High pitch sound in my motorhome that is coming from the rear end

[TimJack]

My 1998 Winnabego Adventurer (Chevy P30 chasis) has a high pitch sound when I get up to about 45 mph and above. I have read that this could be the pinion gear and or the differential that may be bad and causing this. Has anyone had any experience with the pinion gear or the differential going bad? What kind of cost am I looking at to repair?

Thanks,

TJ

 

[madrone]

I don't think that is real unusual in truck chassis and differentials, my Luxor on an Oshkosh chassis does it and the original owner told me it did from the time he got it new. I don't think it means failure, wouldn't hurt to change the oil in it or at least check and be sure its full.

 

[DonTom]

I don't think that is real unusual in truck chassis and differentials,

My 4WD (my model is not capable of selecting 2WD) Jeep Grand Cherokee made such a noise, but only in slow turns. Could not hear it above 45 MPH at all.

Anyway, I changed the tranny fluid, transfer case gear oil,  and the gear oil in both differentials and then the noise reduced to almost nothing. I can still hear it a little, but nothing like before doing the above work.

Changing gear oil can make a difference in at least some cases. Good place for TJ to start.

-Don- SSF, CA​

 

[bigskymt]

  I'd opt for ring and pinion wear or misalignment. A good drive line shop can open the case (if it has an inspection pan) and inspect the gears. If your going to drain the fluid anyway it would pay to inspect. A P-30 should have that pan.
  The ring/pinion can be adjusted with either shims in the pinion carrier or torque on the ring gear. There are specs for that.  USUALLY a whine caused by ring/pinion is not indicative of future failure. If Acceleration/deceleration changes the 'whine' it's most likely ring/pinion.
  My '84 P-30 had similar issues.