trans pressure &TFMDC

[69camaro5speed]

having problem sliping trans on hi h.p. twin turbo motor the tfm dc i have reading low and trans pressure is still low its like trans has a problem making pressure with 7 % tfmdc pressures are as low as 20 lbs slips trans under hard loads

[69camaro5speed]

never mind put gauge on trans pressure is right just not getting a reading thats right

[69camaro5speed]

looks like trans isnt going into 4th gear anyone know if theres a setting that keeps trans out of 4th gear under wot one of the logs i have said it was in 4th but with the rpms its at theres no way

[ScarabEpic22]

I dont have any experience tuning anything but LL8 engines (4.2L I6 trucks), so I cant say for sure, but I know for my engine/trans there has to be both a rpm and speed parameter before it will shift. I imagine if you dont want it going into 4th, just set the speed part to like 256 (max out the table because your car will never hit that, get my drift?).

[69camaro5speed]

i want it to go into 4 th thats my problem its not happening or its sliping so bad when it does its hard to tell it goes from 60 to 115 in 3.3 secs when it doesnt spin to bad its a 582 with twin turbos in a 2005 suburbin probly 7000 lbs i am thinking that overdrives not strong enof to handle it like to know if anyone has ever used overdrive with any thing with lot of power

[joecar]

Sounds like you got plenty of torque/power...
Is your 4L60E built up for that kind of torque...?
From your other post, you're not getting enough line pressure.

Note: TFMPRS ranges 0-96 psi and indirectly controls line pressure from 120-230 psi.

showthread.php?t=3994 (http://forum.efilive.com/showthread.php?t=3994)

[SSpdDmon]

I bet you're slipping the hell out of those clutch packs with the power you're making and the weight your pushing.

[69camaro5speed]

this project started over a year ago its a 582 inch big block was going into a 94 suburbin. then the guys wife totals a 2005 he gets it back for 2000 dallors and says i like to use this one.me thinking all it takes is time and money guy says ok 80k later me and the chassis builder are test driving it. thats the short of a long story. old school motor with a mix of dfi and efi live ( would have loved to have used all efi live but old style block i had know way to make it work)things have gotten better got it going into over drive from 70 to 140 in a hurry looks like 150s max for the 4.11 gears and rev limiter at 5800. the trans is a 4l85 and converter built from suncoast converts seems to be holdings up ok so far when it comes on boost goes 4100 or better though.my pressure with a gauge is around 180 or better i didnt know how the tfmdc and the pressure reading where realted to whats going on.my tach signal isnt working 100% right and i have bus and data lines that i havent a clue where they go using a 2006 express van 6.0 operation system so i can steal tps from the gen 7 dfi no fly bye wire with that operating system. every thing works ok but the converter kicks in and out i did the misfire temp to 1 deg still does it. ok enof for the night ass draging to bed thanks for every ones help keeps inching me forward on a bastard but rocket ships ride thanks

[joecar]

As TFMDC (%) goes down, TFMPRS (psi) goes up (this is the case for the 4L6xE and the 4L8xE)...

i.e. if the PCS solenoid fails (i.e. duty cycle goes to zero), TFMPRS pressure goes to max which indirectly sends line pressure to max.

Either way, can your 4L85E hold twin-turbo-big-motor-torque...?

At WOT, I would still expect line pressure to reach 230+ psi, and if it doesn't, then you will have internal slipping as SSpdDmon said.

You must make sure that the VSS, TPS, RPM, MAP/MAF signals are good, or else your trans will slip alot and die and/or shift wrong.

[69camaro5speed]

seems to be ok so far its never been hooked hard spins to eazy tires are off road type i cant load the motor under 4100 with full boost ( converter flashes that high ) hasnt broken yet. i set do935 down so wouldnt kick out of overdrive it pulled hard to 140 then had to let off was coming up on a car quickly i have a log of that if you like to see it one in efilive and one from the gen 7 i have vss,tps,rpm not 100% brakes up at uper rpms probly my hole problem,map,no maf have it defalted to sd. with out wiring diagrams i can look at for the 2006 express van operating system i dont know how to try hook up the pins 14 15 on blue connector uart serial data (jl4) and 58 class 2 serial data on the green connector theres no. 5 delivered torque signal ( jl4) woundering if they need hooked up

[joecar]

having problem sliping trans on hi h.p. twin turbo motor the tfm dc i have reading low and trans pressure is still low its like trans has a problem making pressure with 7 % tfmdc pressures are as low as 20 lbs slips trans under hard loads
As TFMDC (%) goes down, TFMPRS (psi) goes up (this is the case for the 4L6xE and the 4L8xE)...If your TFMDC is reading low (close to 0%), then trans pressure (you're measuring from tap on side of case) should go high (above 200 psi)...
if it doesn't, then either your pump is leaking/failing, or the pressure regulator valve is stuck, or the PCS/TFM solenoid is leaking, or pressure is leaking from someplace.

In the diagram (4L80E), check out how the PCS solenoid feeds the pressure regulator thru the boost valve (yellow and dark-yellow)...
If there's a leak, or a stuck valve, or failed component, or low pressure from the pump, then line pressure will be low...
sorry diagram is so large, it is odd-shaped...

http://img169.imageshack.us/img169/7449/4l80ecommonro3.png

[ScarabEpic22]

Hey, do you happen to have one for a 4L60E trans, looks like it might be interesting info. (Or is the 4L80E close enough?)

[joecar]

4L60E is very similar, a slightly different...

Sorry for the big size, that gave the best looking text.

http://img292.imageshack.us/img292/7862/4l60ecommonah3.png

[ScarabEpic22]

Thanks for the diag man.