The low cost of a part often has nothing to do with how much work or what a PITA the work is to do. Some will do these jobs whilst eating breakfast and find all jolly spiffing, you might want the learning experience. But then there's also the risk of damage and finding associated work from starting the job, it might not be the case for this job, but it might, more joy for some and perhaps yourself.
Whilst the diagnosis is a high probable it's never certain given it's just from your typed description and can't for certain say why it is happening, the cause, and if there have been other effects meaning more work and parts required to complete the job. Given your following post, which may or may not be related as you seem to have other issues with the car, the work could be mounting.
Photos and videos often help as obviously more can be seen (especially if you video in landscape where appropriate and not just portrait) plus audio of noises and operation, can help.
If you don't desperately need the car to use you could take things apart for a good look or if there's access you could use a cheap borescope on your phone to have a look-see inside without taking things apart. Or once things are apart you can decide whether to press on or put things back together again and hope for the best.
You also need to prioritise the jobs that need doing, unfortunately the cheapest, easiest or one you most want to do isn't alway the job you need to do first.
I have no idea about your car but if you are short of money you cannot be sentimental you must know when to draw the line with an old car and not throw good money after bad, I would have the T-shirt for this behaviour but I couldn't and can't afford it.
Good luck, whatever you decide or do.