I have a 1981 380 SLC with 110 000 miles. The transmission filter and gasket and fluid was changed about 10 000 miles ago by the previous owner (I can`t contact him for questions unfortunately). The transmission shifts into reverse, 1st, 2nd, and 3rd fine, but in 3rd gear at about 2000 RPM the transmission will slip out of gear sometimes. I have to let off on the accelerator to bring the revs down. The slipping out of gear seems to be worse when the car is cold but still persists even when it warms up.
Is this most likely a band, modulator valve, or kick down cable problem?

Thanks!!!
Dr. J

 

Do a search on 'flare'...
The most common flare occurs in the 3-4 shift, with some occurrences in the 2-3 shift. The flaring condition exists due to a lack of shift overlap caused by slow filling of a clutch pack either through greater fluid volume needs of loose clutch packs or fluid losses through pack seal leaks . Cars with this condition can have their relative shift pressure improved by getting the high shifts sooner so they will be made with greater throttle, giving lower vacuum and greater pressure. If the shifts are made as the throttle is backed off, then the pressure drop in the modulator is very high.
Try adjusting the pressure modulator first.one turn increases the pressure by 0.3 bar.