when do rear/front differentials absolutely need to be replaced? on 2006 Chevrolet Equinox

there is a slight humming noise in the front when driving the car. We are heading on a trip which is 500 miles round trip. the garage said front differentials with transfer case and rear differentials are needed. Is car safe to take on trip?

by in Kingston, PA on June 21, 2013
1 answer
ANSWER by on June 22, 2013
Theoretically, they never "absolutely" need to be replaced unless they are physically broken. And, unless the vehicle is 4 wheel drive or All-Wheel drive, there will not be a front differential or transfer case. As far as the humming noise, have it diagnosed by a good shop. It could be tire or front hub bearing noise. If the vehicle does have a front differential and transfer case, it could be gear or bearing noise from one of those as well. Take it to someone who knows what they are doing.