I changed out the PS front axle and differential seal on my 03 with 115k miles a few weeks ago. just a couple of random thoughts---
1. I only lost a few drops of Diff oil when replacing the axel and diff seal - I went ahead and changed the diff oil while I was under there and mine had a "normal" amount of shavings/ metal sludge attached to the magnetic drain plug. I say normal as there were no chunks or greater than 1/2 inch shavings. The magnet on the plug is there to collect the shavings as this is normal wear on all differential gears.
2. I don't think that removing or reinstalling the axle from the diff can be done incorrectly, unless the axel was not fully seated into the diff. This can be confirmed by crawling underneath to to see if there is a significant difference in the gap between the dust seal and the diff on the DS vs. PS. if not fully seated this could cause the whine you are describing but should have been readily apparent when they looked at it a second time. The seal is easy to change out when the axle is removed and if the seal was done improperly, it would leak - not cause gear whine.
3. did they damage the needle bearing in the hub when they installed the axle back into the hub? Could cause the noise / whine you describe?
At this point I think I would ask the dealer to once again drain the Diff fluid - If there are significant new shavings on the magnet, then most likely the Diff gears are definitely on the way out.
If the magnet is clean, then the cause of the whine might be the New CV axle they installed or coming from the hub bearings or needle bearing.
I doubt changing out the axle caused damage to the diff. gears, but anything is possible. Running it without diff oil would definitely ruin the gears however....
If you can't get any satisfaction from the dealer or toyota customer assistance, Do Not pay the dealer for a New differential or replacement gears - It will be much cheaper to have a used diff. installed - There are many low mileage examples available on car-part.com
1. I only lost a few drops of Diff oil when replacing the axel and diff seal - I went ahead and changed the diff oil while I was under there and mine had a "normal" amount of shavings/ metal sludge attached to the magnetic drain plug. I say normal as there were no chunks or greater than 1/2 inch shavings. The magnet on the plug is there to collect the shavings as this is normal wear on all differential gears.
2. I don't think that removing or reinstalling the axle from the diff can be done incorrectly, unless the axel was not fully seated into the diff. This can be confirmed by crawling underneath to to see if there is a significant difference in the gap between the dust seal and the diff on the DS vs. PS. if not fully seated this could cause the whine you are describing but should have been readily apparent when they looked at it a second time. The seal is easy to change out when the axle is removed and if the seal was done improperly, it would leak - not cause gear whine.
3. did they damage the needle bearing in the hub when they installed the axle back into the hub? Could cause the noise / whine you describe?
At this point I think I would ask the dealer to once again drain the Diff fluid - If there are significant new shavings on the magnet, then most likely the Diff gears are definitely on the way out.
If the magnet is clean, then the cause of the whine might be the New CV axle they installed or coming from the hub bearings or needle bearing.
I doubt changing out the axle caused damage to the diff. gears, but anything is possible. Running it without diff oil would definitely ruin the gears however....
If you can't get any satisfaction from the dealer or toyota customer assistance, Do Not pay the dealer for a New differential or replacement gears - It will be much cheaper to have a used diff. installed - There are many low mileage examples available on car-part.com
