power steering conundrum; why must it groan?!?!?!

I have a 97 Taco 4x4 with the 2.7

I've had it for over 2 years and have had the same problem since I bought it.

When the truck gets up to temp, the power steering pump makes a very noticeable and scary groaning whenever the wheel is turned especially when the truck is sitting still.

the particularly weird part is that if the ambient temp is below about 75 F, the pump will never make a sound even after the truck has been running for an hour or more and is up to temp. Once the ambient temps get into the upper 80s and 90s especially, the pump will carry on until it is allowed to cool down.

I have replaced the pump twice, checked for leaks EVERYWHERE, and replaced the rubber hoses just to say I did so and none of it seems to make a difference.

Since it only acts up on hot days, I was thinking about grabbing one of those power steering cooling kits like this:

http://shop.advanceautoparts.com/p/...g-oil-cooler-241009/19230069-P?zoneAssigned=1

Any thoughts?

 

When you replaced the pump, did you also replace the reservoir (with the filter screen inside) ? When mine made a growling noise occasionally, I cleaned the screen, and noise went away.

 

Got enough ATF fluid in it? Mine groaned when it was low.

 

Yep, screen in reservoir sounds like it could be culprit as tan4x4 states.

 

Mine has never made a sound unless it was low.

When low it makes a nasty howling noise.

 

when I replaced the pump I did not replace the screen but I did thoroughly clean it out. there wasn't much crap in the screen anyway.

the fluid is definitely not low. It was actually a little over full and I have since taken some fluid out but the groan still continues.

doesnt the fact that it only groans when its hot enough interest anybody or indicate something particular?