Ford changed the viscosity of the oil to get rid of the whine as "pinion leak" (under warranty) but the problem is much more than that; there's physical leakage. I can't hoist the car to see underneath but black oil in middle is obvious as another fellow with the pinion leak topic. It's in the shop today again. The whine occurs exactly at 40 mph (60 kph) only at acceleration at that speed and is audible with radio on it windows down. It doesn't happen during deceleration. My Corsa xtremes have been sitting in the trunk for 2 weeks waiting for this to be resolved.
For the record I have 3.73 6mt.

Problems I had so far are:
Engine knocking tsb: new short block replacement
#2 and #8 misfire
3.73 whine and pinion leak

 

Whats the picture of? Garage floor with differential fluid on it?

 

yes thats the only proof i have since i cant get under

 

Hey HizliBullet,

Your Mustang is in good hands with our Ford-Certified Technicians. Is it at a local dealer? Please let me know the details, including the current odometer reading. I'll see how to best assist on my end.

Mariel

 

updated with picture.

thanks mariel ford already ordered parts, its underway. the problem is differential gears, maybe its premature wear, dont know.

 

got my car back from the shop, heres the summary of the job

CAUSE: K02
4205A REAR AXLE ASSEMBLY - IN VEHICLE DIAGNOSIS
1 CR3Z*4209*B GEAR AND PINION ASY
3 CXY*75W140*1L OIL REAR AXLE
1CXL*3* ADDITIVE OIL FRI
1 TA*29*SEALANT - SILICONE
1 3C3Z*4663*AA SHIM - DRIVING PINION
3 4R3Z*4B496*AA BOLT

4205A4 REAR AXLE RING GEAR AND PINION SET
REPLACE 4209