Does anyone know what parameter would be letting the TCC lock at 74MPH while at W.O.T?
I've just been doing some W.O.T test runs in my van and noticed that the TCC is locking on once I reach 74MPH and stays locked until I lift off.
It's a 1993 4L60E running an $OD bin, 8625 PCM in a modified G20 van.
There are WOT or Kickdown mode TCC lockup settings in the ECM. From my experience it helps to lock the TCC slightly above peak torque and drag the engine back down to peak torque again. Keeps your engine in its powerband longer and creates more HP to the wheels.Originally Posted by Kitch
Compared to stock, keeping the TCC from locking at WOT was worth a full tenth in the 1/4 mile on a stock longblock L31 with 4.10 gears with a 28" tire trapping at about 4900rpm, 4000lb truck.. The 2-3 upshift would happen, then moments later the TCC would lock. I used to hold the brake light on as that would prevent the TCC from applying.
peace
Hog
I still haven't found what causing it but it is quite annoying, one because it can't be good for the clutch and two when your overtaking another vehicle at W.O.T. the last thing you want is the engine to drop RPM as the TCC engages.
It is the ECM that's locking the TCC at WOT at 74mph in third gear, all 4l60es do this. The 4l80es usually lock in 2nd gear at WOT.
peace
Hog
Maybe its the difference between 4L60E an 80E but mine accelerates quicker and puts more power to the wheels locked.
How good is the clutch in a stock 4L60E converter, I thought they were only supposed to operate under light load conditions?
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