What would the max "safe" main line pressure setting vs. mph/rpm be for a stock 4L60E tranny pushing a heavier 3800lb vehicle?
The engine is winding up but doesn't seem to produce much more power after about 4k rpms, was real bad when my Main Line pressures were a lot lower, but I'm afraid to raise them much more for fear of burning up the tranny. They are close to the f-body stock settings now, but were originally about 1/2 that in the stock Silverado truck settings which were too loose for a higher hp motor, LT4.
The stock max setting is around 90 psi for the 94-95 f-body which is much lighter vehicle..

 

i'm running 140 psi at idle in park, and 295 in reverse, 2nd, 1st.

Pressure is good for these trannies.

 

Main Line pressure PSI is a function of TPS% vs. MPH, at idle it should be 0 psi. At WOT, 100% TPS I currently have it set at 90 psi at all speeds. Adjusted by a table in the PCM.
Wondering what the safe values would be for the weight of the vehicle, the heavier the vehicle and the higher the MLP, the more heat is going to be generated in the tranny, but the firmer it will shift.

 

if you want your tranny to hold up you need 275psi when in gear. on my 94z i put a vacume reg. hardend steal pump veins drve ect. anything under 275psi id be afraid to run it to hard. also a good oil cooler is always a plus. my actual pressur is 250 but backs down to 225. i'm pulling it out this week and raising it up or it will die on me.

 

You are talking about lt1 edit. The higher the line pressure the longer the tranny will last. Trust me. I just put my tranny in, and I helped 3 other dudes with 700r4's-4l60's just put their trannies in after losing 3-4 clutch pack, and the 2-4 band.

A shift kit, stronger accumulator springs, billet servo and larger boost valve will increase line pressure.

I don't think the computer can adjust the line pressure for a performance tranny, I think it has to be done manually, via hard parts, but I'm no expert so don't quote me.

 

I'm using TunerCat, but yes, same tables are in LT1 Edit. There are 2 tables for the base Main Line Pressure, one for speeds under 64 mph and one for speeds over 64 mph. The table is TPS% vs speed and then the psi MLP that corresponds to each.
Comparing what was in my original truck to those that were in my wife's stock '95 TA, they are both 0 psi for 0% TPS, then climb up to 90 psi for 100% TPS in the TA and were 58 or so in the truck settings.
With higher hp motor now in the truck, the original settings were just very loose, the motor would wind up to 6500rpms before shifting at about 50% TPS.
I reset the MLPs to be more like the TA's and now it shifts great, but still has some looseness feeling to it.

I don't know if these are actual psi or if the table values are added to what the parts inside the tranny are producing, but it definity does have an effect on how the tranny performs via changing the MLP's in the tables in the PCM.

Good to know that with high hp the psi needs to be higher.
I suppose when the pressures are lower the tranny is looser and has more slippage which causes heat which causes shorter life.

I just wonder how high the PCM can control it before I need to do internal work.
Thanks