front end problem?

[jrobb913]

i have a 99 GMC Jimmy sl with a 4.3l V6, ive recently noticed theres somthing wrong in my front end, it hums all the time and it vibrates the entire vehicle, once you hit about 80 km/h it starts to get bad, i was thinking it was a bearing but im not to sure.

 

[ferretx9]

You can jack up 1 side and then spin the wheel , then do the same to the
other side .

It might help narrow the problem down.

 

[jrobb913]

what exactly am i supposed to be looking for? i have both sides jacked up and they both spin but are kind of tight, i cant really hear any noise comming from them.

 

[ferretx9]

Not being there in person , and based on what you have described and the
" test " results given ( they both spun the same and there wasn't any clunking ) , my best educated guess is -


the hum is coming from the differential ( have heard / read of this complaint more than once ).
check the fluid level .

the vibration is from a tire(s) being out of balance .

Have them re-balanced and rotated . Ask if they had to add / subtract any weights .

The worse that can happen is you just eliminated 2 possible culprits for the least
amount of money , and tires should / need to be rotated / balanced on occasion anyway so you're really not out anything in the long run.

 

[Z15]

Is this a 4x4? If so, check the front driveshaft for bad u-joints. If they go bad will cause a terrible vibration under power.

 

[jrobb913]

ok so i was looking on youtube, and i jacked up both sides n wiggled them from top to bottom, the passenger side is tight and the driver side has a little bit of play, now for the diff, i pulled the plug out and i couldnt feel any oil, so i added about 1 liter of oil, give or take, and i took it for a drive, that somehow fixed most of my vibration problems, so im pretty sure it is a wheel bearing on the front driver side i need now, how would i go about checking for bad u-joints?