Front End Shake Coasting at Highway Speeds

[BobFunGhoul]

Hey everyone, need a little help here. 1997 K2500 Suburban 6.5l T/D. When I first start driving, she has a nice smooth ride @ 60mph and below. After I get about 30 miles under my belt, and anything above 60 mph, here are the symptoms: 1. Cruise control set, uphill, under load, slightly banking right - Cadillac smooth 2. Road levels out, cruise control starts to back off - she starts to get a front end vibration that you can feel through the cab, not in the steering wheel, 3. Same conditions as #2, but going straight or slight left - the shake gets worse. 4. Downhill, cruise backed off in a coast - she rattles your teeth out especially in a left bank.
I know that I have a worn pitman arm and 2 tie rod ends that I will hopefully be replacing today, but I don't think that's the problem. I also get a brake pulsation in the left wheel at highway speeds; again, this is only after I have been driving for about 30 miles or longer. The truck runs fine until it is up to operating temps. Thank you all in advance and I hope everyone had a nice Thanksgiving.

[DaveBr]

You don't say if your truck is 4x4 or not. A friend of mine had a similar issue. Turned out the needle bearings in his front diff were gone. I remember the vibration was not like braking with a warped rotor but a much faster and intense. Hope this helps.

[HH]

Check your upper ball joints.