2 piston out and disassembled it, but it was intact. Removed the valve body and rear plate and a piece of the B2 band fell out. Not good. Lots of work to replace.

A new B2 band is over $300 from Porsche. Is this a part that should be replaced new or will a used part be fine for a replacement? i have an extra transmission from my '88 that already needs rebuilt that I could steal the part from. Does anyone else have a band already removed they might want to sell?

Let me know your opinions on replacing used or new. I have not heard about this failure very often. Has anyone else?

Thanks

brutus

OH mg $300 for a trans part !!! outrageous ... why would you even consider a used part. The brake band is like a timing belt or brake pads they are designed to wear out.

Speedtoys

$300 aint that bad really.

Bout the cost of a decent set of brake pads and fluid...

namasgt

If its a Mercedes part you may be able to get it from Mercedes a lot cheaper. See if there is a Mercedes part number.

Bill Ball

It's an MBZ part in PET: 1262702062. About the same price whether from Porsche or an MBZ supplier.

GregBBRD

The B2 bands do break. I've seen a couple of them break on stock transmissions. I put a new one into almost every transmission I rebuild....seems like a "wear item" to me, that should be replaced. I'm not into "how cheap can I rebuild this transmission to maximize my profit". I'm into trying to make each transmission I rebuild last as long as the orignal one did.

It's a very different thing, that I do.

That being the case, I'm sure I have some very nice used ones.....as I tend to keep pieces that look nice, in case they get hard to find or very expensive. I also keep brand new ones, in stock.

BTW....the "updated B-2 piston" also requires an updated "shock absorber piece" on the other side of the brake band. Not many people pay any attention to this "minor" fact and tend to ignore it. I install the new "updated shock absorber piece" every time, also.

I figure the people at Mercedes that superceed these parts are way smarter than I am...

I'm not at work, but I'd be glad to look through the "box-o-used transmission pieces", tomorrow. I'll also check how much I pay for a new band....although they are, indeed, not cheap.

byrdman454

Considering I bought the whole transmission for $500 and already rebuilt it, the part is expensive in comparison. The only reason I asked about using a used part versus new is if this failure is a very rare event and would only be due to a defective part, then I would consider a used part. Thanks for everyone's opinions on the new versus used idea. Sounds like new is the overall opinion.

I am still thinking about my options. All the labor of pulling the transmission and disassembly is what I am really dreading.

Was not aware of the shock absorber piece on the B2. This transmission has the updated piston (was already in the transmission when I got it), so I would hope it has the updated shock absorber. If not, this may be the cause of my band failure. I will have to double-check this when I tear it down.

dcrasta

Curious did you have any warning symptoms such as slipping, late shifts? What lead up to the total failure?
Or did it just happen 'out of nowhere? '

Dan87951

Sorry to hear about your failure. I was just going to tell you to try Merc dealer for your part but looks like they are the same price. Is your car boosted?

SMTCapeCod

Not vouching, just searched:

http://cobratransmission.com/index.p...ucts_id=901007

http://www.importecwarehouse.com/Mer...1262702062.htm

GregBBRD

I only mention the updated "shock absorber" because it logically seems to me that if the B2 piston "hits" the brake band harder...it might be possible for this harder "hit" to break the band. I actually have no idea why they change this stuff....again, they are way, way smarter about their own transmissions than I could ever be.

All of the B2 band pieces have been superceeded several times since your transmisson was built. I try to keep the whole thing pretty simple and install a new band, with an updated piston, with an updated "shock absorber" everytime I rebuild one of these. Seems like that gives my customers the best chance of getting something that lasts.

I looked in my box-o-used transmssion pieces and found the B2 band I was thinking of. It is a band with the updated newer material (meaning it got replaced at some point in time) and appears to be perfect. Since I think a "rebuild" should be a "rebuild" and not a "replacement only of the pieces that won't last 24,000 miles" (like most automatic transmission rebuilders), I set this to the side. Yours for $150.00, if you want a perfect looking, updated, used part.

byrdman454

Greg, thanks for the offer. I will let you know. I am still mulling over what to do. Just getting started ripping back into this car is killing me.

Besides the B2 band, B2 piston, B2 shock absorber, and kickdown spring (from the other thread), what other parts to do change every time you do a rebuild? I would like to know. I may decide to pay the money now and give myself the best chance of never doing this again.

Thanks

fbarnhill

Greg, I too, would love to hear the list of parts you reccommend replacing every time. I have an extra trans sitting on the bench waiting for me. I intend to take my time and learn all I can while rebuilding this thing. Fortunately for me, the suggestions from you guys have my current transmission shifting just like a sports car should so I have no complaints. It just seems to me that it can't hurt to have a good one waiting to go in if the current one bites the dust.

ROG100

In this case the Porsche price is cheaper than Mercedes for a change. But Greg's offer is the way to go if you need the part. Don't you love this community?

GregBBRD

This gets fairly involved...because I don't mess around with stuff that is "partially' worn or has "a few" hot spots.

If it doesn't look new, I replace it. Again, I'm not building transmissions for the guy that wants something which will last 12,000-24,000 miles...or until the warranty is over. (Most "flat charge" transmission rebuilders are experts at knowing what will last long enough to accomplish this.) I'm building stuff that I expect to last as long as the original one did.

Here's the minimum of what I replace:

Gasket/Seals. I buy/use the genuine thing from Mercedes.
Main thrust bearing.
B2 clutches and steels, if the steels have hot spots (Almost always). Genuine only.
Assortment of shim circlips/steels to "adjust" the B2 clutches.
B2 band. Genuine only.
Updated B2 "shock absorber".
Plastic piece to retain plunger on "shock absorber".
Updated B2 piston.
B1 clutches and steels. if the steel have hot spots (Almost always). Genuine only.
Assortment of shim circlips/steels to adjust the B1 clutches.
B1 band...Low wear item...many times this appears to be virtually unworn and will still have the orignal "printing" on the friction material. I do not change these, when they appear to be virtually new.
Plastic piece to retain plunger on "shock absorber".
Reverse clutches. Steels seldom have hot spots...but the clutches are the highest wear item in the transmision. Genuine only.
Reverse operating spring retainer and circlip...sometimes the springs.
"Shim/outer ring" that the reverse piston "slams" into. Always bent into a arc.
Custom restrictor for reverse. The "new" clutches are extremely aggressive and "hit" very hard, without this.
Modulator.
Rebuild valve body...50% of the valve bodies have broken springs inside the valve body. I replace the check valves, etc, inside the valve body.
All seals/gaskets for the differential section...these do not come in the Mercedes gasket set.
Kickdown return spring.

I might have missed a couple of things....not sure.

Other than this list, it depends on what is worn/broken.