Here is the bore:

 

This is of the damage to the band. Looks like the pin came loose some how and bent/creased a lip into the band. Don't know if I can hammer/flatten it back down. Or it needs to be replaced? Or even what could hae cause the pin to come loose like that?:

 

Well, what should I do?? Can it be fixed?? Without tearing it apart? Or does it need to be pulled, the b2 replaced, and rebuilt? Or should I find another tranny?? Let me know guys...

Jim

 

Since it’s the updated B2, the snout is supported by a plastic bushing, which should have been installed into the case bore. The piston was not applying on a horizontal plane; probable cause, bushing is missing, worn or the aluminum one was never replaced. Or missing plastic band guild. Did you remove the seal and bushing in the case.


The only true, confident fix is to replace the band; you may be able to save the B2 piston by sanding the snout with 220 wet paper. The B2 reaction valve is also damaged.
Install a new plastic bushing and seal, check the band piston travel and adjust if necessary by installing a longer apply pin. And try it, The B2 piston is applied in 1st, 2nd and 3rd gear, it will not last.

 

Steve, yeah the piston was of the newer design, but it had the metal bushing, which I suspect did the scoring. To remove it, I dropped the pan and the valve body. That's when I saw the smaller pin laying on top of the plastic guide. Didn't appear to be anthing wrong with the guide. I went ahead and bought a new piston! (Thought sure that was the culpret and no one said anything different) Also bought the newer plastic bushing and seal. And a new longer pin.

So I should relace the reaction valve also? What is the part number? Also found a piece of a small cap the would appear was on the pin. Guess I will try to see if I can get that part and put it back together.

Jim

 

Jim,

Here's my theory on what happened. There was some binding between the piston and the metal bushing which kept the piston in the "pushed in" position. When the piston finally released (pushed out), it did so with such force that it caused the band to rotate slightly. This allowed the opposite pin to slide out of position. When the piston re-engaged (pushed in), the pin was forced into the band causing the damage.

From the pictures, I can't tell if the damage to the band is cosmetic or if it's something that will seriously affect the car. Will the shorter pin stay in place, or is the bore (of the band) completely destroyed? If the bore (of the band) isn't completely damaged and the pin does not fall out, I would replace the parts (piston, plastic bushing, longer pin & reaction valve) and see if you could get the car to move. It may be enough of a "fix" for you to drive the car to a shop for inspection or repair.

Regards,
Roger

 

There are three different design reaction valves, use the transmission identification number stamp into the passenger side pan rail and order the correct one from MB. to replace the valve remove the neutral safety switch, make a reference mark from the switch to case, it is adjustable, no start adjust switch then remove the valve by pushing it in, change the sealing ring in the case, if you don’t it will leak. Before you do anything make sure the band is not cracked/ broken.