Power steering pump failing?

My '02 Denali began experiencing some power steering vibration recently when turning the wheel in either direction. The sensation is similar to a low power steering fluid condition. After adding some fluid to ensure the reservoir was full, the problem still exits. The wheel is also slightly harder to turn. Is this a sign that the power steering pump is failing, an issue with the pump shaft or something else? The truck has 46k miles and I had the power steering gear box replaced under warranty about 1-1/2 years ago.

Hi,
could there be a leak where air comes in?
Is there foam in the fluid?
What does the dealer say?
Take care, Eggert :bananasmi

I haven't detected any leaks. I re-checked the fluid level yesterday and it hasn't dropped after adding some last weekend. The reservoir cap makes a suction noise when first removing so it appears to be sealing correctly and there is no foam evident. I haven't called the dealer yet because I suspect they will want me to bring it in to diagnose.

My '02 Denali began experiencing some power steering vibration recently when turning the wheel in either direction. The sensation is similar to a low power steering fluid condition. After adding some fluid to ensure the reservoir was full, the problem still exits. The wheel is also slightly harder to turn. Is this a sign that the power steering pump is failing, an issue with the pump shaft or something else? The truck has 46k miles and I had the power steering gear box replaced under warranty about 1-1/2 years ago.
There is a steering position module that might be wonky

This module, I bought mine from HELP part #31025

About an hour to replace.

Slide seat fully back

Disconnect neg ground for at least half an hour to Disable air bags.

Remove 15mm nut to separate steering shaft just before it goes through firewall under the dash.

Push shaft off towards, (through the) fire wall.

The device is in a grey housing concentric to the shaft,

Carefully work back the three plastic clips and the disk will come free

Carefully remove locker (a plastic insert) and unclip junction to device lead.

Slide off disk

The plug will slide out if you tease it through carefully.

Clean shaft with electronic cleaner

Install new sensor the brass goes towards the steering wheel.

There is a slot in the top of the gray housing to locate the wires

Tease the coupling back into position reattach and insert lock

Click the sensor in place

Reinstall shaft and bolt.