Rear pinion seal
 

My rear pinion seal is leaking like crazy. How hard are these to replace? Do I need a real seal puller or can I just smash a flathead screwdriver into it until its deformed and pry it out? My other question is could this be caused by a bad u-joint because I do have a pretty good vibration coming from somewhere in the truck. It is most noticable when coming to a stop. I have yet to check wheel bearings which I will do tomorrow but Im not sure if thats it because it doesn't really happen around corners or at speed, just when I am coming to a stop. Another thing I noticed which may or may not be related is that when I am slowing down in 2nd gear and hit the brakes I hear a definite click/metal on metal sound coming from the front and I only hear it once right when I hit the brakes.

Yes. A bad u-joint will raise hell with the outer pinion bearing and that will cause the yoke to "slop around" and the seal does not stand a chance of sealing much at that point.
Yes to using the medium/big screwdriver to smash the seal into submission....I've done the same many a time also.
On level ground, place the tranny in neutral. Crawl under there and check the yoke for wobble. Good time to check the UJ for rotational slop also.
Remove the 4 bolts and check to see if the pinion nut simply loosened up.

PS- If you search for my name or "loose pinion" you should find a good threAD OR 3 ON REPLACING THE (damn cap lock key) seal...keep us updated on what you find...

Here's the thread I was thinking of that should help....
https://www.yotatech.com/forums/f116...acment-152859/

ZUK