Joe:

If the gearshift feels different, check that out. Many times, the short piece of aluminum that guides the shift cable at the very end at the transmission end will break off, allowing the cable to bulge out and not move the lever.

The other common thing is for one of the axles to fall off the transmission stub axle....but that won't make the lever feel different.

 

First I'd like to thank every one here for the great advice and quick replies!!

I've got to run between our refinery in Lupton, Az. and Vegas, this week. I'll check every thing out ASAP. When this happened it was already dark out side, so getting the car back in the garage, and off the street was my first concern. It's in the garage, and will be on my lift ASAP.

I'll post my findings, hopefully it's some thing simple, but I think a complete rebuild is in the future.

 

These automatics are all getting to the very end of their life span.....they are all going to need to be rebuilt. Hopefully, pieces will still be available.

Porsche has made many of the 'routine replacement" parts NLA....and Mercedes has "updated" their prices 500-600% higher on some items.

My experience with Porsche is that as they get low on pieces, the price goes up. I'm hoping that is not the case with Mercedes and the new prices simply reflect what is costs to make these pieces today, not the fact that they are running out of the pieces and have no intention of remaking them.

 

Greg,

Can I buy a parts kit from you while they are still available? Then either leave it there with my name on it, or have it here and ship it on the pallet with the gbox when it craps out. Or just send the box down now while it's still "working fine" and get it refreshed. Car will be hibernating for the winter and wouldn't miss the transmission too much. Better now when it's convenient or wait until the funny noises start and the car won't get me home. 110k of white-haired guy driving, should be good as new inside, right?

 

I had something similar happen on my 84 many years ago.
But with mine, reverse continued to work fine, but no forward gears.
It turned out it was a broken B2 piston up inside the assembly.
I was able to replace the part without dropping the transmission.
Everyone said that was impossible, but there's a small access cover.
I posted a write-up on the procedure but that was back on the email list.
It required modifying a couple of my tools into odd shapes, but it worked.
That transmission continued to work fine for many years until I sold the car.
It gave no warning; It just snapped during my morning commute to work.
The funniest part was I drove all the way back home in reverse!
I would sit and wait on the shoulder until the traffic cleared.
Then I would haul *** in reverse until I saw cars and pull over again.
I gradually worked my way back home about three miles that way...
So does your reverse still work..?

 

No, nothing. Shifter does move with very little to no resistance. Might be a broken cable, but I never have that kind of luck.

 

I had exactly the same symptom, and it was in fact a broken shift cable. When you get home, parking brake set, you can reach up underneath the left side of the gearbox, or use a mirror, as your trusted assistant moves the gear lever.

Even easier, the factory installed a set of diagnostic lights in the instrument cluster exclusively for verifying that the position of the selector lever in the car is telegraphed perfectly to the selector lever on the side of the transmission. Very thoughtful of those early engineers I think. Perhaps they anticipated the cable failure 40+ years ago when they designed in that diagnostic system?

 

Thanks, Dr. Bob! never thought of that!
Just checked, and every gear lights up on the dash. Trans is toast.

 

Or the switch itself.

 

My money's on door #1 given the description of the selector semi-freewheeling.

 

Got it up, and the selector moves thru the gears as it should. The car will roll forwards and backwards, in park. Start it and the torque convertor spins as it should. With the engine off, the wheels rotate in opposite directions, when turned by hand.

What else to check?

 

fluid level still OK? I think that was an early question.

Kevin-- The switch is working OK, If it wasn't, the dash shift lights wouldn't work. And it would be tough to start the car unless it 'failed' in Park or Neutral position at the switch. I'd look at the switch if the lights -didn't- change when the trans selector lever was actually moving.

----

The shift cable attaches over a ball on the selector lever on the gearbox. There's a hairpin retainer at that joint that you'll need to remove (and not lose...) before you pop the cable end off the ball. Once that's removed, the selector lever should move with very pronounced detents at each gear position. IIRC, The mechanism for that lever is accessible inside after dropping the valve body, with the detent stuff is close to the outside edge of the trans. If your lever is amazingly free of those detent stops, look inside.

 

The clutches and bands, which are (should be) essentially disposable parts are still available. And although the factory prices have increased, its not a dramatic increase. I can get clutches made by Borg Warner, also, although I prefer the factory Mercedes pieces. There are also what appear to be high quality "offshore" bands....and I use these in my "economy" rebuilds. I just don't know how long they will last. The Chinese are pretty good at making pieces that look great, but turn out to only look that way.

The steel plates that the clutches ride on get hot spots from slipping once the seals on the pistons start leaking. While I could supply them, they come in a bunch of different thicknesses and it is very difficult to guess what any particular transmission is going to have. These parts have gone crazy. I was buying them for about $10.00 when I started. Some are over $80.00 now! Most of the "one price" rebuilders simply "attack" the hot spots with an aggressive sanding disc on a die grinder, however that simply reduces the available surface area for the clutches to grab onto and accelerates wear on the new clutches. I replace them, in order to actually "rebuild" the transmissions back to as close to new as I can make them.

The drums that the bands grab onto have gotten expensive, but if the transmissions get rebuilt before they no longer go forward, the drums can usually be re-used. Again, it's a "hot spot" issue, from slipping.

 

Joe:

The car should not be able to roll in park. That's a 100% mechanical function, not a "mystery" automatic transmission function. (It's internal, but it's mechanical.)

The shift cable moves the lever at the transmission when someone is moving the selector inside the car?

 

Greg,
Dee was in the car moving the selector. It moved from one selection to the next and back. I was under the car while she moved the gear selector. The car does roll in park.