G Man

Hey Steve C. I sent you a PM last week with some questions about the trans in my 84'. Did you get it? If not let me know and can send it again. If my questions are out of line, let me know and I will look else where for info. Thanks.

Jim G

Tails

Steve,
I have sent a copy of the report to you e-mail address (the one you nominated above), as I believe the report maybe too large to be posted here.

Can you please forward a copy to Tim and post it on the 928 Forum as I'm running out of time before I go on holidays.
Thanks.
Tails 1990 928S4 Auto

Steve Cattaneo

HI G man,

I thought I responded to you Question, if not I apologize,.Post your question here and I will try to help you if i can.

G Man

Steve. Here is a copy of the PM I sent you.

--------------------------------------------------------------------------------

Hi Steve. I have a 84 982S that I would like some advice about the trans. You have replied to my posts in the past about my trans not holding the gears long enough between shifts. I have taken all of the slack out of the cable and still have the same results. I took my local trans guy for a ride this a.m. to see what he thought. He said it is definantly shifting through the gears faster than it should. We did numerous starts from a dead stop at different throttle positions such as very light throttle to full on floored as far as it would go. He said we probably need to install stiffer springs in the valve body to get it to hold the gears longer. Do you offer any type of a packaged "kit" for the 928 trans. I would like to have the work done here if I can. I know you offer rebuilt valve bodies that offer first gear starts and livlier performance. I was wondering if there was a kit available that I could get to my local trans guy to install. If it is a basic mod that any good trans guy can do would you be willilng to share the procedure. Any info would be helpful. I tried to call the shop today at about 3:15 your time to chat with you, but got no answer. I'm sure you guys are busy. Any info will be appreciated. Thanks

Jim G

TimCo

Steve,
I've got all four parts. My local Mercedes dealer got them in 2 days. The parts counterguy was very familiar with it. He said they called it a 7223 (722.3). He said Mercedes put it in all the big cars with V8's and big 6's. The smaller cars (small 6's and 4's) used ... I think he said the 722.5.

I saw where the 7347 seal is located when I took the piston out. But, I didn't see where the 0850 plastic bushing is located.

I'll post photos of these new parts and the side of the trans. I found some articles on the 7223 which I can attach also.

Installation looks pretty straightforward ... but there is probably a wrong way to do it. So, I'll wait for some instructions.

Thanks Steve, I really appreciate it.

Tim

TimCo

Steve, it looks like the 126 277 08 50 plastic bushing just slides onto the shaft of the B2 piston. But, it can slide on with the lip towards the outside (cover) or towards the inside (seal). I can't find any reference on the web to which way it goes.
Tim

Steve Cattaneo

Tim CO, We are going to remove the old seal and bushing without removing the valve body.

The old seal and bushing comes out thru the piston bore, use a flat head screw driver and hammer, gently crush the out side ends of the old seal into its center. Do this to the point were you can remove the seal.

Once the seal is out the aluminum bushing can be removed try with your fingers first; you might need some type of hook devise behind it, if you have an old screw driver heat the end and bend it into a hook. Clean the hole and piston bore well with the RED scotch brite.

Install the updated plastic bushing and the new seal with the lip / ridge facing you, in that order. You are going the need some sort or driver for the seal, you can use a big flat washer. Drive the seal in straight. Do not install the piston; we need to modify the T seal. I am going out; I will be back around five.

TimCo

Steve,
After writing my last post, I found the p/n on the schematic. It's on the transmission layout diagram which shows the transmission (left is front). I was paging through the pdf, looking for the view of the pass side but never found it. But, it was on the drivers side view ... there was an exploded view of the pass side.

Here's a couple photos of the new stuff and the hole in the transmission. You can see the seal but you can't see the bushing.

Thanks Steve.

Steve Cattaneo

The aluminum bushing is held in by the seal, remove the seal and you will see the bushing

Steve Cattaneo

G man



Yes you can change the pattern of a shift sequence by changing the spring, but that is not your problem. Very unlike all 4 springs lost there tension on the command /shifting valves.




What else have you done to solve this problem? Did you adjust the full throttle control pressure in the valve body? It’s the Allen screw on the front valve body, the hold down plate has three screws. ccw rises the all up shift points


There is a possibly you do not have any kick down. With the passenger side door open key on, floor the gas pedal you should hear a click at the rear of the transmission?

Other possibilities, the wrong governor pressure, bad governor, a stuck full throttle control valve or broken spring, a stuck throttle valve,


I would start by checking working/ line pressure; all others pressure originate from it. Give me the 722 numbers that are on the passenger side of the transmission above the pan and i will tell you what the pressures should be.

TimCo

The seal was a bear. It was rubbery like the new one. It was hard and brittle. It took some gyrations with the hammer but I eventually sharpened a long screwdriver on my belt sander ... to a razor sharp edge. I lined it up and hit it with authority twice and split it. I pulled it out with needle nose pliers (like you would the clip on the cover). If I had to do it again ... I wouldn't spend so much time looking at it ... as I did. The chisle hit the bushing and left a mark ... but since its being replaced anyway ... I think the chisle is the way to go. But, the trick about using a chisle is to sharpen it razor sharp.

But, yup ! The bushing was right underneath. I stuck my finger in there to see if I could feel; and I couldn't so I pulled my finger out and the bushing came out on my finger. It was just laying in there; wasn't pressed in at all.

OK Steve! So far so good. What's next?

Tim

TimCo

Correction, the seal was not rubbery like the new one.

Steve Cattaneo

Prep the bore; deglaze it well with the RED scotch brite. The T seal is very hard in that condition, it will not expand and seal against the bore; remove it from the piston carefully. You have to get behind it and pray it off then cut it with a razor blade. When you put it back on, install the piston with the opening/cut of the TSEAL at the 12:00 position. Don’t forget the new band pin. Use Vaseline as glue to hold it in the piston. Change the red outer seal; install the cover and you’re done.

TSEAL

TimCo

Steve,

Wow! The light at the end of the tunnel.

So, you cut the T-seal so it's like a piston ring? Really ... Well, OK! I can dodat. I'll get this done in the next day or so and let you know.

Thanks very much,

Tim

Garth S

Steve/Tim,
Could you please explain the selection criteria for a new band pin? ie. - should it be made x tenths of a mm longer to compensate for B2 band wear? ... or 'shortened' due to the updated piston? ... or just reinstall the orriginal pin?
Thx