Hi guys I would love to see a tune for a 4l80e trans for my Pontiac 455 single turbo car , I am using us shift controller and have loaded the 6,000 rpm tune , the issues that I am having are you have to come to a complete stop for it to go into first gear so at 5 mph it stays in second also 2nd to 3rd gear is super soft … if any body has a tune that I can download for a turbo car , I would appreciate any help tuning . Thanks

 

Send them an email or look at a different "stock" tune looks like to see how the downshifts are set up.. The Gents at US Shift usually respond to me within a day..

ks

 

Thanks bud

 

typically , most transmissions dont drop to first until a complete stop. They will drop to first if you are appling enough load inside a set mph window though.

 

Current supplied to the Pressure control solenoid controls the internal transmission pressure.
The current range is 0.05amps to 1.005amps.
The lower the current, the more transmission pressure is commanded.

The actual pressure must be measured at the transmission inspection port (or whatever its called) there is a 1/8" Npt plug on the top of bellhousing area where you tap into using a 0-300psi transmission pressure gauge.

WOT with typical 4l80e should be 195 to 205psi of pressure, for mild 500-800 horsepower builds around 3600lbs vehicle.
This could take anywhere from 0amps to 150mA to achieve if the trans is stock, and if the pump is aged it might not even reach that high.
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The more difficult to turn and heavy a drivetrain is, for example heavy wheels, numerically low gear ratios, heavy vehicle, the more pressure the trans will need when shifting and holding torque.
It might help to think of the EPC control as a sort of TV cable if you have experience with the old cable style of transmission pressure control. As you pul out the cable, pressure increases, similarly as current drops to the EPC, pressure increases. The great thing about electronic control however is that you can non-linearly adjust the pressure for situations, for example if you want a tire chirp at part throttle you can command more pressure than a cable would naturally provide.