I have two items I would like all your help with. The first is how to properly adjust the 1977 automatic transmission. I was going to go thru all the vacuum items I have read about here, but just saw that the vacuum controlled transmission didn't appear until 1978.

Next, this is more of an opinion. I am not aware of when the previous owner changed the fluid and filter. I have a new filter and plan on draining the trans and torque converter. Should I change the filter? I have read/heard information on if your trans is slightly worn, the somewhat plugged filter is giving added line pressure to the system, therefore the new filter will cause future slipping. Fluid replacement is also the question. I have read people say only use MB trans fluid, but then others have said Dexron III. I currently have some Valv High Mileage Dex III, good idea? Also is using Seafoam trans tune prior to doing the job and also Lucas auto trans additive when replacing fluid? The current fluid is still nice and red and doesn't have any burnt smell. But I would still like the information even if you guys say not to change it based off of the condition of the fluid. I would like to do it so I know when it was done for future reference.

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Tony
1977 240D WVO converted

Just my opinions and beliefs. Others may feel diferently and I might be wrong as well. The transmission filter if obstructed would tend to starve the pump of enough fluid. A filter is to catch wear particles primarily. Since it is on the suction side of the pump I can see no real advantage having it obstructed.
In fact pump cavatation a known damaging pump factor might get underway to some extent. Your filter for example may still be good but an unknown at this point. Your transmission fluid is not burnt and full of particles. Sounds like the old filter has done it's job. My main thrust here is I can think of no reasonable way a dirty filter can increase hydralic operating pressures.
I had a good automatic transmission guy once tell me that older mercedes internal seals tend to dry up so to speak sitting around unused for long periods of time. This needles to say results in pressure reduction or slow responding functions. The leakage has to be overcome first in any operating paremeters. So before dropping a transmission off for faults like late shifting or flairing treat the transmission with a treatment to try to expand the seals. I imagine that is one of the functions af most if not all transmission additives. Basically a petroleum oil makes rubber seals expand.
He also told me that it is advisable to drive the car with the treatment at least 1500 miles before deciding anything. Since you have the earlier transmission probably reading all you can about it might help as well.
I think you are underway with that. I also own one of those transmissions in a 1977 300d. It seems fine thank goodness. Perhaps most mechanical things live in fear of me.
One more last thought of mine is on most these used cars the transmission fluid has not been changed out on a regular basis. I would not introduce an aggressive high detergent type of fluid. Instead I would do a little research into finding an acceptable rated fluid that was the lowest rated for detergent activity.
Like the questionable process of flushing an older transmisson. Sometimes not disturbing it more than neccessary is on the safer side. Just some of my beliefs but I could be swayed by superior knowledge or experience.
I think if you were just changing fluid as a maintenance item on a good working transmission this last paragraph is really worth thinking about. Once trouble is underway if you feel the valve body needs devarnishing for example or sludge cleaned out of the valve body then a high detergent oil might be better. Always try to locate and discuss concerns with an able and honestly interested transmission guy if possible. Their experience is worth it's weight in gold if like myself you do not possess very much knowledge.

You are correct in that the 77 does not have a vac controlled transmission.
It has a long rod extending from the pass side of the trans up to the throttle linkage under the intake manifold. There is rubber bushing on the trans side of the rod that is common to failure. This can cause early or late shifting because the rod not being held in it's proper position.

There is also a adjustment on the rod near where it connects to the throttle. Real picky adjusting it... 1 or 2 turns one way or the other can make all the difference.

__________________
"Any sufficiently advanced technology is indistinguishable from magic"
-Arthur C. Clarke

"I won't be wronged. I won't be insulted. I won't be laid a hand on. I don't do these things to other people. I require the same from them."
--John Wayne.

OBK member#16
77 300D
75 300D (rusty parts car)
73 220D (Dad's)
98 Jeep Grand Cherokee
82 Kawasaki M1

Well I guess the bushing will be my next purchase. How does the adjustment affect the shifting? Firmer/Softer or Earlier/Later shift points? I did notice a difference in the shifting when I tightened up my throttle linkage. Not to mention the throttle was opening all the way. I think I might have gained 1 whole h.p.!! But with a 240D, I'll take what I can get.

I still didn't get a definitive answer on the Valv Dex/Merc High Mileage trans fluid...good...bad...ugly...??
Thanks again

__________________
Tony
1977 240D WVO converted