Hey all,

Recently purchased a 1988 420SEL. While I still love it, its cost me a fair bit already in the first month. Firstly:

Radiator leaked which caused tranny fluid and coolant to mix. Had new radiator put in and also coolant and tranmission flushed.

Car started to leak fuel into the oil which meant it needed a new fuel distributor and also fuel pressure regulator as well. It smoked like hell and now has a rough idle which it didnt have before. Engine oil and filter replaced.

Now to the point, the transmission used to shift real early. So I adjusted the bowden cable and its much much better now. The only thing is, sometimes I can drive normally and give it some stick and it will shift fine. Other times If i drive normally, it will shift up fine but if I downshift it refuses to shift back up and it only will shift normal again if I put it in neutral and then back into drive. Seems to hesitate to shift up after some spirited driving. Shifting it back to neutral then drive seems to erase memory and it drives normal again. Sometimes it will drive a whole day and not play up.

Ive checked the vacuum lines underneath and seems ok and also wiggled the modulator a bit. Ive ruled out it needing a flush as this was done with new filter. It cant be sticking valves because it shifts perfectly after putting it in neutral then drive. A vacuum leak would mean it would ALWAYS hesitate to shift up not sometimes right?

Does this basically mean a faulty modulator or something else can I check?

Thanks

 

pull the vacuum hose off the modulator after driving and see if you see any trans fluid coming from the hose or modulator.
Dave S.

 

I have the same problem. Were U able to identify the problem? What was the fix? How much did it cost U?
Thanks.