1976 300D transmission drain plug

Where EXACTLY is the drain plug on this transmission (four-bolt pan)? I don't have the MBZ transmission manual and the Haynes manual shows a plug (forward of the pan) where there isn't anything resembling a drain plug on my transmission.

The best that I can find is a funny looking plug (half-moon slotted) to the rear of the drain pan. Is this the drain plug, and if it is what special tool is required (or what can be jerry-rigged) to remove it?

The alternative is to loosen the transmission fluid line couplings, but that drains only about 3 of the 5 quarts.

Is Dextron III ATF fluid okay (owner's manual says to use "specially tested and recommended ATF, Dextron type") or should I be using something different than Dextron III fluid?

[SW]

In my car, the drain plug is on the torque converter. You have to rotate the engine until the drain plug on the torque converter is showing through an opening in the transmission housing. I am sure this is the same procedure for your car. I think dexron III meets or exceeds the dexron fluid your manual suggests. Hope this helps.

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'82 300D Turbo 216k miles

SW,

Thanks for the speedy reply, but I believe you have a later MBZ model ('82 123?) and mine is a '76 115 model.

Are the transmissions the same on these models? I'm not even sure if mine has a torque converter.

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[SW]

I am pretty sure that all automatics have a torque converter. You are right about the cars being different, and therefore the transmissions are different. However, the differences are probably small. Do you know your trans #? Mine is 722.3, yours will probably be 722.1. The torque converter is located between the trans pan and the engine. Keep looking.

[stevebfl]

On the 722.1 tranny (you got the numbers right)in the 76, one must remove the hollow bolt attaching the dip stick tube to the pan in order to remove the pan. This acts as a drain plug to a certain extent. With the dip stick removed pull the other 4 bolts and remove the pan. Replace the filter and the pan gasket. Drain the torque convertor also.

Dextron III is suitable for also MB trannies till the 722.6.

BTW the big plug with the half moon relief is the secondary pump. Removing it won't drain much fluid, if any.

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Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician

[This message has been edited by stevebfl (edited 09-04-2000).]

Thanks to all for the information. I finally get it!

How do I turn the torque converter(?) so that the drain plug is accessible through the hole in the bell housing? What do I rotate (and how)?

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[stevebfl]

I would rotate it by turning the large bolt on the crankshaft pulley. Turn only in normal direction. If not sure watch while someone cranks the motor.

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Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician

Steve,

Thanks for the info - I've never been able to get a socket on the crankshaft pulley. There just doesn't seem to be enough room due to the closeness of the radiator/fan shroud - or I'm just too much of a klutz.

Do you have a magic way of getting at the crackshaft pulley?

Otherwise, I guess I'll rig up a remote starter.

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[P.E.Haiges]

I turn the TC with a screwdriver. Just pry between the air cooling slots against the TC housing. This way you can see when the drain plug comes into position.
P E H

[Ted2222]

Here's a tip, perhaps.

The first time I drained the torque converter, I noted and wrote down the degree reading on the harmonic balancer at the point where the drain was accessible. Thereafer, there was no problem in finding it.

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Ted
1979 240D
160,000 miles