Jeep Repair: 2000 Jeep Suspension or Transfer Case???, jeep cherokee sport, death wobble

Question
Actually have 2 questions:
1) why are the headlights dimmer than normal cars I see?  I measured the voltage at the battery with headlights and A/C on (car running) and it is showing 13.8V, which leads me to believe the alternator is working.  The headlights aren't as bright as I believe they should be.
2) Here is the biggie!  Recently the 2002 Jeep Cherokee Sport started to vibrate at high speeds (60mph) and cause you to think the front tires were flat.  Stop and look and restart - problem goes away.  We had 4 new tires put on + a right front axle joint - but it is back!  Now we notice at very, very slow speed (an crawl at idle) that we get a very strong vibration at the left front wheel (driver's side).  It almost seems like the vehicle is in 4 wheel drive and you are making a sharp turn - the axle kind of "skips."  Could something be going bad in the transfer case that is causing the vehicle to want to go into 4 wheel drive - even though the indicator is locked in 2 wheel?

Thanks,
Keith

Answer
Hello Keith,

  As for the head lights, the voltage is correct. What I would be looking at is a set of OEM type bulbs, as the ones you have now may not be of the correct wattage. Also make sure the headlights fuse is the correct one. On to the vibration. Nearly every Jeep Cherokee develops something called "The death wobble" at speeds of 60 MPH or more. Here is a through explanation of this problem and cures:  Something else, many Jeeps will indicate 2WD when you are actually in 4WD. The only way to tell for sure, is to go under the Jeep, take the nut that holds the linkage plate to the transfer off, and take a adjustable wrench, and turn the transfer stud that comes out of it, into 2WD. Another thing that may be going is the CV joints if you have them, or the U joints, depending on if you have comand, quadra, or select, TRAC. One way to check the CV or U joints as well as the transmission, is to put the brakes on firmly, and put the Jeep in drive. Keep the brakes on, and rev the engine to 1500 rpm or so. If you hear vibration or clicking, then you know there is a problem in the drive line. I hope this helps you. Let me know if you have any other questions. Good luck with the Jeep! --Jeep4x4man