99 Chevy Silverado 1500

sounds like a torque converter control solenoid. it is an electrical plug on the trans. unplug it and see if it "fixes" if it does, you can drive it unplugged, but your mileage will suffer.

Thanks that's what I thought to changed the solenoid still locking up thinking it has something to do with the alarm now can have key on and plug up battery and security light blinking but cranks and then dies in reverse or drive with key off and out plug up battery and alarm sounds but no security light on and of course I lost the alarm clicker if you can think of anything at all would appreciate it

Weirdest thing I have ever heard. Try calling a dealer service department. Sometimes on security system issues they can help.