Differential / Rear end help

For years I prayed for enough money to get a new (or at least new"er" vehicle). Finally got a super clean used 1998 Dodge Ram 1500. Nice truck, (even if it was the only automatic transmission I had ever owned)
now...
A year later, it sounds like the rear end is about to go. Is there a fix or adjustment (that is affordable??)

It started as a noise that sounded like tire noise.
After a month of listening to that noise slowly start to turn to a whine - finally - I can feel the pinion just getting a little warm. Not hot, just a little warm. (not even warm enough to know for sure it's not normal, really...)
If I jack up either rear wheel and turn it... I hear
"grrrr-rrrr-rrrr-rrrr". (if you can roll your "r" in the back of your throat - you can make the noise perfectly)

Felt the housing by each wheel bearing, nothing. I'm afraid it's the pinion bearing - or - the pinion/ring are both worn terribly, or it's just out of adjustment. I can only tell you this is the 3.5 ratio, 9.25" version...
Check and Adjustment procedures you can do in your own driveway would be a really, really big help. Otherwise... it's off to the wreckiing yard, to buy some other rear end, and see what happens...
Jason
is that DANA ?? or Chrysler?? Any difference?? the Dodge house wants a minimum of 825 $$ - which I don't have - but claim they might be able to "fix it with standard maintenance"... but won't know till they look at it...

the only advise I can give at this point is to pick up some gear lube, and pull of the dif cover and visuaily(sp) inspect the teeth of the ring and pinion gears.
also, you can try grabing the yoke(where drive shaft attatches to the pinion shaft) and see if there is any play.
also, this is just a thought, but do you know if you have a limited slip dif.? if so, the "grrrrr-rrr" noise could be worn clutches in the dif. if that's the cause, changing the fluid and adding the propper additive may take care of the problem.
also, the 9.25 is a dodge/chrysler axle, they only put dana axles in the 2500 and 3500 moddels.

just had another thought. are you sure that the "grrr-rrr " is coming from the dif? there is a chance that it could be a worn axle bearing(the ones at the end of the axle neer the wheel). those can be checked by jacking up the tire and seeing if there is any play(up and down/ front to back)
good luck,
Keith

Well, I've already put in about two teacups full of std. gear lube - then the thought crosses my mind these new cars might need something special. One of these websites says use 75W90 5010320AA... is that something special? The lube I put in seems to be "seeping" around the rubber plug... (probably cause I filled it all the way to the bottom of the hole...)
No shake that I can get at the input, or at the wheel brgs...
Also the tag under the hood doesn't say anything
about "limited slip"... this is a very OEM 1500 SLT extended cab. They made a bajillion of them. Was the limited slip thing std.?