97 Astro Whining and Grinding when turning

[RandyW01]

My 97 Astro AWD, just started making a whine when warm and turning left or right. Now it is also making a loud grinding noise when turning left or right. I checked the Power Steering fluid it was low. I put 2 bottles in to fill it up.

Any idea what is causing this?

[Kings-x59]

I'd venture a guess that since it took two bottles of power steering fluid to refill the resevoir, that the noise is coming from the power steering pump. (meaning it's probably shot) If the power steering pump runs dry of hydraulic fluid it pretty much grinds its inards' to dust.

[RandyW01]

Originally Posted by Kings-x59

I'd venture a guess that since it took two bottles of power steering fluid to refill the resevoir, that the noise is coming from the power steering pump. (meaning it's probably shot) If the power steering pump runs dry of hydraulic fluid it pretty much grinds its inards' to dust.

That's what I was thinking, but wanted other opinions first. Thanks for your help.

[drew300]

And don't forget, your power-assisted brakes use the steering pump too.Get it looked after.

[RandyW01]

I had a guy that was going to change the Power Steering Pump for me. He test drove it and decided that the problem was a rotor and brake pads. The power steering was working as there was no difficulty in turning the steering wheel.

He changed the rotor and brake pads. We test drove it and the more we drove it the more it appeared the noise was going away. Well I went to drive it home and made a stop on the way. When I went to back up, something was making the vehicle stop before I could get all the way out of the drive way.

All the way home it was making different noises. On tight turns it would making noises and feel as if something was causing something to hang up and the wheels seemed not to want to turn.

After it cooled off, I took off the tire where the rotor had been changed. Everything looked fine there. I put the van in neutral and attempted to turn the rotor by hand. It would not turn smoothly. It kept "catching" on something. Then when it was back in park, and I was putting lug nuts back on, it would turn in the same manner. It turned but kept "catching" on something.

1. Shouldn't the rotor turn smoothly in neutral?

2. Shouldn't the tire not turn at all in Park?

I am starting to think it is the cv joint or the front differential. Any ideas??? I did climb in under and look at the differential. The power steering pump is definitely leaking onto the differential.

Any ideas or comments would be greatly appreciated.

[drew300]

Sounds like you may have a few problems, not one.
Odd that the noise "was going away" the more you drove it, and that you couldn't back up.
I'd check for debris in the pump oil, to get a clue from that. If the oils clean, and still topped up, a small leak might be fixed with some stop-leak product. Don't waste your time if it's a big leak or dirty.
A disc brake aways drags a bit. Once "broken free" by hand, it should be pretty easy to rotate by 1 hand. A warped rotor will show itself with a higher drag spot or 2. (that's a brake only, not one with an axle on it)
I'm not familiar with the type of AWD used on an Astro, but shot CV joints could cause a lot of funny noises, getting worse with steering inputs, as well as causing "catches" as the wheel rotates.
I expect you could do a rudimentary check just seeing how much play the joints have. I would expect none at the joints. I'd check for different amounts of play as the wheel is rotated.
In park, the output of the tranny is locked, not the drive train. One tyre off the ground should turn a bit, until all the play is taken up in the drive train. (again, I'm not familiar with what GM is using, but I don't think there's an automatic-unlocking hub)
BTW: If there is no locking center diff in the van, a broken CV axle will leave you stranded where it lets go.
Hope this helps

[chcknugget]

I would change the fluid in your transfer case. It will probably take away the grinding when you turn, and it costs less than $10 to do yourself.