Recent noticed a whirling noise coming from the front of the car. Pitch increased with velocity, but not RPMs. A mechanic diagnosed it as a worn front differential. I have a long highway trip coming up and want to know if this will stress it to its breaking point and I’ll be stranded. Also, what should it cost to repair. This mechanic said an overall is $1K. 267K miles on a 2001 Jeep Grand Cherokee with the 4.8L V8 engine. Never had a work done on the front differential. Thanks!
1k seems like a fine price, you risk alot more in repairs and being stranded imho by skipping the fix.
Why is your front always differential turning ? Is it always engaged or can you disengage it? What type do you have ?
The front diff is always gonna turn regardless of there being power to it or not. What supplies power is the transfer case. In the 4.7L I believe its the quadra-track t-case which means all wheel drive. I had a wheel bearing go out on me a number of years ago in this same vehicle except mine was the I-6 4.0L edition. It lasted for quite awhile before getting it replaced. What I found was yes it did get louder as I went faster, but even more profound was when I went around a corner, it got louder and as the weight of the vehicle shifted back and forth it would change in volume. See if it does the same for you. If it does, its likely a wheel bearing. Get it replaced as soon as possible.
267k miles? How about a low mile used replacement diff/housing?
I agree with @Stoveguyy - repairing a diff is exacting work, replacing the entire axle assembly is simpler, and a used one in decent shape will have MANY miles left on it.
I replaced the rear of my second car in a dorm parking lot…
have you kept up changing the gear oil in your diffs?
If the differential is indeed the noisy unit, I like to say to keep on driving. Maybe I’m right, maybe not. If it’s the transfer case then I don’t know enough.