'85 300D - Leaking Transmission Fluid?
 

Front tranny seal?

That might be it. It's leaking between the seams of the transmission case. There must be a rubber seal in there that has aged.

Has anyone tried replacing these seals before? Sounds like it would be a big job.

Is that the bottom of the bell housing in your picture? Is the fluid leaking from the weep hole there? And, have you verified that it is, in fact, tranny fluid? An easy test would be to let some drip on a paper towel to verify that it is pinkish in color. IF it is leaking from the weep hole in the bottom of the bell housing, it could tranny fluid get past the seal - or - it could also be brake fluid from a leaking slave cylinder.

I've got some pictures of my transmission in the following thread

http://www.peachparts.com/shopforum/showthread.php?t=285097

I think you've got a different transmission though you can see the first of many seals in the bell housing...

Hello All,

I have determined that it is BRAKE FLUID that is leaking, not transmission fluid.

I can't tell where it is leaking from. The cylinder on the back of the transmission is dry. It appears to be leaking from above the transmission because the fluid is dripping down to the bottom of the transmission housing.

Any thoughts on where it might be leaking from?

You have 3 pipes coming from the master brake cylinder (MBC). For a car without ABS each pipe is with out joints from the MBC to the flexible pipes on the front and for the rear brakes from the MBC all the way to a joint above the differential. I don't know about cars fitted with ABS though...

My method would be to follow the fluid from the MBC downwards - if it is brake fluid you'll find it eventually if you follow this route.

post 4 got it right, good call.
have you verified the booster is dry? there is a seal on the back of the MC, and it can dump fluid into the booster, it could leak out of the seal, or out the back of the booster between the firewall. time to start searching!

There is also a line that runs from the clutch MC out of the chassis, over and across the top of tranny housing and down the passenger side to the clutch SC.

You mean it is running down from the top along the exterior of the bell housing? Or do you only see it dripping from the bottom? Where the two halves of the bell housing come together, there is usually a weep hole on the bottom. Anything leaking internally will eventually drip out there. If the slave cylinder is the culprit, you won't see it on the outside. What happens is the rubber seal that wraps around piston inside the slave eventually fails and begins leaking brake fluid inside the bellhousing - which then drips out the bottom of the housing through the weep hole.

If, on the other hand, it is running down from the top on the exterior of the housing, sounds like you'll have to follow the line up to the source.

Tank Owner,

You are my savior! That is EXACTLY what is happening. Brake Fluid is leaking out of the weep hole at the bottom of the bell housing. That's why the bottom of the transmission is soaked.

So it sounds like I need a new Slave Cylinder.

Do I need to (or should I) replace the Master Cylinder at the same time as the Slave Cylinder?

Attached are closer up pictures showing the brake fluid leaking from the weep hole of the bell housing.

Now that I know what I need, I'm feeling better about this situation.

But does anyone know where to find a w123 slave cylinder? It doesn't look like there are any in fastlane or **********.

Any other parts stores anyone can recommend?

Also, are there any hoses I should be replacing at the same time while I'm working?

Thanks!

probably won`t show a slave for 85 300D. look up 83 240D for a slave cylinder.

Charlie

Savior, huh? Well, okay - I can deal with that ;). No, seriously, just BTDT, ya know. And I didn't really know much until I bought mine and started hanging around the forum learning new things - so thank the forum.

It certainly wouldn't hurt to change the master at the same time - I think it makes sense. You can find the parts here . . . just email if you don't see them in the catalog. Glad you found the problem. . now you get to experience bleeding the clutch:eek:! You'll find what you need here. Two pointers to start with: 1) bench bleed the cylinders as much as possible before installing, and 2) bleed from the bottom up with something like the oil can method.