S.O.S ~ Transmission won't shift into anything!!! - PeachParts Mercedes-Benz Forum

Knuckleballerr · #1 02-11-2013, 01:14 PM

1984 300sd turbodiesel

After having gotten out of class, I shifted the car into reverse and backed out of the parking space (intentionally by gravity, not by engine power). I went to put it into drive but it didn't shift no matter what. ~ I had to back it into a handicapped space (no other open spots). The only unique observation is that the shifting seems to be making a "clink" sound? Not sure if its normal or not (don't really check to hear for it, you know) What would be wrong that the car won't shift into drive, reverse, anything?

junqueyardjim · #2 02-11-2013, 01:22 PM

It's probably a transmission problem. Oh, you knew that! But anyway, it could be any number of things. Was the trans low on fluid? Did the car show any symptoms before complete failure? Instantaneous failure with adequate fluid and no warning is probably a failure in the front pump, unless the selector got loose and fell off the transmission. But I'll put my money on the front pump. Probably better start looking for a used one.

Stretch · #3 02-11-2013, 01:27 PM

Welcome to the forum Knuckleballerr

Did your car always start no matter which gear it was in? This is unlikely as it should be stopped by a safety switch but people do hot wire them sometimes - if this is the case then I'd suspect that the gear selector mechanism is possibly at fault...

...does "park" engage properly? Put it in park and try to push the car - what happens?

Otherwise I'd suspect that the front pump has died.

You could have a massive fluid loss of course - but I guess you'd have noticed that one - right? (You would have noticed that right?)

Knuckleballerr · #4 02-11-2013, 02:30 PM

Quote:

Originally Posted by Stretch

Welcome to the forum Knuckleballerr

Did your car always start no matter which gear it was in? This is unlikely as it should be stopped by a safety switch but people do hot wire them sometimes - if this is the case then I'd suspect that the gear selector mechanism is possibly at fault...

...does "park" engage properly? Put it in park and try to push the car - what happens?

Otherwise I'd suspect that the front pump has died.

You could have a massive fluid loss of course - but I guess you'd have noticed that one - right? (You would have noticed that right?)

No massive fluid loss and haven't had any starting issues. ~ It goes into park just fine. I just noticed something odd though. When I put it into N to push it onto the tow truck, the reverse lights went on.

Stretch · #5 02-11-2013, 02:48 PM

Quote:

Originally Posted by Knuckleballerr

No massive fluid loss and haven't had any starting issues. ~ It goes into park just fine. I just noticed something odd though. When I put it into N to push it onto the tow truck, the reverse lights went on.

The engine should not start unless the gear selector lever is put in park or neutral. If it starts in any other setting then there's something wrong / something modified.

If you can push the car (along the road) when it is in park then there's also something wrong.

You might find that the selector linkage is out of whack if you are getting reverse lights shining when neutral is selected. This is a cheap and simple check to make - front pump failure is more expensive to repair.

rs899 · #6 02-11-2013, 03:26 PM

Could be your shifer linkage is like totally totally disconnected. It happened after you started the car. $hit happens. Hope for the best.

greazzer · #7 02-11-2013, 03:34 PM

Check your transmission coupler. It's the 3 dog eared splined part that connects to the flex disk. There is a funky 12 pt 30mm nut that holds it on. Mine spun right off and I was buzzing along the interstate doing 70-ish and then NADA ... Very simple repair and fix. I was ready to pull my transmission until I got a phone call from Phil around midnight my time telling me to check for this. BINGO ! Instead of a new trans ... it was that funky 12pt 30mm nut and VERY SIMPLE and VERY FAST to fix.

Biodiesel300TD · #8 02-11-2013, 05:10 PM

I'd check the shift linkage. There are grommets on either end that rot away and fall out.

kerry · #9 02-11-2013, 06:11 PM

Search on B2 piston. If it has reverse, it sounds like a B2 piston failure to me. Not that big of a problem.

jay_bob · #10 02-11-2013, 06:24 PM

Quote:

Originally Posted by Knuckleballerr

1984 300sd turbodiesel

What would be wrong that the car won't shift into drive, reverse, anything?

I thought B2 as well but I saw this in the OP.

I think either his linkage is loose or he lost his coupler nut like greazzer said.

ROLLGUY · #11 02-11-2013, 06:59 PM

I have the same problem with one of my cars. It was driving just fine, when it would not move in any gear after parking it. I replaced the ATF, and still no change. I know the pump is working, as it took about 5 quarts of fluid (drained about the same amount from sump and TC) and read correctly on the dipstick. If you find out that it is something simple, I will check the same thing on mine.

rs899 · #12 02-11-2013, 08:07 PM

ROLLGUY-

Does yours do this?

Quote:

The only unique observation is that the shifting seems to be making a "clink" sound?

ROLLGUY · #13 02-11-2013, 08:10 PM

Quote:

Originally Posted by rs899

ROLLGUY-

Does yours do this?

Does nothing. No noise, no movement in any selection of the shifter.

kerry · #14 02-11-2013, 08:12 PM

Quote:

Originally Posted by Knuckleballerr

I had to back it into a handicapped space (no other open spots). ?

That's what made me think reverse was operational.

jay_bob · #15 02-11-2013, 08:45 PM

To the OP:

It is critical to clarify whether the car can move in reverse under its own engine power. If this is true then that changes the diagnosis significantly.

If the car can move in reverse under its own power then the problem is most likely the B2 band brake piston as mentioned above.

The B2 piston applies the B2 friction band to the drum inside the transmission, that is responsible for engaging the three lowest forward gears. If this piston fails, it is impossible to move the car forward. A different band brake engages reverse, so if the car can move in reverse, it strongly suggests a B2 failure.

Luckily this is neither expensive nor difficult to repair, the hardest part is securely raising the car so you can get underneath to change it out. The part is on the outside of the transmission and does not require removing the transmission to replace it.

BTW, I would do whatever is necessary to pull the car out of a handicap spot (assuming you don't have a placard). I don't know your local laws but they show no mercy in SC for that sort of thing.