It engages the band witch makes your tranny shift into gear.
There are several reason why this could be happening. There could be a linkage broke, a bad pump or just a bad transmission in general. Most likely the pump is bad or the transmission is bad.
Start looking for a tranny
Because it engages/disengages the rotating power of the engine from the transmission.
bounce off the rev limiter let clutch out till it engages then push clutch in and repeat and repeat and repeat
Sounds like transmission needs to be overhauled
I think you're talking about an impact wrench. Or it could just be a drill with a socket adapter, but most drills don't have the torque required to do this without someone getting it started first with a lug wrench or something. An impact wrench is basically a drill with a sort of transmission device. The drill shaft rotates freely intially to build up momentum and then the transmission engages to deliver a lot of torque all at once. Impact wrenches tend to make a characteristic "rattling" sound as the transmission engages and disengages.
P0742 means that your torque converter clutch circuit (TCC) is or was stuck on. In other words, the lock-up torque converter was engaged when it wasn't supposed to be. The torque converter uses transmission fluid at lower speeds to transfer motion from the part of the transmission connected to the engine to the parts of the transmission connected to the drive shafts. This is what allows you to stop your car at a stop light without having the car die. When the torque converter engages ("locks-up"), a clutch engages, creating a mechanical connection that makes both parts move together more efficiently at higher speeds (above ~49 mph). This allows you to get better gas mileage on the highway, since the fluid coupling is not very efficient at those speeds. If your TCC fails to disengage or engages when it is not supposed to, it will set this code. You may notice the car chuggling at lower speeds or dying at stops. This problem may be caused by a failing TCC solenoid in the transmission. The 4T65E transmission in Impalas is completely electronically controlled. However, it may also be caused by other transmission problems.
If the rest of the Transmission continues to function, then result is that the engine RPM's will be higher when cruising than is normal. Overdrive reduces the RPM's at the speed where it engages.
The transmission shifts through gears as your engine rpm increases and your transfer case engages and disengages your jeep in and out of 4 wheel drive. Your transfer case also has gears for 4x4 high or low.
Toward the rear of the engine compartment - near the firewall - on the lower part of the engine. The starter engages the flywheel, which lies at the rear of the crankcase and ahead of the gearbox/transmission.
Front or Rear Wheel Drive?? If Front Wheel Drive, look on the front (facing the radiator/a.c. cooler assembly) and Starter should be on bottom at Transmission coupling which when facing Engine from front will be on your Right. The Starter engages the Flywheel on the Transmission. If Rear Wheel Drive, look on Passenger Side of Engine bottom at Transmission Coupling. There may or not be a Starter Dust Cover. Bolts will most likely be Metric.