smthellman

I'm new to this - so bear with me!
I have a 2004 Grand Cherokee Overland with a high speed vibration (75+) that is present on both acceleration and floating the gas. Bad enough that the rear view mirror actually shakes so bad I can't tell who is behind me. I also have a high speed hum that gets higher the faster I go. When I remove the front drive shaft - the sound is there, but the vibration is much less; still there, but very minor.
What I have done: new front axles, new tires, balance / rotate wheels and tires, changed both diff fluids, replaced pinion and carrier bearings (front only), replaced all u-joints (front and rear drive shaft), put in a new (used) front drive shaft (no real change between drive shafts), replaced transfer case with a used LKQ case - fixed the 4-wheel drive problem, but not the vibration and noise. When letting off the gas, the hum does become louder.
No metal flakes in either differential fluids during change - no pitting on the gears noted. I'm at a loss as to the next direction to go. Jeep dealer wants around $2,500 to replace front differential and rebuild transfer case - but I can't justify spending that kind of money on something that I have just done.

Next step?

Thanks,
Shane

docmedpros

Ball joints? Wheel bearings?

smthellman

I did the front wheel bearings (forgot to tell you). The ball joints feel solid when on jack stands. No play in wheel when pressing top / bottom. The tire shop suggested off-center ball joints because they told me that the jeep is "off in the front". I have no pull toward any side at any speed.
Still think ball joints are next step?

docmedpros

Only reason I suggest ball joints is because in my experience with vibrations(not in my jeep but my car) it was the ball joint on it's last leg. It was giving the sane symptoms you're referring too. I went through a number of different parts until I replaced them. Once I did my vibes were non existent

smthellman

OK - good idea. So - I started with the driver side ball jt replacements. The upper joint took around 2 hrs to get out (rented ball jt press from Autozone) - FINALLY got enough pressure to get the joint out - however, it literally blew up. The stud bolt shot through the ball joint housing - leaving the housing still in the steering knuckle and axle! Heated it up and got the rest of it out. On to the lower ball joint. 1 pickle fork, 3 pry bars, 1 crowbar, 1 ball joint separator, 1 can of PB blaster, and 4 hrs of hitting the side with a hammer while under pressure - the lower joint CAN'T be moved by human force (at least mine). I'm about to just grind off the entire steering knuckle / spindle and then try to press out the lower from the axle. I can't get a good angle on the lower ball joint without removing the steering knuckle / spindle.
I can get a new steering knuckle for $120 online....save the 4 hrs and money in tools while getting a brand new knuckle.
Any ideas before I start up the grinder?!?
Thanks again,

Shane

docmedpros

So for replacing ball joint ons on my XJ I've found removing the knuckle and putting it in a vice so I can get better approach angles on it. A **** ton if heat and constant pressure along with patience and some curse words goes a long way. Now if you have the coin or just need/want new knuckles replace them. Good luck