01' Silverado Surging problem

I have a 01' Silverado Z-71 with a 5.3 and 147,000 miles. When I'm driving down the road it seems that the tranny surges at about 45-55 mph. The rpm drops like 100 to 200 rpm and its annoying as hell. I replaced the TC and nothing so I changed the TC solonoid and nothing. Any help would be a great.

I have the same problem with my 00 silverado. This has been going on for a year now. I was told by a transmission specialist that it was a valve in the body in the transmission.It is worn and keeps kicking in and out. He said it will just keep doing it.
I think at the time it would cost about 300 bucks to fix. I never got it fixed because of not having a job. It still runs good but it is annoying. It doesn't do it when it is cold in the morning, but will start about 10 miles into the trip. There is a kit that you put into the body to repair it. A rebuilt body from GM will have it already installed.

I think that is your problem. it sounds exactly the same as mine.

I have a 01' Silverado Z-71 with a 5.3 and 147,000 miles. When I'm driving down the road it seems that the tranny surges at about 45-55 mph. The rpm drops like 100 to 200 rpm and its annoying as hell. I replaced the TC and nothing so I changed the TC solonoid and nothing. Any help would be a great.

it won't be long and you'll start to loose gears...what type fluid have you have been using in this ? what is your fluid change intervals ..?

your issue sounds like the tc is not locking up correctly...if it is intermittent when it acts up gently hit the brake pedal see if it stops...

tc on my vehicle locks up at 40-45MPH...light throttle...