New member here.Was able to fix a slew of issues on this 1990 e4od truck that I just purchased.One thing that I thought might help with the thread regarding resistors for line pressure.In the post,it seems as though many were getting results..some werent.I think the confusion lies in series,and parallel.I tried 2 50 ohm in series for 100 ohms.Shifts were way too hard.Tried 1 50,still too firm.Took the 50,added 2 10 ohm in Parallel with it.Wow.Shifts are defined,no bang.And much faster also.Esp when going into od.Cant belive it is same tranny.Has to be way better for the trans.I also added a spst switch in series around resistors which when closed puts it back to factory line pressure for interstate cruising. Wellused remember..series resistance adds,parallel divides because you added more paths for the electrons to travel..reducing resistance
E4od resistors in..Wow
- Thread starter Wellused
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icanfixall
Official GMM hand model
Welcome to the forum. I'm not really following you as to where you installed these and why. I'm liking the improved firmer shifts and would like to know more about this. Possible pics or wire diagrams sure would help explain more.
Somewhere back in an old post,there was a question about adding 100 ohms resistance in the White/Yellow wire going to the trans from the pcm.From what I can gather,there are 2 opposing solenoids controlling line pressure.When the pcm wants to increase it,it supplies a different voltage ato one of the solenoids allowing it to be "overpowered" so to speak by the opposing solenoid that always gets a 12v reference.He was complaining that his shifts were too hard,but loved the quick shifts and fast o/d engagement(lockup speed is awesome as well) He added a 10 ohm to the 100 already there but said it made it wrse and gave up.I think he added it in series and weakened the solenoid even more..hence violent shifts.So I ran down to radio shack and bought two 50 ohm 10 watt resistors(10 watt can dissapate the heat better than a smaller wattage) and 2 10 ohm,10 watt as well.I installed the 50 ohm and shifts were way too harsh.I installed 1 10 ohm in parallel with the 50(not series) and the change was dramatic.Fast lockup,no shift overlap and nice firm o/d engagement.Still a little harsh on the shift,so added 1 more 10 ohm in parallel and perfection.This e4od shifts as well as any auto I have owned.I will draw up a diagram and post it.It cost less than $6 dollars for this mod,I guarentee it will make trans last longer.I also found that there are 2 different solenoid packs for these trans.1 is 1 ohm,1 is 10 and is used usually in 94 up.So that could change the circuit impedence a little as well.
Also added that switch to "go around" the resistors so to speak so that I am not running a higher line pressure when out on interstate as it is not needed for cruising.There is a diverter valve in the e4 that will dump any excess pressure that could damage the converter,my trans guy says i am no where near that point.
trackspeeder
Stone crusher.
What you have done is tricked the TCM into opening the EPC solenoid more. The EPC solenoid is variable force unlike the others that are on and off. Basically it a budget way of installing a box like Banks or Superior.
