05 Trailblazer whining sound

I have a 2005 2wd trailblazer with about 100k miles. When the car first starts for the day it has a loud whining sound for about 30 seconds. Sounds like it is coming from transmission. After the 30 seconds all is good. It has been getting progressively worse. Almost sounds like a jet engine. The sound will sputter and few times and stop. Please help. Its not the clutch fan or belts. It definetly from the back side of the motor.

Tough to tell from here, no? Someone has to listen to this onsite for any meaningful advice. A partially clogged fuel filter could do this or as you say could be in the trns.

Use a mechanic's stethescope to pinpoint?

I overhauled the tranny and it was in the torque converter or the gear clusters. oh well its fixed $1500 later

I currently have the same thing, same car, less miles. Its the secondary air injection pump. Valve is also bad. Comes with a check engine idot light. Pump is located directy under drivers sead next to the frame rail of the car. Part of emission contol system.