Ladies and gents,

2016 expedition owner here looking for some quick advice. I’ve got the 3.73 HD tow LSD and experiencing the well known issue with the clutch packs sticking. 40,000 miles on original fluids, from a stop (mostly after it sits overnight or after long drives) turn left or right and feels rumbly and I can bear the noise from the rear. Going to be doing a rear diff fluid change myself since local dealer wants $200. I’ve done some research on other forums and it seems amsoil severe get 75w90 is a go to. Would like anyone’s opinion that has changed there’s and what you decided to use. I will also be adding ford xl-3 friction modifier. Thanks to everyone, jut trying to see what my best fluids will be for this truck

2016 expedition el platinum 4x4 3.73 LSD
5 star 93 perf v7 tuned
*i do not tow as of now with the truck*

 

Can’t go wrong with amsoil severe gear. Since it is a limited slip, it will indeed need a friction modifier. You can use Ford xl-3, but amsoil have their own called slip lock, especially formulated for LSD using their gear oil.

 

I don't think that what you're describing is a "well-known" problem of sticking clutch packs. Sticking LSD's are usually from a lack of friction modifier, usually right after changing fluid or installing an LSD. And the sticking is usually a banging, as they let go and grab again. Not a rumbling.

"Rumbly" noise from parts that have bearings is usually worn bearings.

At 40,000 miles you shouldn't be having any diff problems or need to change the fluid unless you've have had it underwater. Might be misdiagnosing the cause of the noise.

 

Still under warranty ? I would use Ford fluids.

 

I had the same problem in my 2002 f 150 I changed fluids and added friction modifier and it cleared up.

 

Thanks @BareBonesXL what I plan on doing is taking the front tires off and really giving the suspension a good once over, gonna take the calipers off and check the pads and rotors see if maybe one is sticking. I’ve checked the 4x4 vacuum system and last year had the check valve and solenoid against the firewall replaced and they gave me two new actuator assemblies (HL1Z- 3C247 A) 15,000 miles ago when I had the grinding sound which they diagnosed as the 4x4 system trying to engage due to faulty check valve. Print out from technician stated they tested vacuum, replaced the actuators, greased the hub bearings and put everything back together.

Now im leveled with 35s so not sure if maybe the suspension angle is messing with anything but it’s just weird that it is only noticeable when turning left or right from a stop or after the truck sits overnight.

 

I just finished changing all the lubricants in all the gear boxes for my 150,000 service. In my rear diff, I used Motorcraft premium 70W90 synthetic gear oil. In the front gear box I used Motorcraft Premium 70W140 Gear oil. XL-12 went in the transfer case.

 

Also here is a short clip of the noise I’m hearing that goes along with the rumble/ vibration/ chatter whatever you want to call it. Definitely sounds like coming from rear. What do you all think.

Sound up, noise starts around 4 secs in

 

A tech told me on my 2010 f150 lariat, to go to an empty parking lot, and make like a dozen sharp left turns, and a dozen sharp right turns, at a fairly quick pace, after installing "2" bottles of friction modifier, that it might eliminate the "rumbling noise" (sounded like I was running over rumble strips). It worked.

I drove the truck for 2.5 more years, and never heard the noise again.

Was told the clutch packs were stuck together. Whether or not it was a fluke or not, I can't say. I do know the noise/feel went away, and THAT was all I did.

 

Deleted. duplicate post.