My jeep developed a bearing roar from 30-65 mph. I orginally thought it was a ujoint so I rebuilt both driveshafts....that wasn't the problem.

I took it to the dealer and they told me the bearing whine was my transfer case so I bought a rebuild kit and rebuilt it (new chain, bearings, seals)....that wasn't the problem.

After taking it to a friend to help me solve the problem we figured out that while in 1st and 2nd gear there is no problem. However, when in 3rd-5th you hear a really loud bearing roar.

We got the jeep up to 30 and put it in 3rd and the noise was there, however when you rev it and drop it into second gear at the same speed the noise goes away.

The funny thing is that when you drop the jeep into 4wd the noise nearly disappears.

When I say roar, it is really loud when going 40-55mph and once in 4wd it is back to almost normal.

What could this be?

I learned that it is cheaper to go get another tranny than to buy new gears from jeep. before I got rid of my ax-5 my fith gear had a weird noise so I put bigger tires on so I didnt have to use that gear ha

i have an ax-5 and np231 for sale.. real good shape. no whine, no grind, still has fifth gear :) well maintained.