Tranny took a dump today..... - PeachParts Mercedes-Benz Forum

Plantman · #1 10-08-2004, 08:39 PM

Started my SDL up today, everything seemed normal.

Stopped at a traffic light and felt the car sort of shift. Gave it some throttle and nothing. Moved the shifter to P N R, etc.. and the car was in reverse in every gear.

Had to back up into a service station. Waited a few minutes and it went into drive. Drove it about 2 miles to the indy and it shifted well, but I heard a whining noise. By the time I got to the indy, it stopped going fwd. Shut it off again, started up and made it in.

He tells me my tranny is shot, but that it might not be so bad as it didn't get driven that way for long.

Frustrated, to say the least. The car was shifting fine.

I have a tranny from my SD, but am unsure if they are interchangeable.

Any thoughts on what happened?

Tirebiter · #2 10-08-2004, 09:05 PM

You owe it to yourself to put Trans-X in it, drive it a bit, and change fluid and filter. Don't forget to drain the converter also. Would be a good idea to check pressure at the modulator also.

The problem you describe could be caused by a gummed up valve body. It could also be caused by internal leakage due to worn parts.

Hatterasguy · #3 10-08-2004, 10:41 PM

Well it did last 330k+ miles, but try the trans X first. If I remember correctly the fluid was changed on that one.

turbodiesel · #4 10-08-2004, 10:45 PM

Strange you would have a sudden failure like that.. MB trannies usually take a long, slow road to death. I changed the fluid in that car regularly and it always shifted flawlessly. I would try trans-x first before you go for a rebuilt. I think www.germantransmission.net has rebuilts for around $1200 with core.

EDIT: The site says the 81-85 300SD has a 722.315 while the 300SDL has a 722.321. I doubt they are interchangable.

Hatterasguy · #5 10-08-2004, 10:55 PM

Differant engine so differant gearing probably.

pwogaman · #6 10-08-2004, 11:30 PM

Here is a good explanation of how the automatic transmission works:

http://auto.howstuffworks.com/automatic-transmission.htm

There are several pages you'll need to go through to see the whole explanation. Just don't forget to hit the "next" button at the bottom. Pretty neat moving graphics.

There is an outfit in L.A. that overhauls MB xmsn's exclusively. I think their prices are a little better than that mentioned above. Their link is:

http://www.mercedesdismantlers.com/

It sounds like your B2 valve is sticking or close to breaking. I've read of others replacing that valve mechanism without totally removing the xmsn. It might be work looking around.

mplafleur · #7 10-09-2004, 12:00 AM

I had these guys rebuild my SDL transmission.

http://www.europeantransmission.com/europeanhomepage.html

They are very good and located just north of Atlanta in Cumming, GA.

TwitchKitty · #8 10-09-2004, 07:16 AM

There is a specific troubleshooting flowchart for each automatic transmission. Driving a car with a malfunctioning automatic transmission is a sure way to kill the transmission. Park it immediately until you can run it through the tests to see if it is salvageable.

If you have made up your mind that you won't get your transmission fixed and will replace it then you can't loose anything with the trans-x.

There are individual books for each transmission called tech guides, I don't remember the name of the company that sells them. The tech guides usually sell for $15 or so. There are other professional manuals like Mitchell that you may gain access to.

Plantman · #9 10-09-2004, 10:17 AM

I would try the tran-x , but it won't last more than 1 mile before it "focks up".

Like I said, seems strange as it was running fine with no symptoms prior to yesterday.

JerryBro · #10 10-10-2004, 12:51 PM

Get the rear wheels off the ground, add the TransX, start it and run it in reverse for a while, then run it forward. If it stops, put it back in reverse. There could be some schmutz in the valve body, or maybe some pump/governor issues.

The B2 piston engages brake band 2 when the car is in 1st thru 3rd. In 4th it is disengaged and clutch K2 is engaged. When this piston fails the car usually won't go forward at all. The B1 piston is only used for 2nd gear. Reverse uses the B3 brake (which looks like a clutch pack to me, oh well).

What is interesting is that it stayed in reverse, makes me think there are valve body issues or some kind of strange pressure issues. Does the fluid look ok?

Plantman · #11 10-10-2004, 11:46 PM

Tranny fluid looks fine, did service about 7000 miles ago, it was clean then also.

As far as trying tran-x, it won't run for more than 1 mile before it goes kaput, so I doubt it will help at all.

We'll see this week. The indy says I may have caught it in time to not have done major damage.

Wish me luck! :p

bill murrow · #12 10-11-2004, 07:53 AM

Quote:

Originally Posted by pwogaman

Here is a good explanation of how the automatic transmission works:

http://auto.howstuffworks.com/automatic-transmission.htm

There are several pages you'll need to go through to see the whole explanation. Just don't forget to hit the "next" button at the bottom. Pretty neat moving graphics.

There is an outfit in L.A. that overhauls MB xmsn's exclusively. I think their prices are a little better than that mentioned above. Their link is:

http://www.mercedesdismantlers.com/

It sounds like your B2 valve is sticking or close to breaking. I've read of others replacing that valve mechanism without totally removing the xmsn. It might be work looking around.

A friend of mine lives in LA and has seen the tranny shop you're talking about. His opinion of the shop was not good. Said the place was filthy.

Personally I've never been there, don't know anyone who has had their tranny rebuilt there either. I do know on the tranny dipstick it says to use a "lint free" rag to wipe off the stick so a dirty shop won't help matters any.

Cheers,

Bill

Rick Miley · #13 10-11-2004, 11:45 AM

Quote:

Originally Posted by Plantman

As far as trying tran-x, it won't run for more than 1 mile before it goes kaput, so I doubt it will help at all.

That may not be necessary. I'd search for Leathermang's original story about Trans-X, but he's mentioned it about 100,000 times, so it would take a month to find. But from memory, it acted very quickly. Like before he got out of the parking lot. You can put the stuff in, start the engine and just shift through the gears without the car moving. That still circulates the fluid through the valve body. The hardest part may be convincing the mechanic to let you try it.

Pete Burton · #14 10-12-2004, 12:11 AM

yeah, Greg loves that stuff so much, I hear he puts it in his morning coffee

MBDFahrer · #15 10-12-2004, 03:51 AM

Should Trans-X be used on a routine basis? Sort of like Diesel Purge for the injectors? Maybe once every 60,000 miles or something? My transmission just delays when putting it into gear and was wondering if i should just get some trans-x and flush the system. The fluid isn't that old either, about 6,000 miles on it (Chevron ATF).