What would be easier?
 

I have a 97 Jeep Grand cherokee , i have some serious noises coming from the rear end, i managed to buy a rear diff from the junkyard same gear ratio as my dana 35 , my question is , what would be the best way to go about this. 1 just tear the old one out.
or 2. take all the gears and shafts from used one at place them in mine.
Is there any certain tools i need to change the gears .

Just swap out the whole rear. Changing gears requires special measurements and such. If you dont do it right you could end up messing it up and have to take it all apart again. Swapping out the whole rear is just nuts and bolts.

Ok , thanks, just was looking at that nasty track bar bolt and seeing visions of pb blaster all day. Wasnt sure i thought maybe everything would slide back in the rear end just like it came out.

Yeah, swapping the whole axle is WAAAYYY easier and less work. Four control arm bolts, two shock bolts, two parking brake cables, remove the calipers and rotors, and disconnect the brake hose. You should be able to have it done in a day.

I hope you bought a D35, otherwise you've got a driveshaft to match.

yes its a D35 , just opened the donor one up and did a inspection , not that i really know what i was lookin for but i didnt see any metal shavings . just trying to get all the old rtv off .

Look at the wear pattern on the ring gear. It should be bright and shiny in the center of the teeth and not near the edges.

I would invest in axle bearings and seals..

https://cimg6.ibsrv.net/gimg/www.che...960fc32425.jpg

Donor Rear end D35

Thats what the gears look like.

Hommer , thats the reason im changing the rear end , the bearings are shot in mine, and i dont have a press , or want to take the rear end apart to change front seal.

CArrier bearings are relatively easy as long as you have a shop of some sort to work in, worst part is cutting or grinding the old ones off if you have no press. Just be careful to reinstall all the shims just as you found them. Replacing spider gears is also not bad. Your wear pattern looks a little bit off there running off the end of the ring gear on the donor.

See this is my issue , ive had a rubbling noise coming from the rear end for about 2 years now, i was told it was the bearings, so i went and bought a rear end cause i didnt have a press, and i was told it requires special tools to take the gears out from current diff and replace them with the donor ones, my buddy suggested taking the axels out of the donor and putting them in the current one on the jeep , but i also have a bad front seal on that diff. so i dont know which way to tackle this , your saying you see some abnormal wear on the donor , i dont want to put it on the jeep and have issues. This is my DD. I dont have a shop just the front street. How do i tell if its the bearings bad or the pinion gear in the current diff. and which do you think is the best option to go for ,

First off, I understand the situation, but especially in a case like this you want to be certain you are fixing the right thing, and I think you are not. Otherwise as has been said before on here, you are not troubleshooting and just changing parts.
I would never tackle the rear end in the street. Are you sure it's not the parking brake dragging? Axle bearings ...I might try that in the street, if it wasn't odd-even parking, but not carrier bearings. Still would have to open the diff, take the lock bolt out, slide the pin out and take off the C clips on each axle, and then R&R the wheel bearings from each shaft.
I think you're in over your head working in the street, and advise against it, you'll end up with tickets and a tow truck hauling you away at $100/day storage at some lot. Fill it with oil and wait for a better opportunity. If it hasn't died after 2 years it will likely hang on some more. It is, after all, a Jeep.

Best case scenario? Take the donor axle to a driveline shop and get it rebuilt with new bearings, seals, and gears if it needs them. THEN swap it in. I know what it's like to only have one vehicle and need it for my job! There's a shop near me that does BIG trucks and they don't mind doing jeeps!

If you need them, a ring&pinion gearset goes for about $200 new.

i know its not the e brake , cause we checked that 2 years ago, and actually i dont have a ebrake we removed that to just make sure it wasnt the noise, its getting pretty bad i did put it off , cause i was unsure of my ability to do it, i bought new rear end sway bar links, new shocks , new brakes lines for when i do this swap , they been sitting here. but the noise has gotten worse, i was told by a mechanic that be believes it was the axle bearings , which is really why i started this thread, to figure out to just replace the whole 9 yards, or just pull the axles out and slap the new ones in. Im starting to hear a whinning noise now, i just filled the diff up the other day , and changed my transfer case fluid. i would take it to a shop but i dont have that money , thats why i just bought a rear end from junkyard. it was the cheaper route.

Do you have a dial indicator or know someone who has and how to use it? You can check the pinion bearings by measuring any end play or up&down play in the pinion yoke. There should be none or .001" at most. Those bearings are "preloaded" or installed with pressure holding them together. As they wear, they get looser. Once the preload is gone, they wear rapidly causing the pinion to move away from the ring gear and making it whine. This whine can go on for years and eventually the bearings will fail, usually causing them to explode. Bad pinion bearings can make the whine change in volume or tone on acceleration or deceleration.

An axle bearing usually shows itself as a rumble rather than a whine.