2002 GMC Sierra - Steering Problem

I too would guess it is the valve.

ditto

Yes the steering box, which is a manually assisted servo acuator. The simple solution is to replace the unit complete and be done with it. Repairs are difficult on these units as they very seldom fail. I have seen one or two that broke the servo shaft and went "hard over". Luckily know one that I was involved with this was injured, but....

Correct, I have a 2004. Same problem and it was indeed the steering box.

I believe GM was using rack n pinions by 2002 in pickups and the trouble you describe is common for a "rack". It is also possible but less common in the old style steering box.

And a Hello From up the street Oregon Tinker. You in Eugene?

I have exactly the same problem with my 2002 GMC Sierra. Did it turn out to be only the gear box or did you have to also replace the rack and pinion also?

Thanks for the replies folks, that incident was about a year ago. I bought a seal kit for around $62, removed the battery, some wiring and hoses, made an access tunnel using bungee cords to hold stuff back and did open steering box surgury on it! It was very difficult but it worked. One of the seals had smeared off between the left turn and tank passages. The seals used to seperate pressure, return to tank, left and right oil passages are made of a green cardboard like substance and they don't like to stretch. I was able to lubricate the spool and the seals with tranny fluid and roll them into the grooves using an o-ring removal pick set. The fiberous seals had stretched and didn't want to duck fully into the grooves which took many minutes of working the housing back into place. The job took four hours but has worked well for the last 15,000 miles or so.

OT