Transmission
 

OK, all. I posted a bit about this before, but now I'm totally baffled. I have a 77 240d automatic. One lovely day, I changed the transmission fluid and filter. After I was done, I had NO transmission. Nothing. Nada. I can't imagine what could have happened.

Transmission fluid level is fine. It's not leaking.

I'm working with another forum member to get another transmission, but is there anything I could try in the meantime? I mean, this is weird!

I would SO appreciate any advice.

Did you remove the plug in the torque converter? Did you put it back in? Not even sure this would totally disable it but thought I might mention it.

Do you have any ideal of how much fluid you put back in. I do not know if you could trust the indicated fluid level in your situation. The average amount of fluid needed is known if the torque converter was drained and if it was not. How much fluid did you put back in? So that would lead me to wonder if the true amount of fluid is lower than what it should be. I think for example a couple of quarts low just might produce a non functioning automatic.

Other than some form of fluke failure. The odds of it being being very low. If the transmission was operating normally before the change it should be okay. Personally I suspect you filled by the dip stick measurement only and the torque converter may be dry as the fluid level is too low to pick it up. Bearing in mind I know very little about automatics.

Posting how much fluid you installed and if the torque converter was drained or not may go a long way.

If the transmission is not actually working the torque converter cannot get fluid into it. But the static level indication on the dipstick might look normal as the torque converter is dry. I kind of assume you drained the torque converter.

You check the fluid level after the transmission has been physically operating and the fluid is hot. So basically you put in a certain needed amount and check the stick after running. Then add a little to top the fluid off. The stick measurement is possibly not a good indicator of the fluid level in your situation in other words.

I did. I drained it and replaced the plug.

How much fluid did you put back in to the transmission?

It's been a couple of weeks, but I put back exactly as much as I took out.

I thought you did as I was thinking about it. Again post the amount of transmission fluid you put in and other members will know if it was enough or you can look up the refill amount required with a torque converter drain.

If you do not remember I would add a half quart at a time. It is still better to find the required amount and compare it to what was installed though. I my limited experience these Mercedes transmissions can act a little odd with even say being a half quart low on a properly done stick measurement. Being two quarts low for example. I could not even guess.

Are you positive? Any chance at all of a measurement comparison error? Your approach was excellant if accurate. We all make misteaks though.

After verification of what you put in does correspond to the listed requirement of fluid required for a dry automatic of your type. I just looked at my Haynes manual and did not see it.

Okay found it. Non turbo automatic looks like 4.81 liters or 5.1 Us quarts. They do not specify if this is with the torque converter drained or not. I suspect it is with the converter drained though. Funny they would not specify it . Remember that dipstick could be very misleading at this point as well.

So do you remember if you put in five quarts? You should double check my spec on the quantity of fluid elsewhere though. I can make a misteak like assuming the figure included the torque converter.

I hate to add more ATF as the dipstick shows low normal. However, I don't know if the transmission is adequately heating up when I power the engine or if any fluid has gone into the torque converter.

That was my exact thought of why I figured you had drained the torque converter. You could be so low on fluid the torque converter is not being filled. Try hard to remember how much you put in.

The dip stick is pretty useless as a guide at this point but you are unfortunately using it as one to some extent. You may decide that you will have to overfill and drain the excess down if it is so later.

One way or another you still have to find out if there is enough fluid in there before going on at the same time. You can remove some later either by a suction hose down the dipstick tube or loosening off the pan bolts later.

Two last miserable thoughts. If the torque converter was not filled the level on the dipstick right after filling perhaps would normally be higher than expected. Although once again the dipstick is not to be used as a filling guide but more as a fine tuning guide after the transmission is active and warm. Running the automatic transmission if the fluid is too low to be picked up is not a good ideal either and this may be the basis of filling them by known volume initially.

I hear you though at the same time. It may be something else.

So, with all that being said, how do I ensure that fluid is getting in to the torque converter? Just add a little at a time, then siphon is off as needed? Is there another way to tell if the T.C. has fluid?

Add a little at a time. The only way to determine if the torque convertor has fluid is when the car starts to move. Once the car starts to move take it on a slow drive and take some ATF with you. If the trans shifts fine on your drive then the fluid level is OK. If not continue to add small amounts of fluid until the trans shifts OK (this is presuming that the trans shifted OK before your initial change of fluid. Once the trans is shifting OK, drive the car for about 5 miles to ensure that it shifts through all gears including reverse. Once you are satisfied that shifting is OK then let the car idle for a few minutes, check the fluid level with the dipstick while the car is parked on level ground. Remember the trans must be warm in order to get an accurate reading on the dipstick. Adjust the fluid level as necessary.

Sun Valley Mercedes Transmissions has an excellent website with lots of tips about Mercedes transmissions. They are located in Van Nuys, Ca.

OK. I've been working on this for the last hour or so and I'm up to the nearly full mark and NO movement at all.

I'd double check the linkage..old worn bushings and clips may have let a rod pop out possibly while working on it. Besides that, I'd have that pan off again and look at it for anything unusual and just to ensure the filter is aligned right and then back on & add more fluid to mark.

FE240D's advice is excellent. Check that the linkage is actually allowing the trans to shift into gear - forward and reverse. Also his point about ensuring that the filter was properly installed is also a good step, it is also a good idea to check to make sure a piece of foreign material did not become lodged in the filter blocking flow.

For all those who are now consulting with elcaBob, read through this thread, it is the first part of the saga now playing (at selected theaters) in the current thread:

http://www.peachparts.com/shopforum/diesel-discussion/378755-tranny-done.html

There are indeed some extra plot twists.