transmission trouble

[captainmonk]

I have been ignoring this because I dont probably want to know the answer
My transmission seems to shift fine but wont hold on a grade without a lil help with the fuel pedal BIG problem ? Or can it live like that a long time
I'm not a perfectionist if I'm not damaging it further daily it will just get older like me and all the rest of my stuff

[barry123400]

I know very little about automatics. If your idle is reasonably low and it sounds as if it is. What you describe might be normal.
This is just my opinion. Either way I cannot see any additional harm from it. I also suspect you are talking about a grade you do not have to get a laser level out to establish it is a grade. Far too much slipping would also be reflected by very poor milage and unusually slow pick up as well I would think. That too slow pickup is a little harder to gauge on these cars but if yours was truly that bad I think it would have been part of the question.

[Ara T.]

What is your idle at? Mine will hold a hill at 650 RPM.. but who cares, thats what the brakes are for.

Our old 300SDL 603 wouldn't though.. would barely crawl forward at idle on level ground without help. But I think thats how those engines are.

[captainmonk]

i get great mileage never under 27.5 under any conditions but i have to be at 700 rpm to hold a real grade I'm not concerned as long as I'm not damaging anything further to leave me stranded Dad's SDL will hold ground on the same grades

[barry123400]

Overall with your additional description I still do not feel it a problem. The only thing that may or not make any difference in my thoughts is if the transmission oil has ever been changed over the years. If it were really old and a little thinner with age it might make a slight difference.
If the fluid is still red and looks clear with no burn smell or obvious contaminates I would still leave it alone. Sometimes the transmission fluid level is very hard to read on their dipstick but again I assume you have carefully checked that as well..If by chance something was generally on it's way out the car will let you know.
I do not thing any preliminary action is possible or required as nothing is certain. You might want to talk to a transmission guy who has done a lot of these transmissions over the years. Or one may yet post. Actually the transsmission guy need not know your exact transmission to give an opinion.
Under no circumstances would I tempt fate with a flush of that transmission. Nor would I put in a really high detergent level transmission fluid at this point. Basically if it shifts reasonably well and has no tendency to flair everything is probably good. There will always be slight variations in the manufacturing process. Again I just am not really knowledgeable about automatics in general. I guess though what we are really talking about here is a slightly lesser coupling effect at idle of the torque converter perhaps rather than the transmission itself. Either by internal design or perhaps it is not quite as full of fluid at idle and that could do it. I just do not know enough about these things. Your pump is still good though or you would have other problems. I am pretty sure others with far more knowledge than myself will post. I could really learn something from your post about automatics. My last though is that if the transmission filter were somewhat restrictive at lower flow rates iit just might limit the volume of fluid available to the torque converter at low rpms. You again need a transmission guy who really knows about these things. Again I think that would also impact the general operation of the transmission though. Yet you have no symptoms at all of that.

[Mustang_man298]

Ok, if you're referring to it letting the car roll backward at idle on a hill, nothing to stress over. If you mean it starts slipping when driving on a hill, thats a problem.

What you are seeing at idle is simply the fluid not pumping fast enough through the torque converter vanes to create any real pressure in the trans, it won't damage anything. This is also called the torque converter's "stall". I don't know about MB's, but domestic trannies have many options of aftermarket converters with differing stalls, for instance, drag racers use an average of around 2000-2500 stall converters, meaning they wont engage until the engine hits 2000-2500RPM. This is done to allow the engine to hit it's power band before being loaded to the wheels. The average stall on a domestic vehicle intended for street use is 800-1000RPM.

Now slipping when driving on a hill can be caused by many things, none of which are healthy for a trans, and continuing to drive with that condition can burn up expensive internal parts.

[aklim]

Why not change the fluid? Drain the TC and drop the pan. That will tell you the problems you may face. If you drain the pan and then drop it, you can see if there is any debris or stuff in the bottom. If that looks good, drain TC. If the fluid is good and not that much debris in the pan, you are probably good. There might be some metal filings around the magnet but if there are metal chunks, you are screwed.

[pmckechnie]

I believe what he is talking about is the "Hill Holder" built into some of the MB transmissions. For instance my 84 500SEL (which has an 89 420 SEL transmission in it) will hold on a hill and not roll back. I have tried it on some perty steep hills and it will hold every time unless I pull the stick back to one of the lower gears and then the feature is defeated. I have no idea how it works but am sure it is in the trans. Will it hurt it to drive it? I have no idea, but my guess would be that it will not. This is actually a question for a Mercedes transmission specialist that is familiar with the older transmissions.

[captainmonk]

it is just holding on a hill not slipping driving I like that drive it theory