W123 transmission

[Mr Livered]

Hello - first post from a newbie.

I recently bought an A-reg 200T which has been great so far. However, since this is both my first Merc and my first automatic car I suppose it's inevitable that the first problem would be with the transmission

Basically, it's losing fluid; I try to keep it topped up but to be honest I find it incredibly difficult to read the level - I just see smears on the dipstick - and periodically I find whilst driving that I can feel the fluid's getting low - which can't be doing the box much good. Yet I can't see any sign of a leak.

Can anyone help with ideas of how I can find/stop the leak? Or should I be looking for a new box?

Many thanks in advance.

 

[TimN]

The first task is to identify where you are losing the fluid from. I will wager that you are losing it from the torque converter. You will see oil dripping from the heat dispensing grills below the torque converter. If so then just make sure that your drain plug in the convertor is tight. If so then you probably will have to change a seal. Alternatively, you might be over filling the system. Don't forget that you only test the oil level with the engine running.

 

[Mr Livered]

Thanks very much for the reply.

 

[eric242340]

You say, cant find any signs of a leak, and you find it hard reading the dipstick. Are you checking the level with the engine running as posted by Tim? Also you feel the transmission is loosing fluid, why do you feel this. Does the transmission misbehave in any way? Does it change smoothe at approx 2500 rpm? Is there any fluid on the floor of your parking space? Sorry for so many questions, but im just trying to understand your thinking, thanks Eric.

 

[Mr Livered]

Thanks for that - and I'm sorry I have taken so long to come back. Yes, I'm quite sure the fluid's getting low even though the dipstick isn't easy to read - lots of jerky changes and when I let it get really bad I started to lose drive altogether - some more fluid helped. I'm just feeling like a right pillock because I'm a newbie with automatic boxes and I don't want to trash my first one!

After reading Tim's post, yes, there is some reddish fluid under the torque converter, but not enough to make a mark on the floor - just enough to coat it at its lowest point - is it possible that it is being forced out only when driving?

 

[television]

Thanks for that - and I'm sorry I have taken so long to come back. Yes, I'm quite sure the fluid's getting low even though the dipstick isn't easy to read - lots of jerky changes and when I let it get really bad I started to lose drive altogether - some more fluid helped. I'm just feeling like a right pillock because I'm a newbie with automatic boxes and I don't want to trash my first one!

After reading Tim's post, yes, there is some reddish fluid under the torque converter, but not enough to make a mark on the floor - just enough to coat it at its lowest point - is it possible that it is being forced out only when driving?

If it was being forced out while driving it would still drip when you stop, as the fluid to a fair degree would get picked up onto the flywheel. If you are having difficulty in reading the stick,why not ask a garage man to read it for you when it is hot.

 

[Amphiscian]

Might be worth getting the filter in the gearbox changed. They can become blocked, causing symptoms like yours. Hard to take a reading of the level if the fluid is not flowing through the box freely, so you may be overfilling?

 

[Mr Livered]

Aha! Sounds like a good idea - if it needs a new filter that might make me fel a bit less incompetent for not being able to read a dipstick. I was wondering if it was me who was the dipstick

 

[wscheffer]

Check the modulation valve. Their is a vacuum line that connects to it. Often when these go bad "usually the diaphragm" they will suck the fluid from the transmission. This will cause the fluid level to drop in the transmission without leaving a noticeable trace.

If you pull the vacuum line and there is fluid in it well...

 

[eric242340]

I think you have a problem, but first check the fluid level correctly. ie engine running and at least 80 degrees temperature. dipstick out and wipe and dipstic in , then check there are two notches on the dipstic and the fluid level should be above the lower notch.

 

[dwayneb]

Check the return line from the transmission cooler. Mine had a crack in the rubber hose and it really only leaked when the car was in gear and moving. I was looking for my leak and found the crack almost by accident. It was right where the line passes through the bracket near the oil pan. Mine is an American 300D if that makes any difference.

 

[eric242340]

Well, sir did you find the problem or is it still ongoing? Im sure people here would be interested in the end result.

 

[Mr Livered]

Well, sir did you find the problem or is it still ongoing? Im sure people here would be interested in the end result.

Well, sorry I didn't reply earlier - it was because I have been to Cornwall - in the Mercedes... 700 miles and no more problems (well, I did have a burst tyre and a very rumpety-pumpety engine which made me scrabble for the nearest motor factors for a new distributor cap - simple stuff).

So I'm happy but still confused. Either the problem has just gone on a temporary leave of absence or (hopefully) I've cured it by accident whilst poking around tightening things up.

I'll let you all know if it starts leaking again I've appreciated the time and effort people have put into posting.