The dealership says the whole rear axle needs to be replaced for $2,500. Plus...

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My Xterra has 177,000 miles on it and the seals in the rear axle are leaking. The dealership said the whole axle has to be replaced for around $2500. In addition it didn't pass inspection due to emissions, possibly a bad catalytic converter. I just replaced both rear leaf springs with OME Dakar springs since the drivers side leaf spring snapped, this was the third time a leaf spring broke on my Xterra. I don't even go off-roading or tow a trailer or carry heavy loads. At least the new springs won't break again. Is it worth getting the needed repairs done or is am I just throwing money out the window?