98 blazer transmission problem

When i am crusing @ 55 mph (+-2 mph) the transmission will try to down shift many many times which results in the RPM gauge jumping (200 to 500 rpms). This will constantly happen until I reach 60 mph or 40 mph.
I checked my TP sensor = OK. I replaced the TP sensor just incase (problem still persists) No lights, No Codes. Fluid has been recently changed.

Anyone have any suggestions.

Are you sure it is downshifting, or is the TCC un-locking and then re-engaging.?

Are you sure it is downshifting, or is the TCC un-locking and then re-engaging.?
I am fairly sure that is is down shifting. I am not sure what it feels like when the TCC unlocks then re-engages

it is the TCC unlocking and reengaging.

This is usually caused by a driver that cannot keep constant pressure on the pedal and is constantly accelerating and letting off the gas.

Try the cruise control at that speed. If the problem goes away, you know what the problem is. ;)

To see if its your TCC, get the truck up to cruising speed (this is easier if you get on the highway, you'll notice the difference right away if its TCC). Get it up to speed, keep one foot on the gas pedal, and with your other foot lightly push the brake pedal a little. If you have a tach on the truck, you'll notice a difference in RPM's, also you'll feel it it too. This is the easiest way to see if your TCC is causing your problem.

When i am crusing @ 55 mph (+-2 mph) the transmission will try to down shift many many times which results in the RPM gauge jumping (200 to 500 rpms). This will constantly happen until I reach 60 mph or 40 mph.
I checked my TP sensor = OK. I replaced the TP sensor just incase (problem still persists) No lights, No Codes. Fluid has been recently changed.

Anyone have any suggestions.

I had the same problem on my 97 after I changed the fluid and filter and valve body on mine. A transmission flush and detergent rinse seems to have solved my problem.