o.k. im new at this typing thing so im not the best. i am the proud owner of an 81 300CD with, get this 68,760 ORIGIONAL MILES on it!!! thats the good news! the bad news is it really was neglected. it had 16 oil changes ( my best guess) 5 of which i did in the past year and a half, never had the rear end or transmission fluid serviced, and had the radiator fluid changed once. but it is a beautiful car to look at. reminds me that jessica simpson and brittnay spears is the best music i have ever seen! so here are the problems i am having as a result. about a year ago the transmission started to get lazy and would not shift the same. now it shifts only when the maximum shift points are reached. by max i mean if the throttle were held to the floor through all three shifts it works like it should. but you can creep up on max and it will not shift until it HAS to. example: drive normally to 55 mph and the car stays in third gear and would go in third for weeks or until approx 62 mph is reached and shift. then in fourth i can slow to 40 mph and lean 3/4 or better into the pedal and it will just cruise right back to 65 and not have to down shift to do it. if i force the downshift it does it but it is usually not required. it never was usually required. the shifts are fine if i just put the car to the floor but if i come to them slowley the car is jerkey, as some of you might imagine. in other words it is not slipping and the shifts are very positive. i was leaning toward vacume problems and have replaced those tiny vacume levers and i have the modulator valve and dashpot to replace the old origionals. i need to know if i am going in the right direction and how to set the aftermarket modulator valve upon installation. the car was my mothers who recently passed on and i would really like to keep it. i am an above average mechanic but i am below average at trouble shooting automatics or trannys period. if i should give up now and go to a shop would you recomend dealer only or foreign independent shop. any help is really appreciated and as far as i can tell this car is going to be beautiful when the valves are adjusted, injectors cleaned and some general maintenence is done to it. thanks andrew f.

 

you have to check the modulating pressure first before replacing it.

does it got B-Switch?

the governor pressure is good? the working pressure is good? the control valve linkage is on correct position?

 

i am going to check pressure at the modulator. what is b-switch? and i do not know if the working pressure is good. the control linkage hasnt been touched and all the connections appear to be tight, or i dont know would be the correct answer. is checking gov and working pressure something i am able to do with the trans mounted. would checking working pressure tell me gov condition or if the gov was even functioning? thanks for your reply andrew f

 

when checking the modulating pressure, engine at idle and vacuum hose disconnected. i don't know your trans yet (722.3??) so i can't tell how much it would be.

on working pressure, it should be about between 70-90 bar engine running.

governor pressure is about 0.5 bar, D, and about 1k rpm.

different on every a/t model.

of course a/t is mounted. is it on the floor now? if it is, check for the blockage on kickdown solenoid, t-ring of b1 and b2 (they are all external and opening is not necessary).

b-switch is if there is a B on the shift gate. (p,r, n, 3, 2, b). it is mainly use if you are towing a trailer on up/down hill area. engine braking and can only shift to 2nd gear. shifting time is shorter too.

before, i love doing these transmissions but now i almost didn't do it for a decade. maybe i cannot assemble them blindfolded anymore.

 

so i have my work cut out for me. will post a reply when all or most is figured out. thanks sleepwalker

 

for finish of this thread see "sleepwalker need assistance 300 CD". the rest of this thread is there