how to tell if a pitman arm is bad?

New to me truck 1992 4wd 3.0L V6, auto, 150K miles. I don't believe it was abused before--street tires, no mods, and it doesn't appear it has been in an accident.
When I bought it, I took it to a mechanic for an inspection. The mechanic came back with a list of things that need to be replaced. I had them do the steering stabilizer, but they also said the idler arm and pitman arm need to be replaced. How can I diagnose this on my own?
When I asked point blank, this mechanic didn't know if the 3.0L V6 is an interference engine or not. There were a couple other things that were questionable about their inspection, so I don't completely trust them.
I don't want to trash my new tires by having bad steering components, or drive something unsafe/unreliable.
Is there a sound or a wobble if either (or both) the idler and pitman arm have gone bad?

 

With the engine off have someone inside turning steering wheel side to side (only go to bind just before the wheels move) get underneath it and grab all the joints in the steering system. they should all feel tight and move as one if you feel any movement that component is bad. Start with outer tie rods and move inward.

 

Where are you located

 

92yotapu, I'm in Maryland. Thanks for the info. I was planning on getting it on a lift later this week to grease it up and inspect the play in the steering components and test a wheel bearing.
Does 150,000 sound like a good replacment interval for the idler arm and pitman arm? I owned my 95 4Runner from about 175,000 to 200,000, but the previous owner overhauled it. I never ran into steering issues.

 

It just depends how you drive it and what you use it for. When you do this test do it on the ground. Its called a dry Park test

 

after waiting for the weather to get better, I finally did the pitman and idler arms. I probably didn't need to do either (I believe my former mechanic was lying to me when he siad I needed these, along with the brakes (pads had 75% remaining, CV joints (boots aren't even cracked and there is no noise ever), center support bearing, wheel bearings...).

However, the old ones are off. I've gotten the new ones on, but barely. The pitman arm has not slid up the splines to the position where the original one was seated. I've tried spraying this with PB blaster and wailing on it with a hammer, but can't get it to budge. Any suggestions?

Also, my steering wheel is now about 1/4 of a turn to the right. I need to pull the pitman arm off of the steering box and rotate it a few splines to get the steering wheel closer to center. However, I don't know which way to rotate--should I spin the pitman arm (using the splined end as the center) clockwise or counterclockwise?

 

Never hit a ball joint, pitman/idler joint, etc., with a hammer. It will damage them.

If you didn't notice any slop in the joint, when you replaced it, it was still good.