transmission woes - PeachParts Mercedes-Benz Forum

Rooster300SD · #1 05-05-2018, 10:15 PM

Hi all,
Automatic transmission suddenly stopped working.
No reverse no drive... nothing. Had to get towed home.
The linkage from shifter to trans is connected fine.
Fluid level good.

I read about people having the same symptoms with the staked nut to the tranny output flange going bad.
I dropped the driveshaft and the staked nut and output flange look good and are tight. No looseness at all.

What's my next move?

Thanks,
Jeff

andrewjtx · #2 05-05-2018, 10:32 PM

I'm getting a rebuild.

Probably is most likely main pump failure. If you have to drop it, might as well do it only once.

Marc at Sun Valley has one on the bench for me right now...

ROLLGUY · #3 05-05-2018, 10:55 PM

I bought a car with the exact same issue. No movement in any gear. I used the car for parts, and never figured out the problem with the trans. I did check for fluid flow to/from the cooler, and flow was present. I was told that if there is fluid flow, the pump is good. As far as MB trans rebuilders, there is none better than Sun Valley Mercedes Transmissions. Marc is a great guy, and he knows his stuff when it comes to MB transmissions. You won't be disappointed with any work he does......Rich

Rooster300SD · #4 05-05-2018, 11:36 PM

Thanks for the replies. A few years back I pulled a manual tranny
from a Euro 300d. I've even got the bigger (38 lb?) flywheel for the 617 engine.
It's just sitting here. Hmmm....maybe it's time for the W126 manual tranny conversion.

What do you think???

Jeff

ROLLGUY · #5 05-05-2018, 11:40 PM

Quote:

Originally Posted by Rooster300SD

Thanks for the replies. A few years back I pulled a manual tranny
from a Euro 300d. I've even got the bigger (38 lb?) flywheel for the 617 engine.
It's just sitting here. Hmmm....maybe it's time for the W126 manual tranny conversion.

What do you think???

Jeff

I think it is a great idea. I too have a car ('82 300CD) that has no fourth gear. I have a complete 4 spd setup from a 240 that I am thinking about swapping in. There was a user years ago that came to my place with an SD with a manual, and he absolutely loved it. I think the only challenge for him was the clutch pedal. I am not exactly sure what the issue was, but he did solve it.

sixto · #6 05-06-2018, 02:04 AM

Set the transmission in park with the park brake disengaged. Can you roll the car?

Sixto
98 E320s sedan and wagon

Rooster300SD · #7 05-06-2018, 10:09 AM

No, it is locked when in Park with no parking brake.
The trans output shaft spins freely in both directions in all other gears.

Jeff

sixto · #8 05-06-2018, 10:49 AM

I got my second ‘83 SD rom a forum member when the output shaft splines sheared. The yoke spun freely on the output shaft. That’s not your problem if it holds in park.

My ‘81 SD came with a torn flex plate. Someone mentioned pulling a transmission cooler line to/from the radiator to check for ATF flow with the engine running. It’ll fill a gallon jug in a few seconds so have someone start the engine then kill it on your command when you confirm healthy flow. Pour what comes out back into the transmission. If there isn’t more than a dribble, you might have lost the front pump or torque converter.

How long did it take to engage drive or reverse leading up to this failure?

The transmission has ports to which you can connect a pressure gauge. An ALDA banjo bolt works. That gets into the you know what you’re doing realm where I’m not qualified

Sixto
98 E320s sedan and wagon

Rooster300SD · #9 05-06-2018, 11:21 AM

How long did it take to engage drive or reverse leading up to this failure?

Now that you mention it, seems like there has been a bit of a lag lately before the gear would engage.
I will do the flow test with a transmission cooler line and report back.

Which transmission line should I disconnect for the test?

Thanks Jeff

ROLLGUY · #10 05-06-2018, 11:25 AM

Quote:

Originally Posted by Rooster300SD

How long did it take to engage drive or reverse leading up to this failure?

Now that you mention it, seems like there has been a bit of a lag lately before the gear would engage.
I will do the flow test with a transmission cooler line and report back.

Which transmission line should I disconnect for the test?

Thanks Jeff

I think it is the right (passenger), but don't quote me on it. Either way, you can put a length of hose (1/2"ID?) on the cooler fitting and the other end in the same container.

Rooster300SD · #11 05-06-2018, 01:25 PM

Fired it up and tranny fluid came shooting out from the passenger side of the radiator towards the tranny.
I had two different gallon jugs with with hoses to catch the fluid.
So it looks like the front pump is good.
That transmission cooler line has an S curve in it. Not severely kinked.
I lost a belt not a couple of months back and it bent the cooler line metal coil.
I've driven it like that for over 1K miles without problems.

Jeff

ROLLGUY · #12 05-06-2018, 01:50 PM

If you do find out what the problem is, I would definitely like to know. That could maybe help me to fix the trans I talked about in post #3. It had the exact same issue you are having. No movement in any gear, but still had good flow from the cooler line.

chasinthesun · #13 05-06-2018, 02:12 PM

A few words as
It goes for the transmission with no gears forward, if you have reverse its either the b2 piston or a broken band. If you have no gears - shifter linkage , band itself is broken , or other.i believe I've had all the above and each was a fix or went for a know n good replacement ,that requires some trust form the seller of the used trans.

MCallahan · #14 05-06-2018, 03:55 PM

Another vote for Marc at Sun Valley. Put one of his rebuilds in my 92 300TE a month ago and it has been absolutely flawless. Only adjustment required was to dial in the Bowden cable, which took all of 15 minutes of driving. He is the ONLY trans rebuilder I know of that actually runs each rebuild on a dyno to assure it is right before it leaves the shop.

if his prices seem high, check the cost of a full rebuild kit ($350) and a new converter ($350), then figure in any bad common internal parts like bands, and such ($200), then price a new pump ($500) or drums, etc... Now, if that isn't enough... do you know the exact model of converter that fits your car? do you know the pilot nose diameter and length? I literally removed my trans, pulled the rebuild out of the box, bolted up the rebuild and drove the car. No down time at all on the trans.

I did have one minor issue with a vacuum port that was not present on my original trans that was on the rebuild. I emailed Marc on a Saturday morning and he responded within minutes, on his off day, to point me straight.

Just can't say enough good things about Marc and his work.

Rooster300SD · #15 05-11-2018, 08:11 PM

As best as I can figure, It turned out to be the kinked tranny cooler line that
caused my transmission to not function.

After I did the test for the front pump (undoing the cooler line with hoses going into gallon jugs)
and getting lots of flow quickly, I straightened out the bent coil on the line as best I could and reattached it.

I then did another test recommended by member Frank Reiner and jumpered the kickdown switch.
I fired up the car after refilling the fluid and went through the gears.
Nothing at first, then some slight clattering in R, then I could feel the tranny take hold.
Drive shaft was removed so I put it in R, looked under and, sure enough,
the flange was slowly spinning. Put it in D and the flange changed direction, spinning faster.
I then unjumpered the kickdown switch and and had it unplugged and plugged in--all with the the same results.
Figured it must be the cooler line.

Finally got everything back together today, filling with fresh Shell 134 ATF and went for a drive.
All seems well. So, the fix was a $10 cooler line instead of a $2K rebuild.

I guess the manual conversion will have to wait for another day.......

Jeff