Vapour Trails

I want to add an extra bottle of friction modifier to the rear differential. I have the car jacked up but I'm not sure where to add fluid. On the right side (viewing from the rear) there is what looks like a vent with a loose cap, is this the point of addition? Help.

moosestang

You could unscrew the vent fitting and poor it in that way, but i'd probably just remove the fill plug on the front of the housing. On second thought you might get gear oil coming out unless you can raise the front of the housing. It's usually filled until oil starts to run out the fill hole.

If you unscrew the vent tube, be sure to clean around it first. There's probably some dirt under the vent just waiting to get in your axle.

Vapour Trails

Thanks, I did eventually find the fill plug. I can't say things really worked out. I removed the fill plug and fluid began to seep out, so I replaced the plug loosely and lowered the car to the ground. I removed the plug again and started to add the friction modifier but it began to leak out after about 1/2 the bottle was added. So I just replaced the plug and quit. I guess this fix only really works when you totally drain the fluid. I was hoping there was enough capacity to add this without overfilling, there wasn't. Hopefully what was added will cure the noise, otherwise I guess I'm completely changing the fluid.

07BOSSGT_S197

gear whine from FRPP????? hrm who put them in?

howarmat

if one bottle of friction modifier is already in there you shouldnt be adding more.....im guessing the install is not correct

sleeper2

I agree with the above statement, one bottle of friction modifier is all you should need.

Sleeper2

HazardSports

Did you consider a small diameter tube to drop into the fill and use suction to first remove the volume that you plan to add ?

Vapour Trails

I should update:

Adding that half bottle cured all diff noise when making tight turns (u-turns in particular).

This was not about gear whine or the 4.10s, it was the clutch packs, there is a tsb to replace them. Some members indicated adding more modifier would work, and it did. I'm satisfied. Lately the ford techs have been causing one problem each time they fix another, the last thing I wanted them to do was open up the diff.

Gene K

Strange... Im only running 1/2 bottle of Friction Modifier after my 4.10 install..... The silence is deafening. No chatter at all.

grampa_stang

I'm need to add some myself. I haven't been under the car yet. Can someone give me a heads up
as to where the fill plug is located and what size wrench/socket or whatever is needed to remove it?

Oops,I see the location has already been answered...my bad.


Thanks,