Power-Lok Differential got hot

[hawkeye2]

1998 Eddie Bauer AWD V-8 119,000 miles.

Had the rear diff gear oil changed. Lube place used Valvoline 75w-140w fully synthetic. This matches owners manual lube spec. BUT they did not put in friction modifier as REQUIRED by owner's manual and specifically requested by me. I showed them the owner's manual lube spec pages and footnotes. They said the Valvoline bottle claimed to have all necessary limited slip additives.

Next day, On a long(600 miles), fast(75-80mph) highway trip , the rear differential started making really bad noises and had a hot oil smell. Another driver actually pulled along side to point out I had a problem. Smoke from under the car!
I had to pull off I-5 (Seattle 5 o'clock traffic) and get a tow home.

Did the LACK of friction modifier cause the overheating?
It seems the clutches would rub hard instead of sliding past.

I will open the cover today and survey damage.

PS: Lube store owner is working with me on this, but I need to verify cause of damage. So be fair with your answers. If it is my problem I will say so and get on with life. The lube store owner is willing to pay if it is the fault of their procedure.

I plan on putting in a complete low mile(50,000) axle from a totalled 97 Explorer. I found a matching D4 code axle (3.73 and Power-Lok) at the local reputable salvage yard.

Fastest fix to get me back on the road.

 

['97 V8]

Yes it would be the shop owners fault. Just make sure that the axle from the totaled X isnt tweaked in any way.

 

[FordLover]

yeah, seems fishy that the axle was fine, took it in for service, soon after problem develops. I'd guess that they didn't put in enough fluid, wrong type, or something else.

I wouldn't think leaving the modifier out would cause DAMAGE, especially while driving high speed on a highway (the differential action isn't being utilized while going straight, meaning the friction plates in the Factory trac-lok rearend aren't being used, they are just along for the ride.
Leaving the modifier out could cause the limited slip action in the axle to work less effectively though.

 

[hawkeye2]

The Traction-lok is ok. oil was fine . After inspection I had 3 problems
1. front driveline CV joint is bad and noisy. I will replace
2. left rear brake rotor rubs on caliper frame when turning right because wheel bearing is wearing out. I will replace both sides.
3. I replaced all 4 brake rotors and pads.