This make sense??

[Tom7227]

2005 F150 that is 'stuttering' when making a left turn. 95 K on it. Friend's rig - the mechanic told him that the oil in the differential is worn out and that it needs to be replaced or an additive put in. 4WD. I'm sure the fluids - differential and trani need servicing but I don't know enough about differential's to know if this fluid idea makes sense.

Thanks for the advice.

Tom

[Scott K]

These trucks have a limited slip diff in them, and they have clutches in the rear diff to allow slipping on turns, what you are more then likely feeling is the clutches chattering, and this is very comon for this truck. The correct fix for this would be to replace the clutches inside the rear diff, and install new fluid and additive to the rear diff.

But what I would do before this, if the truck was mine, I would try adding a bottle of friction modifier to the rear diff before spending the money to put the new clutches in it.

[Shack]

Yep, the first step in freeing up the clutch disks/plates is to add the friction modifier additive, drive for about 100 miles and see if it goes away. If it does not, then try a full fluid change with the additive. Then worst case if an O/H of the carrier.

9/10 out of ten just putting the additive in will fix it, but it is a good idea to change the fluid, but it is not cheap.

Good luck!

[Jeremy airjer W]

I haven't had a fluid change fix one yet but I have never had new clutches not fix it!

[Scott K]

I haven't had a fluid change fix one yet but I have never had new clutches not fix it!

This has been my experience as well!

[Shack]

This I have seen work and more than twice Not a guarantee, but the majority of people who tried it had a good result. 4WE can check, but I swear this was a service bulletin/procedure to try first right from Ford.

[Shack]

I haven't had a fluid change fix one yet but I have never had new clutches not fix it!

Did you forget to put the additive in?

That is almost a guarantee in it’s self it will happen and for surely not fix it. Most times this was the case when trying to cure this. The customer or someone did a fluid service and did not put the additive back in.

[Scott K]

The only bulletin I know of is the ones to replace the clutch pack assy. and add the friction modifier. I just checked, and didnt see any ssm's or tsb's like that.

There was an internal bulletin from Ford to add some friction modifier to the auto transfer cases for chattering, but later found out the auto 4wd clutches did quit chattering, but the clutches wouldnt last long with the additive in it.

[Shack]

There was an internal bulletin from Ford to add some friction modifier to the auto transfer cases for chattering, but later found out the auto 4wd clutches did quit chattering, but the clutches wouldnt last long with the additive in it.

I recall that one!