Transmission questions

[adt123nvegas]

ok, 1992 bronco, 351, automatic. I am almost positive its an E40D transmission (20 bolt pan). The problem I am having is that it constantly searches for a gear, or doesnt seem to stay in the correct gear. It pulls ok, but from a take off it will shift through all the gears quickly, then jump back one or two gears and stay there t a higher than normal rpm (2000 to 2500 at maybe 35 mph). I can play with the throttle and it will shift up at maybe 3000 rpm, then as soon as I slow down it jumps right back. Turning off the over drive only takes out the o/d gear, but the transmission does the same thing. It acts like a modulator valve on other transmission problems I have had in the past. I go to the parts store and they have 3 different modulator valves for it. A green stripe, black stripe, and purple stripe. Whats the difference in these? I tried to find it on my transmission and I cant find it anywhere. Referenced Chiltons and they only talk about a modulator for a C-6. Does an E40D have a modulator valve? If so, where is it at and how do I tell what type is supposed to be on it?

Thanks for all your help.

ADT

 

[BLADE262US]

The E4OD says it all in its name Electronic 4 Speed Overdrive . That transmission doesnt have a modulator valve it is totally controlled electronically by the EECIV computer . What your experiencing is probably going to be expensive to fix but heres a couple things you can try . There are 2 electrical connectors on the drivers side of the tranny . One black one grey carefully unplug them and look for any corrosion if there is or if there isnt clean them good and put diealectric grease on them and plug them back in . Try to drive it again see how it acts . If still not right on drivers side fender well youll see where that harness from the tranny comes up there and plugs into anlther harness which then goes to the EEC plug unplug each of these connections and clean them the same way grease and plug back in then drive again if no luck then heres the expensive parts . It shifts off vehicle speed and load ( hmmmm also check your TPS for adjustment ) so it gets its speed reading from a speed sensor in the tranny not sure how to check that other than change it out . If the fluid looks good it will more than likely be an electrical connection problem . /emoticons/[email protected] 2x" width="20" height="20" />