I have a 1997 ford ranger 2.3l manual. It came without power steering so that can't be it. It makes a high pitched whistling sound at higher rpms and it goes away when I let off the gas. It does not have a turbo and I don't think it's the tranny. It does it in all gears sometimes especially when really cold. And also it does not subside when driving down the highway. I replaced the vacuum solenoid and that fixed the rough idle but the whistle continues to get worse...

Try a good dousing of carb cleaner through the intake system.spray into air filter intake pipe at high revs,engine will die,allow to recover revs and go again,it worked on my lr d3.

any part driven by the drive belt can do this

Sounds like you either low on power steering fluid or you need a new power steering belt. Otherwise, your power steering pump might be bad. Are you in the US? You can probably take it to an AutoZone or an Advance Auto and one of their guys would be able to give you a confirming diagnosis. Check the first two first.

this problem is evident in vehicles that have a strut suspension
at the top of the strut there is a plate that is the top plate for the suspension coil spring
above that plate in the rubber bush is a bearing
if that bearing has failed then the plate will not turn and when you turn the steering wheel the power steering is in effect winding up that coil spring
that makes low speed turning very heavy on the power steering system especially at low rpms
have the front suspension checked for that bearing failure ( both sides ) by an accredited suspension specialist shop
standing stationary and turning the wheel you may even hear a creaking or groaning noise as the spring is flexing on the strut
if you do not have a strut suspension , take it to a power steering specialist shop for a proper diagnosis

the grinding sound and the high pitch sound may not be related.
the grinding in the brakes means it is time to replace the brake pads / shoes and either replace or repair the discs and drums.

the high pitch noise that you are hearing while turning is more likely caused by a worn belt, low power steering fluid, or a faulty power steering pump.

Although it could be indicating something more serious like hub bearings going out, your best bet is to take it to a front end shop that offers free estimates and have them diagnose it in person.

hope this helps.

no this is not the transmission, based on my experience it is most likely the power steering pump, if is the single most common source of this type of noise in any Ford

this sounds odd but mine did this when i replaced the wipers. it seems the design of the wiper frame was making a whistle at higher speeds. the freestar wipers are exposed on the window cowl and not hidden so they endure the winds at high speed. it is worth a shot.

Mine has a high pitched whistle at high rpms and I can't figure it out. But mines def not the tranny. I'm thinking it's a vacuum line somewhere. It's a 97 2.3l manual. The colder it is the louder...

Power steering pump cover is loose or missing

The problem could be anything from a power steering hose has leaked out all the power steering fluid or the steering rack could be leaking fluid. Has the car made any strange noises when turning the steering wheel? A car that is loosing power steering fluid will at some point lose so much fluid as to make the power steering pump cavitate (starve for fluid) and the pump will make a high pitched noise when it has too little fluid in it. I can't remember if the 1996 ranger had only one belt on the engine or if the power steering has it own seperate belt. The belt being gone would prevent the power steering from working but if you only have one belt the car would also overheat.