I've been a member here for a while, but this is my 1st post. Usually I find an answer to any issue I have through the search. This is my 20th year anniversary with my girl...a fine 1996 black beauty. I've broken a lot of stuff over the years...but I do know the "feel" of her. Ok problem: I get shaking on the front end between 30 and 45mph, before that and after its smooth. I have some " cupping on the passenger side tread before and after the work done. I've read every post on the Internet on the issues...I can't solve it. I have 38 super swampers on newer alloy rims, I just had alignment front to back rotation, balancing done along with new shocks, ball joints, pitman,idler. Didn't fix a dam thing other than I didn't realize how sloppy my steering was. 17 years no shaking last 3 progressively getting worse. Anyone have an idea what I could try next?

 

If the steeing parts are worn and you replace the idler and pitman arm those are the only parts that dont affect the allignment. I would have also done both tie rod end assmeblys as well. Then get i realigned. Make sure they torque the control arm brackets to at least 300 pounds with lots of red locktight. My first guess on the shaking would be that the super swamper tires are out of round. Jack a wheel up about 1/2" off the floor and spin the tire. If the tire is out of round then the 1/2" gap will fluctuate. Then your tires would be egg shaped. Normally out around tires will shake all the time. Could have damage to a tire sidewall causing tread separation. Also grab the tires while in the air and shake in ever direction and feel for any play. Cupping tire wear is caused by a bad allignment. The camber angle could be off due to worn /loose control arm bushings.
Where are you located? Maybe there is someone in the area that could give you a hand looking at it?

 

I have a 94 and have also owned it for 20 years. First off I had a set of Swampers that looked good but were awful tires. Wore out rapidly and I could never keep them balanced. I did all the things you did once when I had the "shaking" and finally I put new shocks on and it solved the problem (did not have Swampers on at the time). I forgot the name but I got the shocks from military surplus.