I took the plug out of the diff housing to check and top off the gear oil and noticed a viscous, grease like mixture of metal flakes/dust and gear oil on the magnetic plug.

I realize that with 173,8xx miles there is bound to be some wear on the diff assembly, but is this of any significance that I should be concerned?

I also have that whine the 10th generation F150s are infamous for. I could replace the ring, pinion, and associated bearings for about $400 if I do it myself, but I do not have the tools or experience to preload the pinion bearing or shim the ring gear. I imagine that a shop will charge about $1200. Should I bite the bullet?

What say ye, F150 Online?

EDIT: Is the whine related to excessive wear?

 

whine is generally caused by worn out bearings. if you can do the job yourself, go for it! the average going labor rate is like $700/axle.

 

just change the fluid and drive it.

 

If you are referring to axle bearings, I changed those and the seals in the summer of '07. The most expensive thing was the synthetic gear oil Ford calls for. $16 a quart...was $80 after tax! Each bearing was about $20 and seals were $7.

Growing up on a farm, I know what bad bearings sound like and I do hear some "bad bearing noise" in the whine, but that can't all there is to it. In the research I conducted two years ago about it along with Ford's TSB on the matter, it seems that the ring gear, pinion, and all associated bearings have to be replaced.

Sooo...if you are referring to the latter then as I stated in my original post I just don't have the know how to preload the pinion bearing or shim up the ring gear. Good time to learn? Absolutely, but I'd have to find someone who knows how to do it and would be willing to lend a hand in exchange for a case of beer.

 

What is your opinion on using 85W-140 gear oil instead of the Ford specified synthetic 75W-90?

I ask as the synthetic 75w is $16/q where is the 85w is half that. I figure that if 85w is good enough to use in differentials and axles of my tractor-trailers and dump trucks, why not use it in a light duty diff?

When I changed my axle bearings and seals, I dropped the cash for the Ford recommended as I wanted to err on the side of caution, but if opinions differ, I may go the cheaper route.

 

you need a magnetic base dial caliper (makes life easy) to measure your backlash (the shim portion)

preload, i've gotten away with reusing the crush collar and just setting my rotational drag / preload to 13 in lbs. this was with the carrier out of the 3rd member.

FWIW, i run 80-90 wt oil in mine, but i dont have anything stock in the rear end except the axles themselves.

 

My 97 Explorer & 07 F-150 both call for 75W140 in the rear differential. Are you sure about 75W90 in yours?

I have been buying Red Line for 104.88 per case of 12, which is only $8.74 per quart.



Synthetic Gear Oils

Designed to provide the highest degree of protection and greatest efficiency for your drivetrain. Red Line provides a complete line of drivetrain lubricants which are optimized for differential, transmission, or transaxle use over a wide range of temperatures. Proper selection depends upon the manufacturers' requirements and whether the application is for passenger automotive, commercial, or racing use. Red Line Gear Oils contain polyol ester basestocks to provide excellent lubrication even under extreme conditions of high-loading and high- temperatures--their natural lubricity provide excellent slipperiness which reduces the sliding friction in hypoid gears to reduce wear and temperatures. The synthetic basestocks have a natural multigrade property, so large amounts of unstable thickeners are not required to manufacture our gear oils, which means that Red Line Gear Oils will provide a stable viscosity for even extended periods of use. Red Line also manufactures gear oils which can be used in limited-slip differentials without the use of additional friction modifiers.

75W140
Our 75W140 gear oil is a GL-5 rated product recommended for street-driven road car differentials where that viscosity is specified, providing excellent performance in both conventional and limited slip units. Popular in late-model Ford truck rear differentials as well as many other common models.

 

klitch....should preload always be set with pinion & crush sleeve & brgs only? what do u mean 3rd member w/out a drop out? i think of the old days or large trucks when i hear 3rd member.....! like the infamous 9" ford drop out. ........i'm contemplating instaling 410's in this 05 4.6 scab , this little v8 is pathetic. its been many yrs since i've been in a rear end....55 ford car, i think it was a 8" drop out.....rossford

 

4.10s is a good idea, many people do that.

what i meant by the 3rd member with the carrier out was, i checked my preload to be 13 in lbs with the carrier on the floor.

preload, if im reading your question correctly, yes in these differentials the preload only pertains to the pinion and its crush/bearing.

now if you change applications to something different, i'll say like a waukesha pd pump, then the story changes to each bearing's preload needs to be set properly or else timing will be off.