Rear End, transmission rebuild costs?

[Cutshaw]

I recently picked up my third jeep wrangler. Its a YJ 92 6cyl 5 speed. I now hear a loud whirl when I have my foot on the gas driving down the road. I start hearing it around 25mph, if I'm in 4th going 30-35 mph its really loud. It continues up to 70mph. Its coming from the back end. I was quoted $585 labor + parts to rebuild the back. I dont think they actually took the cover off to see if there were any visible problems inside. They added fluid and its not as loud now. Any ideas on what it could be so I could get an idea of parts costs? Another place quoted me $433 labor + parts. I was told at the second shop that if it is the bearings (the guy thought it might be that without seeing it) that the parts will be around $350. I haven't had the second shop look at it yet, but they want to at least pull off the cover for a better estimate. Do these prices sound right? Another problem is the transmission. The 2nd gear grinds when I shift into it. At the first shop they think its the syncro, and quoted me $325 labor + parts. The second shop quoted me $556 + parts. Do these prices sound right? Is there any reason why I should have both problems fixed at one shop? I was going to do the cheaper at each place, I still have yet to call around to more places. I was thinking I should have them pull the transfer case while they have the tranny is out to see if any parts are messed up in there for a possible rebuild. Can anyone recommend a shop/person/home mechanic in the mid michigan area that could beat these prices? Mount Pleasant/Lansing/Jackson. The things I'm going to do myself in my spare time to the jeep are brakes, exhaust, top, air filter, tune up, cd player, rust repair. Possible carpet, larger rims/tires, and lift. Any home mechanics interested in helping restore a YJ? :) Any advice would be appreciated on my underbody problem that I cannot do myself!

[Bull]

The tranny I have no clue about, but the axle sounds like the problem that I was experiencing with mine. I had to replace the bears on one side of my axle for similar reasons. The only difference is that I actually ran mine to the point of breaking. I didn't have the tools to do it so I took it to a shop, the parts only ran about 20-30 dollars and the labor was only about 2 hours (at the most). I would suggest that if you aren't going to do it yourself take it to either a shop you know and trust, or a nationwide chain where they will guarantee the work so you won't be coming back with "new problems" 300 miles down the road.