I have a loud whining/howling noise on the highway. It starts at 70, is loudest at 75, and almost goes away over 80. It goes away if I let off the gas. Is this possibly the front diff?

 

Do not drive it over 65.

Change all your diff fluids ASAP.

 

I already did. All the fluids were pretty black.

 

dID YOU GO WITH THE HEAVIER WEIGHT?

 

75w-90, what is your suggestion?

 

Check your wheel bearings and swival ***** for grease also. And check the Ujoints for grease As far as gear oil that weight is fine.

 

Check you're t-case fluid too while at it(same oil as diff's).

 

I changed all the driveline fluids. I am pretty sure it is coming from the front. It sounds like it is around the passenger side floor. I think I can hear it if I put the pass side window down, but I may be wrong about that. I just tightened up the wheel bearings and greased the u-joints. Is there any kind of additive/ special fluid I could try?