theres a little rubber boot that sits where your steering column goes through your firewall that can make this sorta noise, apparently pretty common. Just put some grease in it, and see if that fixes the problem
I'll claim that rubber boot fix, it will sound like the steering rack, just follow the steering colum up from the rack connection push the boot up and give it a small squirt of some teflon spray, lasts for years.
It's just the outer weather seal rubber grabbing on the dry shaft, seen guys change racks and spend hundreds only to find the same noise still there.
So many seemed to think it was a normal commodore trait, it's not.
Simple enuf to get someone or yourself under the front to check where it's noise is coming from, racks do stuff up often on commos but the above fix has saved many the cost of a new rack when nothing is wrong with the one being replaced..
The above fix will be heard even if the wheels are off the ground or the rack is remo0ved, at worst bout $100 for another s/h one or $150 for a reco unit, just make sure it's got good tie rods on a s/h one and that it don't come from a front end smash.
Some will fit in without an alignment, but no two will be setup the same, at worst loosen the tie rod and turn em unitil the wheels are about 1/8" toe in.
I dont think there's anything wrong with the steering column, I remember the last time the car went to the suspension repairer the guy said he just lubricated something and it worked fine. I'm thinking this is what he did. I'm just not sure where exactly the boot is or where the best place is to access it?