The rear main seal went in my 1993 chevy k1500 4x4 and the rearend immediaetly started making a grinding noise i replaced that and the the pinion seal went replaced both filled and it is still making the grinding noise. what am i looking at????

Joe, Could be a few things, U joint, E brake shoes falling off inside rotor, bad bearing in diff. better take it into a good tech. and have checked. too hard to diagnose from here. "Check the attached links,instruction and guides, Good luck
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Grinding noise Chevy Silverado and what caused it
So the front seal on my 2004 Chevrolet Silverado rear Diff was leaking so...
http://www.fullsizechevy.com/forum/general-discussion/technical-maintenance/415961-grinding-noise-coming-under-truck-rear-truck-help.html
Understanding and Diagnosing Rear Differential Noise Fuel Friction An...

Sounds like your rear end may be going out, check your diff.

Check drive shaft assembly for worn u-joints.if OK check for worn pinion bearings or loose pinion nut.This can all be check shaking drive shaft at each end and looking for slop in u-joints or pinion flange.

check the ring gear in rearend for metal shavings or any damage

side carrier bearings in side rear end that is do to leak of rear end oil due to bearing small leaking from pinion seal, ps check (side to side bearings , will not make sing at low speeds only high way speeds above 55 or more,

yes you will you have answered your own question ,eventually the wheel bearing will need changine when the noise becomes unbearable

what type of noise?
have you checked the fluid?

if its a grinding noise while driving it could be choppy tires carrier bearings or axle bearings.

if its a whine while accelerating or decelerating than it is pinion angle.

if you can safly get both rear tires off of the ground than start it and put it in gear, try to locate the exact location "center chunk or out far in axle tubes" make sure vehicle is secure and safe befor climbing underneath.

You cannot check universal joints with the driveshaft under tension. Trans needs to be in neutral (wheels blocked or on jackstands)
If diff is noisy, check gears by removing cover and checking lube for metal debris, gears for "sharpening" on edges. Generally it is cheaper to replace unit with one from a scrapyard. Any work regarding bearings or gears requires precise depth and lash adjustment or the unit will quickly fail again.
Universal joint failure will cause a "clunk" when engaging reverse or drive and also can cause vibration similar to out of balance tires. Worst case is a rhythmic squeak while going about 10-20mph.

Is the rearend blown into peices? if yes replace the whole thing. If not put it in reverse and have someone look to see if the rear driveshaft is spinning. If it is you more than likely need a ring and pinion set in the rearend. If it doesn't spin the problem is in your transmission not the rearend.

well i had the same problem everyone told me the clutches in the rearend were sticking making it stick in positive traction (only your passanger side rear wheel pulls unless you start spinning then a type of clutch engages the other side so you have traction then when you stop spinning it disengages it should never be engaged if your on pavment) now you can do what i did listen to everyone when they tell you its normal or you can take it to someone with experience now and save yourself some money cause it will start popping then it will get some viberation then next it will break the clutches and when that happens you will have to replace the pinion,ring,and the spider gears as well as the clutches.make sure you have pleanty oil in rearend if you dont add the limited slip conditioner it might free clutches up but if i had it to do over id put it in the shop or stop driving it before i broke something hope this helped