power steering problem? or AWD binding? - Toyota Nation Forum : Toyota Car and Truck Forums

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post #1 of 3 Old 03-18-2010, 04:12 PM Thread Starter
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power steering problem? or AWD binding?

i'm trying to sort whether my power steering pump is giving up, and whether to replace it, and it dawned on me that the noise/symptom i am experienceing could be an AWD binding.

at very slow speeds, like parking lot speed, at nearly full steering lock,
i get a savage deep groaning noise. there is no radical vibration associated with it, but you can "feel" the groan/grind in the steering wheel.

upon quick inspection, the drive belt for the power steering pump feels to be in decent condition, and tight enough.
the power steering fluid reservoir is full, possibly a bit over-full.

i am going to fasten a microphone under the hood in front, and then zip-tied directly to the PS pump, and then compare the recordings. if the groan is coming directly from the PS pump, the contrast in the recordings should be obvious.

aside from cleaning the screen in the PS fluid reservoir, and without dropping the cash and the labour to replace the pump,
... is there a better way to diagnose whether my PS pump is dying, or if there is some other cause of the noise and stiff steering?

this behaviour is fairly 'new', and samatha, my '92 previa, has about 215k miles on her

thanx in advance for any help or advice
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post #2 of 3 Old 05-07-2010, 07:54 PM
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I don't really have an answer to your question, but I believe that I have found some useful info.

My Previa did the same thing, and I also noticed that one of the front wheels will skid and skip on gravel as if the front diff was constantly locked in posi-trac or something.

I've been reading up and it seems that this problem is a bad viscous coupler in the transfer case. From what I understand, while turning, the outside front wheel will turn the front driveshaft faster which is supposed to not matter because the VC should be unlocked. Being mine is malfunctioning it is locked all the time, so the wheels will bind because they are turning at different speeds.

I have looked into a fix and an OEM TC is big bucks, as is a new VC. About the only reasonable option for me would be to find a used TC and install it. I've read that you can remove the front driveshaft, and lock the TC so that you are in constant 2WD. Here is a link.

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post #3 of 3 Old 05-07-2010, 10:01 PM
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To the OP...My steering got progressively stiffer over time. About 3 months. It was fine as long as I was rolling 10 mph or better. but at parking speeds and manuevering it was almost unusable. Then the squeal started. The squeal was in the later stages of development. I went ultra complicated just like you. And as well as you I felt the belt which was tight. Long story short...I changed the belt. It fixed the problem. The reason is because the inside track of the belt is rubber. Beyond that rubber is a felt like material that has no traction whatsoever. So when the inner rubber surface is gone you are left with a tight belt that looks and feels fine but upon removal and replacement I discovered why it no longer worked. That was about 240K miles. First belt replacement.

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