Hello folks,

I recently aquired a 1982 240D manual. It runs well, aside from a crunch in 3rd and 1st gears. Before I condemn the synchros, I am trying the easy stuff like linkages, bushings, and fluid. I drained the fluid and replaced with Penn Sychromesh. When it was draining, though, there was a LOT of suspended bubbles in the fluid. So much it was frothy, like spit but still grey in color like gear oil:

https://ibb.co/34sYxDp
https://ibb.co/0VN7fWZ

Sorry for the crappy photos. I had to grab my phone quickly.
A few hours afterwards, when I was transferring the fluid into containers I noticed the bubbles had not popped and still suspended.

What could this be? Contamination? I'm wondering if anyone has seen this before. Thank you.

Looks like water, see if it separates in a glass jar. IIRC that transmission should use ATF. Clean, lube and adjust the shift linkages by the book after replacing the bushings, it makes a big difference.

Good luck!!!

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

Thanks SugarBear, I was thinking water too. It's not milky though, not quite mixing like that. Looking for seperation in a jar is a great idea, I'll do that.
I was thinking of trying ATF next in this box. May clean it out more, may get rid of the bad shifting, who knows...

Check the fluid used, make sure it isn't GL-5. If it is that is tough on yellow metals e.g., brass synchronizers.

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

As an aside, I just changed the fluid in mine and used Red line MTL for the first time.
Seriously smooth shifts. Even quieted down the getrag rattle. Was running Mobil 1 synthetic the last 40k miles.

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1981 240D 4sp manual. Ivory White.

Should definitely be ATF, not gear oil.

I am pretty sure my owners manual told me 10-30 or 10-40 motor oil in that tranny. That's what I just put in mine, but I haven't driven it yet to see how it does.

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1985 300 TD 448K
1984 300 TD 278K

1983 240D euro 240k
1994 f-250 idi turbo 330K
1986 f-350 IDI
1987 F-350 IDI

1985 JD 1050 4wd
1965 IH 3660

If the separator does not show water, then it could be air bubbles due to a clogged vent.
Not sure where it is located on your transmission, but typically the vent is towards the top of the case or by the shifter assembly, may be worth checking/cleaning.

Good luck.

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Stable Mates:
1987 300TD 310K mi (Hans)
2008 Jeep Grand Cherokee OM642 165k mi (Benzrokee)

Thanks Shern. I've heard great things about Redline MTL. Do the gears engage easier too? Mine take a little more force than I'd like to engage. At the transmission too.

Yeah, mine too. The 82' manual says engine oil but the 83' manual switched the recommendation to ATF.

Great point. I hadn't even thought about a vent. I'll check for one, thanks.

Much easier -and I have a fine shifting transmission including a shifter I rebuilt 20k ago. Definitely worth a shot.
I’m usually pretty agnostic about these fluid/oil debates, but this actually did make a tangible difference.

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1981 240D 4sp manual. Ivory White.

Can get water from driving through it too.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

If the gear oil drained out normally, the vent is fine. And you said you had to be quick to catch it on your phone, so I assume it was quick (for gear oil).

Look closely at differential oil, it lives in a similar environment. May want to drain and refill it to be sure.

Good luck!!!

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer