Hello everyone!! I have a 2012 f150 4x4 scab xlt with a electronic locking diff. . I bought the truck 7 months ago and haven't had a chance to use the 4wd until this weekend. {we were blasted by a snow storm} I was on packed snow at an intersection and upon taking off ,I decided to just lock the rear diff.{no 4wd engaged} and see how well the eld worked.It grabbed well and left fine but the rear end made a "clunk,clunk,clunk" noise rather loud.It sounded to me like the clutches were locking and unlocking rapidly.I have read up on the eld and have found out it will disengage after 25mph.When this occurred,I did look at the speedo and I was only moving at 15 mph.Every time I tried it afterwords,it would do the same thing.Sooo, I went to my Ford dealer,showed him what it was doing,and they said this was "normal".I should also say that I had turned off the traction control before doing this.So what do you guys think,normal or not normal????

 

Welcome to FTE Dzull .

You posted in the incorrect forum, but no worries. I'll get the thread moved for you.

 

Dzull,

I haven't used my ELD much but the times I have I did not notice any clunking noises. I would be a little suspicious. Did you buy the truck new or used?

 

NOT normal. The e-locker physically locks both sides of the differential together for times when you need the traction. If it was designed to slip then it wouldn't be called a locker!

The only thing you should notice if yours is working right is some tire scrub when you turn. That's because it locks the rear wheels together which forces them to operate at the same speed. If you hear or feel anything other than tire scrubbing something is wrong.

 

2012 - F150 SCREW 3.55 ELD

I can duplicate the OP's results with the locking diff. i have not taken it to a Ford dealer yet as frankly i think it is normal.

What i believe it to be is drive line slack and the electronic limited slip causing the rear tires on one side to spin slower when it engages and then the brake releases it and the clunk is when the axle gets the slack removed.

To verify this I jacked the back of the truck up(make sure front wheel are chocked), try spinning one wheel with the diff open. i noticed when open, both wheels would respond almost instantly to change in direction. Then engage the ELD and try turning the wheels, you will notice they both turn in the same direction but if you change directions there was a little bit of play in the axle. This could account for enough that if the brake on one side applied and released it could cause the clunk we are feeling.

Even if the you turn traction control off, the 2 wheel spin control is always on. (Page 298 of owners manual).

Well got to go back to work. Just my 2cents.

Jon-

 

I ave that EXACT problem as well (both from truck and my dealer)

I don't think its normal, nor do i think it is part of the one wheel spin control..

IF they implement an electronic locking diff to allow full lock to rear axle, the one wheel spin control SHOULD be disabled, if not your literally smashing the clutches together upon each engagement of the spin control..Eventually the locker is going to fail, and may take more out with it...

Ive had many trucks with lockers (aftermarket) and when its locked in you know it, i also know that they do not like to be abused with intentional opposing stresses!! The tire spin control reacting when the locker is engaged is doing just that!!

 

I did buy the truck used {only 13,000 mi. on it } However, I don't believe the truck was abused it is in mint condition .It is strange how my dealer says it is "normal" though. I am planning on taking it to another dealer and get their opinion.

 

With so much experience with lockers you should know that they don't use clutches like a limited slip...

 

I have a 4x4lariat 2013 only tryed it once going straight on a gravel driveway about 15mph pulled it in not a sound took it out when I got to the blacktop??

 

Was having a brain fart. Could not remember terminology for a FULL OUT locking diff.

There are lockers with clutches and sprags, maybe do a bit of research before the sarcastic remarks come out.

Cheers👍

 

I don't think that's what is going on. If that were the case all trucks would exhibit the same shuddering that yours does. And mine most certainly does not. My driveway is a 1/4 mile long dirt path through the woods, and I've played with my locker in more than a few situations. I spin the wheels regularly playing around in the snow, and I've never heard or felt any kind of shudder.

I have, however, heard reports of people with defective lockers that don't lock up and make that kind of noise. It's not normal!

 

https://www.facebook.com/photo.php?v=10151777946877202

Here's a vid of my diff noise.... TCS and advance trac is shut off ( as far as it can go)... First little spin nothing happened, then a bit more throttle and the noise appears.. I can have this noise occurring all the way to 40km/hr if i want (just feathering throttle until locker automatically kicks out)

 

Yeaahhhh...that's NOT normal. Sounds to me like the locker mechanism is either broken or not engaging all the way.

 

I had my arm resting on the window sill and you can leterally see the shock going through the truck with the way the camera shakes...

Going to make a new Thread to see if I can get the Canadian reps on here to have a loos-see..

 

Take it to a different dealer.