2001 F150 7700, 10.25 in diff pre load

[Double-Eh]

I had to change diff fluid and front pinion seal on my 7700. If I read correctly all 7700 has the Sterling 10.25 inch differential. Fluid was not a big deal.

But the pinion seal requires removing the driveshaft, pinion bolt and yoke. I marked them all out (but didn't torque test resistance to turn wheels) and replaced a very leaky seal. I put everything back together. Put it all back so the marks would line up, but the rear end howls a bit on deceleration.

How can I remedy this problem? We're hitting the highway next weekend and I'd like to avoid a shop bill. Any experienced guys with these Sterling?

[TimeOff]

Had similar issue on a pinion seal change on a Ford F350 work truck once, howl right afterward. Has to do with improper torqued pinion nut, crush sleeve that gets changed after each time torqued I believe.

[Redneck 7]

When I change pinions seals I count the number of turns from the marked locations so you know how tight it actually was. Sorry I’m not much help for resetting your torque spec.

[hogie]

Would start with a new crush sleeve if it's over preload spec. Generally with used bearing 1 to 10 inch lbs and with new bearings 15 to 30 inch lbs of rotational torque. You need a dial indicator inch lbs torque wrench to do this with.

I measure preload before removing yoke or flange then put back to where it was . If you have to replace the flange or yoke then marking it won't help.

[ram crazy]

For the 10.25 diff. The rotating torque for used bearings is 8-14 in/lbs then you have to put a friction modifier in (Ford XL-3) then install a (XY-75w-140-QL) gear oil. There is a good chance the reason why you hear the howl is because you never added the friction modifier. What you should have done before removing the pinion nut is taken a rotating torque reading. A side note, when your doing the rotating torque make sure you have the axles removed. This will give you the correct rotating torque. There is a special tool that bolts to the flange that allows you the hold the pinion while torquing the nut as well.

[RandyBoBandy]

Originally Posted by ram crazy

For the 10.25 diff. The rotating torque for used bearings is 8-14 in/lbs then you have to put a friction modifier in (Ford XL-3) then install a (XY-75w-140-QL) gear oil. There is a good chance the reason why you hear the howl is because you never added the friction modifier. What you should have done before removing the pinion nut is taken a rotating torque reading. A side note, when your doing the rotating torque make sure you have the axles removed. This will give you the correct rotating torque. There is a special tool that bolts to the flange that allows you the hold the pinion while torquing the nut as well.

Absolute BS !! Friction modifier is used ONLY to coat the posi-clutch plates and that's IT... Mis-information does not help this OP

[ram crazy]

Originally Posted by RandyBoBandy

Absolute BS !! Friction modifier is used ONLY to coat the posi-clutch plates and that's IT... Mis-information does not help this OP

Friction modifier also helps with hypoid gear noise. This is not BS!

[hogie]

Originally Posted by ram crazy

Friction modifier also helps with hypoid gear noise. This is not BS!

Then why do you only use it with a locking diff? Ford doesn't ask for it unless it has clutch packs.

[ram crazy]

Originally Posted by hogie

Then why do you only use it with a locking diff? Ford doesn't ask for it unless it has clutch packs.

Ford recommends it in all 10.25 diffs. They say 8oz. of modifier.

[REMINGTON JIM]

IT is Only a FRICTION modifier for the clutch PACKs Nothing to do with with HELPING diff noise at ALL ! And its NOT used with the Electric Lockers either ! RJ

[Double-Eh]

It isn't the friction modifier. I added it. And it isn't for the howling noise, it's for the clutch packs un the limited slip. And that isn't my issue. No shudder. It's howling. Humming. Whatever. When I coast or break at speeds over 40 km/h ish.

I'll be replacing the crush sleeve and getting a rotational torque within specs.

It would be super ideal if the sleeve could come out of the yoke side of the diff... But we'll see I guess.

[nimrod]

On a side note, when your re adding the axle oil, tip the axle side to side, to get the oil to the wheels, then when this is done, add to the mark or bolt hole, this was done with a buddy had the wheel seals done on his dodge truck.