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Discussion Starter #1
I've got a 1990 300se 200kmiles

The trans runs very smooth for its age. No rough shifts or revy kick downs. The ATF fluid looks fresh, a clear red color.

When I check the ATF as per manual instructions (letting it idle for 2 minutes on level ground then checking) I get a proper 68-86F Shop reading. The fluid line is just below the lower mark. About 10mm below the minimum mark. The manual says that is fine for that temp.

When I check the fluid at normal operating temps (after driving for 10 minutes checking on level ground and engine running as per forums instructions) the fluid level shoots way above the maximum mark! About two inches above the max (80C) mark. I've read that ATF expands when its hot, but this mark is just way too high. The manual says to drain or siphon the excess fluid.

I've yet to put the 300se up on ramps. Is the transmission drain plug easy to get to? Where is it located? Should I replace the ATF filter? Is there a PDF on maintaining the transmission?

best regards
Kevin
 

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Sometimes it is hard to read the dipstick with the car hot and running. The fluid splashes around and is all over the stick. Also, fluid in the tube gets all over the stick as you put it in and withdraw it. You have to look very carefully at the stick to see the point at which the fluid is across the stick, and not just running on to the sides. And it may take a few redings to get one that is conclusive. It is very unlikely that with the cold level right, you are that far off. The difference between min and max is only about 0.4 liters, so to be 2 inches off would be a lot of fluid. Check it again, get the fully up to temp, then let the car idle for a few minutes on level ground in P and then see if you can get a good reading. Charlie
 

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Drain plug is an allen head bolt in the bottom of the pan, 5 or 6mm I believe. If you want the trans pdf, PM me your email and I'll try to send it to you. It was too big to post on this list before when I tried.
 

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Discussion Starter #4
Thanks for the info Charlie and Mark. I'll PM ya, thanks!

I thought two inches too high would make the car basically un-drivable.

I just got the car a few months ago, so I figure a complete fluids change would be in order. The ATF looks fresh, so I thought I might be fine there, but if I cannot tell how much ATF is in it, I should change it.

I just got back from the mcparts store and could not find any Dextol III, just some mcpart brand that said it is a "suitable" replacement for Dextol III.
I've read here that DextolIII is what I need, but those posts are so old... now its up to Dextol V. Is that stuff ok to put in the transmission?

Should I also put in a bottle of Lucas Anti-Slip and Transmission Conditioner? Or is that stuff a waste of money?
 

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Discussion Starter #5 (Edited)
I just checked the ATF dipstick with engine cold and it is giving me the exact same fluid reading as when the engine is hot.

I just checked per Charlie's instructions above and actually got a good reading. Thanks Charlie!
 

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Dexron III/Mercon is the recommended stuff. The Dexron and Mercon licenses are woned by GM and Ford, and are no longer licensed for use on Dexron III/Mercon stuff (only the higher numbers). So you are looking for ATF that says that it is for use in cars previously serviced with Dexron III/ Mercon. (Pennzoil and Chevron make this, avialable at Walmart and costco, etc., as do many other companies.) Some use synthetic, but it is not recommended by MB. To get a hot reading, yoiu really have to warm the car up. Maybe 20 minutes of spirited driving. Depends on ambient temp. Do NOT put any additives in the ATF. A transmission service includes a new filter and gasket, and the 2 seals for the plugs. You need a 5 and/or 6mm hex bit, and a good torque wrench. And read the manual on how to do it!! Charlie
 

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Discussion Starter #7
Thanks benzwag. Thats great info!

Does anyone have the pdf for transmission service?

The one Markus sent me was a bit over my head, it involved transmission removal and installation.
 
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