I keep reading online and in videos I see gauges on 4l80e's and they read 200-300psi sometimes.
My HPtuners says max pressure is 90psi.
Another strange thing I see is:
My closed throttle tables show 60psi yet my 1st to 2nd gear shift shows 12-20psi for 200~ft*lbs of torque.
How can the trans need twice the pressure in neutral than when it's shifting from 1st to 2nd?
You are not reading actual pressure. There is no feedback sensor on a 4L80 trans.What you see most likely is speculated EPC pressure. So, if you were able to measure EPC pressure with a gauge it should match. 90psi EPC pressure should give you 300psi in reverse.
The underlying Force Motor Current table is the direct value used at an ascribed pressure, so you have more adjustment than what is in the pressure table alone.Originally Posted by staytuned
So whats an EPC?
Is it possible to simply reduce pressure until I notice the trans is slipping a bit and then add back a little bit of pressure?
I'm afraid to use too much pressure.
So I Swapped the trans pump with a rebuilt unit but I still hear a very notable whine coming from the 4l80e, the pump I guess just whines.
It did get rid of the pump "death rattle" it had in neutral sounded like clacking clattering before when full warm.
So now I am hearing this kind of electronic high pitched noise, buzzing barely audible and it only happens sometimes. I wonder if this is the electronic pressure control device making that noise? It sounds "normal" like I am not concerned about it but still curious what it means. It comes and goes, sometimes when I go to drive I hear it. and sometimes in neutral.
I just wonder how much pressure I should be using at neutral. The factory table says like 50% which to me seems like way too much since 1st gear is like 28%. Im afraid to lower it though because of the chance that needs that pressure.
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