Thanks for the thoughtful reply Nate!
There is indeed a light clunk every time I press the clutch, which sounds similar to a bad throwout bearing in my NC miata years ago. But, we will see.

This weekend, I will be replacing the slave, the tranny oil (into a clean pan!), and then making an adjustment to the transmission mount. When I replaced this mount, the metal tube had to be jammed into the crossmember to fit. In hindsight, I realized this could be a great place for vibrations to be transfered to the body. I will report back!

It's tricky to diagnose sounds over the computer, I hope this turns out to be a simple thing .

In general if the noise stops when you depress the clutch it's a tranny issue .

*general* .

Don't forget the magnet ! .

If you have to jamb the center mount in it's wrong, maybe your two side mounts are collapsing .

I just had to replace both in my '82 240D and they were factory mounts, maybe four years old and _never_ allowed to touch oil .

They just settled a bit .

There's a LOT of adjustment in the center mount .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Think you may be confusing the T-mount with the center mount.

The center mount screws directly into the transmission. It’s then held to the cross member by two 13mm bolts. Nothing in the way of adjustment.

The T-mount (flimsy rubber thing from the oil pan) has a page in the FSM about adjusting.

__________________
1981 240D 4sp manual. Ivory White.

Nate, I did just replace my motor mounts with lemforder mounts, so all engine mounts are now new. The transmission mount (which you call center mount, I’m not sure what’s the better name) was jammed in because the circular stopper tube was too long. I believe the mount was manufactured incorrectly, or perhaps my crossmember is bent. I found another peach parts post from long ago where another person was having my exact issue, and he solved his issue by removing that metal tube. We will see.

Shern, there is indeed some adjustment in the center/transmission mount. There’s a 5 or 6mm hex bolt that slides up and down. I’m still not certain on it’s purpose.

Actually I was talking about the center mount under the engine .

The rear tranny mount also often degrades from being soaked constantly with Diesel contaminated engine oil .

The rear mount is also *slightly* adjustable but the vibrations usually are from the center mount under the engine due to careless assembly .


Keep at it you're nearly there .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Yes, that is called a T-mount: 1232400365
And it is adjustable.

The center mount is not, unfortunately.

__________________
1981 240D 4sp manual. Ivory White.

Interesting… I do not have that on my 81

__________________
1981 240D 4sp manual. Ivory White.

Sadly I don't have access to the E.P.C. else I'd use it to copy and paste images and part numbers .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Folks, reporting back. Yesterday was a GOOD day.

1. Discovered that as I suspected, the clutch slave was leaking INTO the bellhousing. See the old part here: https://imgur.com/a/IjtQBXX
Replaced the slave, and bled with my oil can. Holding pressure so far.

2. Drained the old transmission fluid. Looks like it was dark, old, ATF. There was a little bit of light grey color here and there, not too much. Measured how much came out, and it was underfilled - only a quart came out! (as opposed to 1.5 quarts) Refilled with Redline MTL, and now most of the bad noises are gone! Particularly the noise I filmed a video of, is gone. Transmission shifts very nice, with no grinding at all. Regarding it being low on fluid, hopefully that was PO user error, and not a leak somewhere...

3. On a hunch, removed the transmission mount I replaced a few weeks ago. As I said before, the stopper tube had to be jammed into the crossmember, and I thought maybe that's where vibrations traveled. I replaced it with a different style of mount that fit better, and that fixed the vibrations!!

Some notes:
-Thanks to Nate & Shern for encourging me to try these things first, instead of going crazy and dropping the transmission. I am excited that all these major issues were fixed with relatively simple fixes.

-While the clutch slave was out, I took the opportunity to boroscope the pressure plate. There was some discoloration on the springs (from the brake fluid, or maybe that's normal?) but nothing else out of the ordinary. See poor quality image here: https://imgur.com/a/Z5js3FT

-Shern, here is a photo of the crossmember: https://imgur.com/a/TzTPfBS you can see that oval hole in the middle where the stopper bolt goes. It can be adjusted up and down a little bit, maybe to account for wear? Just for your reference. This car is an 82', so your 81' may be different.

Thanks again all. I can now focus on other smaller issues on this car, and start to drive it finally.

Nicely done!

I'm curious about that mount you swapped out.
Do you have any A/B photos?

Wild it could make such a difference...



-

__________________
1981 240D 4sp manual. Ivory White.

Thank you! You were a big help.
The original mount I used, was this one: https://imgur.com/a/QBxAaa1
The second mount I used, was this one: https://imgur.com/a/8YEupj0

They are identical, aside from the stopper tube inside. As I mentioned before, the issue wasn't the rubber, but that the stopper tube in the circular style mount was jammed into the crossmember, essentialy bypassing the rubber entirely.

Had I modified the first mount by removing the stopper perhaps, it probably would've worked fine.

I wanted to use the oval mount, however, because it was a Febi part and hopefully a little better than the circular Uro mount, the only brand I can find for that part number.

It should be noted that these mounts seem to interchange perfectly, and I'll probably just use the oval one for all manual transmission cars from now on. Easier to find, and better brands manufacture them. The auto trans mounts are easy, only one style to pick from without the stopper tube.

Thanks for coming to my Ted Talk.

Nice to hear it was a fairly simple fix .

I hope you remembered to add a magnet to the drain and / or fill pugs ~ SWARF is a very bad thing indeed and a simple $6 magnet stops it .

Because there was some grayish crud in the tranny fluid I'd highly suggest driving it 500 miles and draining / refilling it again, this will also give you the opportunity to see how much SWARF the magnet collected or to add a magnet if you didn't yet (bad boy) .

I also hope you took the time to remove the brake fluid resivoir and clean it really well ~ that black dripping stuff is old brake fluid contaminated with rubber bits and moisture .

Remember : only brake cleaner, alcohol and brake fluid are permissible to touch the inside of the hydraulic system ! .

Don't sweat the blue clutch cover fingers, it will let you know when it's bad .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Thanks for the input and help Nate!

I was unable to find a magnetic drain plug in time, so I haven't done that yet. Can I just add a magnet to the end of the normal drain plug? Perhaps with some glue, let it dry before refilling. Draining and refilling in 500 miles makes sense, I was planning on doing exactly that with the engine oil too.

I also need to fully bleed the brake system, so I'll clean the brake master cylinder when I do that too.

I managed to reseal the badly leaking power steering pump yesterday, so I was finally able to take this lovely car for a long drive. All the hard work is finally paying off!

Once I deep clean the interior, I'll be sure to post some photos here if anyone is curious.

Yes, it will stick to the tip of the oil drain plug, no glue .epoxy necessary .

Did you replace the big O-Ring too or just the input shaft seal ? .

Not having that drip is very nice indeed .

You may find you'll need to change the power steering's ATF a few times before the burned smell and dark color remains gone .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Please do!

__________________
1981 240D 4sp manual. Ivory White.