So, my car has made whining noise at highway speeds on occasion (only 3 times this year). I end up pulling over or taking the next exit and the noise goes away when I slow down to 15 mph. I mentioned this to the dealership (I had a coupon for a cheap oil change there). They said that my front differential is toast and needs to be replaced, and quoted me $3.8K. I am definitely taking it to an independent shop next week for another opinion. Is the differential something that can be salvaged? I know the dealership always tries to scare their customers with worst case scenarios.

 

Depending on the milage cheapest route. I probably to change out the fluid, and see if it helps. Worse case scenario is the diff will have to come out. By what I've seen it's not a pretty sight getting the work done.

 

Try Amsoil Severe Gear Synthetic Extreme pressure 80W90 for your differential. I changed out the rear diff in my IS350 and it really smoothed things out. It's good for 100K

 

IME diff's that whine on accell or decel, have issues and can not be salvaged. Likely need a bone yard swap. That said, dropping the fluid will let you know. A while back a guy had some noise and dropped the fluid and it is 95% water.

What is the history on the vehicle?

 

From my experience I think most people neglect the differential when it comes to service. I've known lots of people with RWD and AWD who didn't even know it is a serviceable part of the car. In fact my service manual only mentions service for the ISF (probably because of the LSD). I'm afraid to even think what the condition of that guy's diff being lubed with water...

 

Hey dad, me and friends are going to borrow the car.... Haha!

 

155K miles and I pushed off having the differential fluid changed from my last visit. Guess I am paying the price on that one. This will be the first bigger repair on the car besides the water pump last spring. I know there really is not an answer since I cannot show a clip of the noise. I was not sure if the bearings or pinions can be replaced without having to get an entirely new differential. Multiple times the dealership does not even try to fix a the part and just automatically wants to put in a whole new one. Happened with my calipers that seized and a shop fixed the part for only $100 while the dealership wanted close to $1K.

The place I am taking my car to next week specializes in Lexus and offers reasonable prices. Fingers are crossed until then. I see that a swap from a salvage yard is around $200-$300 for the part. I assume 6-8 hours of labor...or am I underestimating the amount of labor?

Thanks everyone for the input so far, and I know I should have not been a bonehead and just did the preventive maintenance. But 2020 is the year that everything has to go wrong...