Symptoms:

Under power (pulling out of a parking lot), making low speed maneuvers
Wheels have to be turned left or right (at least 30-40%)
Will not replicate if wheels are aimed straight
No noises, grinding, or squealing

If all of these criteria are met, I get a relatively heavy vibration. Like I said, it will not do it when the wheels are aimed straight and will no do it if throttle isn't applied.

Any ideas? I have done research on the IWE, the hubs, the actuators, etc, but I do not have any grinding or loud noises.

Thanks!

 

clutch packs are sticking. common problem. just live with it.

 

Sounds like the friction modifier in the rear end gear oil has broken down.

 

If it's from the rear, probably the clutch packs in the LS as stated, and not a problem. If from the front, a wheel bearing.

 

wouldnt it be a front end issue since its dependent on the wheels being turned?

is there anything at all that can be done about the LS, like changing the fluids and adding friction mod to it?

 

no, if it is the LS, it's just doing what itis supposed to do. That is the one time your rear wheels are turning at different rates and the clutches are trying to lock up. To get traction. They are confused.

 

oh sweet.

so then general consensus is to just ignore it, not a big deal? If that's the case, I guess I can do that. I read a TSB saying to replace the clutch packs if needed, so i guess I'll try to research that process and parts cost. Anyone info on that?

Thanks for the help guys, you really alleviated some unnecessary stressing.

 

mine have been doin it for the last 20,000 miles. i changed the fluid and it quit for a bit but is back. I'm not to worried about it though.

 

You can also change the fluid and make sure the friction modifier is added. That fixed the problem on my 04. Ford also changed the spec for the fluid. It used to be 75w90, Now the spec is 75w140.

 

Do some figure 8s to clean the clutches then change the fluid. Don't forget to add friction modifier.

 

just because im leazy, can someone steer me to a how-to on the diff service? =)

 

Correct me if I am wrong. If the 4x4 lost all the vacuum pressure and engaged as it should, bambo wouldn't know if it was in 4x4 and would would in fact have these exact symptoms.

Or would the 4x4 engage light be on or check engine light alerting to a problem?

I'd find a gravel road, stick my head out the window and punch the gas watching for the front tires to spin.

 

https://www.f150online.com/forums/20...lots-pics.html This has all the info you need to change the rear diff fluid.

 

like stated above this is a temp fix the clutches are already burnt and need changing if you got a 9 3/4 rear end it takes a special tool to collaspe the spring washers to remove the spider gears but someone may have a way to remove them without it i used the tools since i have them makes it alot easier