1999 C1500 Transmission Issues

I have searched the fourm and did not find enough detail to feel confident that I know what my issue is. I have a 1999 C1500 with 140K miles, no codes. When I begin to accelerate it feels as though I am intermittently applying the brakes, sort of jerky slipping feeling. There was also a ticking around the front of the transmission. My wife is the primary driver and I'm afraid to let her continue to drive until I can fully understand what the problem is. Any ideas? I apologize if this has been discussed and I overlooked. Thank you.