4l60 no convertor lockup once warm
02-09-2007, 03:02 PM
#1
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4l60 no convertor lockup once warm Heres the story. I have a built 4l60 that has no problems whatsoever, except for one minor thing. The convertor never locks up once the transmission is warm. 
This has been this way for a couple years now, and its time to get to the bottom of it. It is not the convertor, it has done it with 3 different units. Right now I have a 2200 stall on it with my Vigilante 3800 sitting on the shelf until the problem is fixed. Valve body is new. All solenoids are new. Wiring harness in transmission is new. New transgo shift kit. O ring on input shaft is new. Fluid is new. Again, convertor is new. This is what happens. Start the car in the morning, convertor locks up like normal. Drive the car around for a few miles, heating up the fluid, and this is when the problem starts to occur. I can drive the car with it functioning properly all day long in any weather, and it will lock up as usual until I come to a complete stop, then it will never lock again until it sits overnight and I start the whole process over in the morning. The output is going on for the solenoid to fire to lock up, but it does not lock. Once warm, after coming to one complete stop, using the TechII, I force the output, solenoid comes on, no lockup. If I do this when cold before stopping, I can lock and unlock it all day and it works, again, until I stop. Any ideas? Any possible causes? Poor fluid flow? Anything, I want to put my 3800 back in, but it heats up the fluid so bad that it buries my temp guage after about 10 miles. Thanks, Nick
This has been this way for a couple years now, and its time to get to the bottom of it. It is not the convertor, it has done it with 3 different units. Right now I have a 2200 stall on it with my Vigilante 3800 sitting on the shelf until the problem is fixed. Valve body is new. All solenoids are new. Wiring harness in transmission is new. New transgo shift kit. O ring on input shaft is new. Fluid is new. Again, convertor is new. This is what happens. Start the car in the morning, convertor locks up like normal. Drive the car around for a few miles, heating up the fluid, and this is when the problem starts to occur. I can drive the car with it functioning properly all day long in any weather, and it will lock up as usual until I come to a complete stop, then it will never lock again until it sits overnight and I start the whole process over in the morning. The output is going on for the solenoid to fire to lock up, but it does not lock. Once warm, after coming to one complete stop, using the TechII, I force the output, solenoid comes on, no lockup. If I do this when cold before stopping, I can lock and unlock it all day and it works, again, until I stop. Any ideas? Any possible causes? Poor fluid flow? Anything, I want to put my 3800 back in, but it heats up the fluid so bad that it buries my temp guage after about 10 miles. Thanks, Nick 
02-09-2007, 04:42 PM
#2
My best guess is the lockup valve in the pump is sticking when hot I have seen that before on several units will only mess up when hot , , remove the valve clean bore, use emery cloth very fine to polish valve , reinstall valve and stoke many times till feels free,
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