Changing filter and fluid in trans. - PeachParts Mercedes-Benz Forum

Gary F. · #1 03-04-2002, 11:05 PM

Read some posts regarding changing fluid/filter etc. How do you drain fluid from torque converter. 85 300D. Thanks for your help

Gary

SW · #2 03-05-2002, 08:51 AM

Get under the trans and get someone to rotate the engine until you see the tc drain plug through the "window" at the bottom of the trans. I think you need a 5mm allen wrench to loosen the plug, same size as the plug in the pan at the back of the trans.

#3 03-05-2002, 09:29 AM

Gary,

I used a big screwdriver to lever the torque converter to right spot while under car. Some discourage this approach but I was careful and it worked fine. Prepare yourself to be bathed in AT fluid unless you have a lift.

Nic

JHZR2 · #4 02-06-2004, 06:58 PM

Hi,

Im bringing this one back from the dead because I dont quite get the concept of where the torque converter is.

Its rainy and dark out, so I cant look under my car, but I have a question about something on the trans anyway.

On the bellhousing of the trans, on the underside, near the area where it mates to the engine, there is a small squarish-oval plastic cap that hides something. I was going to take it out until it started to crack, I got scared, and left it alone.

Is the thing that is under that cap the torque converter?

If that is so, theoretically, the torque convertr could be drained without ever dropping the pan?

Thanks,

JMH

Gilly · #5 02-06-2004, 07:04 PM

What that ovalish plug is for is if you need to remove the transmission, that is how you remove the 6 bolts that connect the torque converter to the flexplate (the plate that bolts tot he crankshaft). So you can kind of see the torque converter through there, but it's not what you need.
What you need is further back on the bellhousing, it's easier to see if you put your noggin back by the trans oil pan and look towards the bellhousing. It's a cast-in hole in the bellhousing. Sometimes it's just a square hole, sometimes it looks more like a cast "grille" shape with one central hole larger than the rest.

Gilly

JHZR2 · #6 02-06-2004, 07:33 PM

but so then I am kind of correct that you could actually drain th TC without dropping the pan?

I think this would be a good idea... Draining and refilling the TC about a month before doing the whole fluid and filter job, so you have a bit of new recharged detergents, dispersants, etc.

then do the whole job later, and there will be less junk freed with the new fluid, because the added power of the couple of quarts you added a month back did some of the more major cleaning already... Itll keep the new fluid's additive package stronger for longer.

Just an idea...

JMH

Gilly · #7 02-06-2004, 08:04 PM

Yeah, I mean that sounds feasable. If that's what you have in mind you could pull BOTH plugs and leave the pan attached.
A few tips:
There are 2 different sealing rings for the plugs. The aluminum one goes on the TC, the copper one is for the pan. Torque them both to 14nm (sorry I don't have a conversion for that). On that TC, make SURE you are removing and tossing the seal ring. They tend to get either reused or overtorqued and will stick to the TC. Carefully pry it off the TC with a small screwdriver. If it stays on the TC you'll get a leak, guaranteed. If it seems like you are going to round off the hex end of the plug, use a pin-punch and a hammer and tap hard in the middle of the hex to aid in loosening it. Oh, do this BEFORE you end up rounding off the hex

. If either plug is looking chewed up at all, replace them, they are cheap! Always torque them.

When you are ready to remove the pan, take note on if the bolts screw out hard or not. If they do, it is hard to get an accurate retorque, and torque is critical on the oil pan bolts as well. If they turn out hard, or alot of aluminum oxide is on the bolt threads or up in the holes in the transmission case, I recommend a shot of penetrant in each hole followed by running a tap through all 6 holes (do them all if one is bad), followed by another shot of penetrant. When reinstalling the pan, torque the bolts to only 10nm.
One of the bolt holes for mounting the pan is a blind or "dead-end" hole, I think the drivers side rear. The rest of them I believe go all the way through, just be sure to check it out first.
Another PS: If you do just drain the TC, I'd recommend draining it, then just start the engine and start with about 3 quarts of ATF (DexronIII/Mercon only), then check it. If you drain both, or when you do the "real" change, put in 3 quarts, then start the engine, then top it off, it should take around 6.5 quarts i believe with a full change and new filter.......

Gilly

(Gillyzr2 at the ZR2 site, but I don't get over there too much, can't imagine why:p

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