1998 Camaro 4L60E slips in only in 1st
 

I have a 1998 Camaro with a 4L60E and the limted slip differential with 178000 miles on the odometer. At first it didn't want to shift up out of 1st gear from a complete stop and now it has started slip in 1st as well. If I let out of the gas for a second it shifts up and then it shifts fine. Also in reverse the rear end makes a popping sound for about 5 seconds then it goes away. None of the warning lights have come on either. The only work that the previous owner had done to the car was a new differential about 10 years ago. Any help, ideas, or suggestions would be appreciated, thanks!

Sound like your transmission is having pressure issues. It could be the pump but most likely is just a weak pump combind with worn seals and clutchs. In short your trans is wearing out. There is a a couple of things in the trans that can cause a clicking noise in reverse. It much more likely that noise is coming from the trans and the noise is traveling thru the torque arm or drive shaft and into the rear. Rears are easy to inspect for damage. Your transmission is going to need a rebuild.