I'm still having problems with my 4l60e. I have no 1st or 4th. I took it to a trans. shop they hooked it up to a tech 2, showed the ecm was telling it to shift, and was shifting, but it's not. I replaced both shift solenoids, filter and fluid twice, checked power to solenoids (ok), took volve body apart cleaned and checked everythng looked ok, Took to autozone code reader showed p0753 shift solenoid a electrical malfuntion, and crank position sensor error, don't remember number, ( maybe different problem). Looked up on internet, seen where voltage variation could trigger this problem. Checked voltage from brake switch (12 volts-not pushed, 11.5 volts - pushed) should reading with brake pushed show zero, could this be my problem. Or what else can i check? Wiring and pcm came from Street Performance. :confused:

you got a wiring problem either inside of trans or outside. tell me what year tranny and ecm is and i could get you a wiring diagram.

With a tech 2, command the solenoid on, you should be able to hear a click, for each solenoid.
With the key on, there should be power to the solenoids.
If there is no power to the solenoid, trans will default to 3rd gear.
Hereitis is correct, wiring problem.
If you can determine what wire at the pcm is the signal wire (ground), you can check the wire for power at the pcm with the key on. That will tell you if the wiring is good. When the pcm turns on the solenoid, there will be no power on the signal wire.
Dale

Trans is suppost to be a 96, bought it out of a junk yard, not sure. Don't have access to the tech 2, at my shop. When at the trans shop with tech 2 hooked up it showed that computor was telling it to shift and that it was shifting, but was'nt. With pan off, test light shows power to solenoids with key on or off, power feed coming from brake light switch like instructions from Street performance says. Not sure if brake switch is working correctly or not. Brake lights work. But voltage does not drop to 0 when pushed. Ground feed is run to the back of the block, block grounded to frame and body, and body grounded to the frame. Should voltage to shift solenoid drop to 0 when brake is pushed. Trans does not just go to third, If i reset code by pulling off battery cable, when i put car in gear code comes right back. Tech 2 also showed a bad rpm reading when testing (probably from the crank sensor problems i have) could this have anything to do with it. Wouldn't think so cause tech2 showed it shifting. Also when cleaning valve body, the pressure manifold switch on the bottom was dirty, and the o-rings on the top side wasn't in real good shape. If this switch is bad could this have anything to do with the problem. Bought new one yesterday will install tomarrow.

Are you using the factory harness and pcm? If so.
The red wire to the shift solenoids will have power with the key on. it is the power for all the solenoids in the trans. You must have the power to the solenoids connected to the non switched side of the brake light switch, I guess that will work. I however would like to see the power supply to the trans off when the key is off.

light green is 1-2 shift solenoid ground
yellow black is 2-3 solenoid ground
white is the 3-2 solenoid ground
These grounds are pcm controlled
if it were a 700r4 the tcc would drop if the brakes were on.
I'm not a trans guy, just know enough to get me in trouble.
dale

I had same problem replaced both solenoids and wire harness it was the TCI tcu. Having said that I would check the wire harness and connector for continuity. I would also disconnect the wire to the brake switch. Your problem is in the 1-2 shift solenoid. Good luck and let us know how you do. What tcu are you using.

I have 1st and 4th now, Don't know what fixed the problem, I cleaned valve body changed fluid and filter again, checked all wiring going to transmission, changed brake switch hookup, changed pressure building switch in transmission, replace crank position sensor, put it all back together and it works now, (shift into overdrive is not very firm, still may have to rebuild, but is working, drove it about 150 miles this weekend. Thanks for everyone's help.