I have searched all over the web and found a lot of conflicting information on this issue. I have a 1991 GMC 3500HD with a 5.7 and 4l80e and 5.13 rear. It has a jasper rebuilt transmission since before i got it. It shifts hard from 1-2, but shifts smooth in all other gears. It always has a Dtc 73 when i check for codes.
The force motor wires ohm at 4 ohms at the pcm connector. No short to ground on either wire. Transmission internal harness was leaking at the plug so i pulled the pan and changed it as well as the filter and force motor. It already has the updated harness. It had the black Holley force motor and the kit that i bought also came with the Holley force motor.
The kit i bought claimed to be for a 91-96 4l80e. I read a pdf for this tranny that said to replace the silver bosch force motor with the black holley one. My pcm is sending 6 volts at 225hz and .7 amps at idle in park. It drops to .6 amps in first gear, but volts and hz drop to zero in any other gear while amperage rises to .9 shortly before the ecm cuts power to the force motor altogether and sets the dtc.
I have even disconnected the alternator to eleminate any chance of electrical harmonics causing this, but still have the same problem.
So at this point, im wondering if i need to get the bosch force motor or does this seem like a pcm issue?
I have attached the pdf that states to use the holley epc solenoid if the trans has the silver "german" epc solenoid.
The force motor wires ohm at 4 ohms at the pcm connector. No short to ground on either wire. Transmission internal harness was leaking at the plug so i pulled the pan and changed it as well as the filter and force motor. It already has the updated harness. It had the black Holley force motor and the kit that i bought also came with the Holley force motor.
The kit i bought claimed to be for a 91-96 4l80e. I read a pdf for this tranny that said to replace the silver bosch force motor with the black holley one. My pcm is sending 6 volts at 225hz and .7 amps at idle in park. It drops to .6 amps in first gear, but volts and hz drop to zero in any other gear while amperage rises to .9 shortly before the ecm cuts power to the force motor altogether and sets the dtc.
I have even disconnected the alternator to eleminate any chance of electrical harmonics causing this, but still have the same problem.
So at this point, im wondering if i need to get the bosch force motor or does this seem like a pcm issue?
I have attached the pdf that states to use the holley epc solenoid if the trans has the silver "german" epc solenoid.