doing some maintenance... - PeachParts Mercedes-Benz Forum

E150GT · #1 10-27-2011, 11:10 PM

This weekend I am going to attempt a few maintenance items on the SD. I am going to replace the transmission fluid and filter as well as the diff fluid and power steering fluid and filter. I have a few questions as I want to get this right the first time.

Transmission- I dont know when the fluid was changed last or if it ever was. The car shifts fine if that means anything. Should I use regular fluid or synthetic? I dont know if it the same as motor oil but my transmission does not leak and I want to keep it that way. Also is it imperative to change the fluid in the torque converter? I read where you can drain it but if the fluid does not come out of it when you drain the pan, how the heck can you fill it back up?

Diff fluid- This should be easy but what fluid to use?

Power steering- I have read a few disputing articles on this. Mainly the differences being that some state the car has to be on the ground and others say it needs to be on jack stands. What do you guys think?

After these larger services I will just have to put on a couple of fuel hoses to complete my weekend wrenching. Next week brings a new monovalve and wipers and a hood pad. After that I need to flush the brake fluid but I think I will have my mechanic do that when I finally get it in for a valve adjustment. Then I suppose new shocks and motor mounts couldnt hurt. Sigh Im broke already. Thanks for the replies..

sixto · #2 10-27-2011, 11:28 PM

Transmission = regular vs synthetic ATF is a personal choice. How I fill the transmission = I pour 5 quarts through the dipstick tube, start the engine and run through the gears. If reverse engages, I back down the ramps. If not, I leave the engine running and pour in another cup, run through the gears and see if reverse engages repeating until reverse engages. On level ground, I run through the gears again and check fluid level and add in cup increments running through the gears and checking the fluid level until the fluid is about 1cm below the min mark on the dipstick. At that point I go for a 20 miles drive. Not creeping in traffic, 20 miles of proper running. Then I check that the fluid level is between and min and max marks on the dipstick, topping off as necessary. If the fluid is too hot to leave your fingers pressed on the wet tip of the dipstick, it's close enough to 180*F for a hot reading. I'm not one to have fluid at the max mark. I prefer to keep things in the middle.

Differential = I believe the open (non-LSD) diff takes 75W-90. Definitely go with synthetic since you're not going to replace it for a while. Remove the fill plug before you remove the drain plug. Check the condition of the diff mount. There should be an air gap between the mount frame and the part that bolts the diff cover. If there's no air gap, the mount is shot. OE mounts have a bump on the lower surface of the mount frame. If the bump is worn flat, it's time for a new mount.

Power steering = I prefer to flush the power steering system with the wheels off the ground. I figure I might damage something if I turn the wheels against pavement if the system runs dry. I find it difficult to fill the reservoir as quickly as the pump spits out fluid. I believe for the 1984 vintage you have a choice of ATF or power steering fluid. I prefer power steering fluid because it's easier to tell when the old stuff is purged and it's easier to monitor clear fluid as it ages.

Sixto
87 300D

E150GT · #3 10-27-2011, 11:43 PM

Quote:

Originally Posted by sixto

Differential Check the condition of the diff mount. There should be an air gap between the mount frame and the part that bolts the diff cover. If there's no air gap, the mount is shot. OE mounts have a bump on the lower surface of the mount frame. If the bump is worn flat, it's time for a new mount.

Sixto
87 300D

I will take a look at that mount but let me tell ya, I am not looking forward to replacing that. I did it on the 420 and it was probably the most difficult thing I did on that car. I must have done something wrong because for the life of me I could not get the bolts to line up. I think we got three bolts in and the last was not having it. I got tired of messing with it and it was late and I had to use the car the next day so I took an impact and made that last bolt go in. I dont want to do that again.

toomany MBZ · #4 10-28-2011, 08:26 AM

On the transmission, rotate the engine so the drain plug is visible from under neath and drain it (torque converter) too.

Filling it up via sixto's description is what you want to do.

E150GT · #5 10-31-2011, 10:25 PM

Quote:

Originally Posted by toomany MBZ

On the transmission, rotate the engine so the drain plug is visible from under neath and drain it (torque converter) too.

Filling it up via sixto's description is what you want to do.

How can I get the engine cranked over?

engatwork · #6 10-31-2011, 10:28 PM

27mm socket on the crankshaft pulley bolt. Only turn in the direction that the normally turns.

E150GT · #7 10-31-2011, 10:47 PM

Quote:

Originally Posted by engatwork

27mm socket on the crankshaft pulley bolt. Only turn in the direction that the normally turns.

Thanks. I am assuming clockwise?

pawoSD · #8 10-31-2011, 11:28 PM

Quote:

Originally Posted by E150GT

Thanks. I am assuming clockwise?

correct. Rotating towards the drivers side when standing in front of the car looking at the engine.

leathermang · #9 11-01-2011, 12:19 AM

Follow Jim's advice..which is the same as the FSM...
DO NOT be tempted to use the nut on the power steering pump...
as that is a taper fit and can ruin the shaft.... big money if you ever need to deal with it...
Crank Bolt is perfect.... might take a short extension and might need to put in the items one at a time if your fan is close by....

leathermang · #10 11-01-2011, 12:24 AM

There have been some pretty smart ( otherwise ) people who have assumed that the fill plug was going to open up like it should ...and drained before checking... made for some funny reading...
If it is stuck and you have one of those factory bent tools with the different size allens on it.... that can be put into that filler plug... and a comealong be run from it to a rod in the jack up hole in front of the passenger side rear tire.... for a controlled large force application... pics in the archives under my name...

vstech · #11 11-01-2011, 08:52 AM

... if it's stuck, heat does wonders...

E150GT · #12 11-06-2011, 09:09 PM

Ok. Since I didnt get a chance to perform all these actions until today. Changed the power steering fluid and diff fluid today. No problems there. By the way there is still an air gap on the diff mount. I drained the transmission today and the fluid looked orange and watery. I figured it might have gotten water in it when I drove through that high water a few weeks ago. I replaced the filter and gasket and filled it back up. It only took three quarts to fill it up. I thought it would take more. I decided not to drain the torque converted just yet. Well fast forward to tonight and I decided to check the fluid when I got it home and now it is that same watery orange fluid again. I know there is some more fluid left in the lines and torque converter but I didnt think it would make the rest of the fluid milky like that. Or am I wrong. Now I got to thinking about how I can take the radiator cap off when the engine is hot and there is no pressure released. I guess theres a couple if possibilities here:

A: The radiator cap is faulty and the milky orange fluid is from mixing with the unchanged transmission fluid.

B: The radiator where the transmission fluid is cooled is compromised and allowing coolant into the transmission.

I have looked in the coolant reservoir and although it has the green coolant, it looks and smells just like coolant with nothing mixed in. Also the transmission is not overfilled so I am not really sure what to do now. A cooling pressure test would reveal a leak but would not pin point where.. What would yalls course of action be?

engatwork · #13 11-07-2011, 06:32 AM

I does not take much contamination to discolor the fluid. I would suggest draining the torque converter, hoses, pan, dropping the pan, dropping the filter and then put it all together and try again. Disconnect the hoses at the cooler and see if you can seal up one port while putting compressed air on the other to see if you can hear it leaking internally.