i have a question for all the gurus here. i have a '06 4x4. in the last couple weeks i've noticed a popping noise from the front end only when in reverse and only for the first 5 or 6 feet. if i stop then go back some more, it doesn't do it. there is no vibrations while driving forward or reverse. i have checked all the bolts(lift kit installed), the cv joints are good, ball joints good. i have searched with no result. the thing i'm curious about is, when it is in 2wd, the front drive shaft is spinning. from what i have read, that is not supposed to happen. could the problem be that my front diff is stuck in the locked position? and how do i go about fixing this? thanks in advance.

 

could it be a sway bar end link popping out? well popping makes me think of cv's, but i dont let know

 

X2 This would be my first guess. Check where the swaybar connects to the LCA. Then i would check CVs and Ujoints. Does it make any popping noises when you're going over speed bumps or anything like that?

 

i've checked all the above to no avail. they all check good. no noise over speed bumps, only a slight pop when slow full lock turning from a dead stop moving forward. i have jacked up the front end and spun the tires with my hands and there is no noise. seems like it only happens when there is weight on the suspension.

 

I've had popping noises since my install and have tracked two of the sources of mine... One was the shocks topping out, which doesn't sound like your case (unless you have a leveling kit in there with your superlift).

The other though turned out to be the rear passenger side lower control arm mount. Seems the pocket that the control arm goes into is slightly wider than the control arm itself. So the result is when you tighten it down, it's got a gap on the backside so it lets it the control arm slip a little when there is force put on it.

I now have it WAY overtorqued (180 ft lbs) to try and get that gap closed as much as possible until Fabtech comes up with a fix. Looks like I may have to replace the rear crossmember completely. Really looking forward to that!

Anyway... Just make sure your lower control arm connections are "flush" and have even clamping on them. If the are slightly off, you can be torqued to spec and still have popping/slipping going on.

 

that sounds like what i might have, i've torqued the mess out all the bolts, but there still does seem to be a slight gap. do you think i could put some big washers in there like a shim to fill the space? maybe coat it with some graphite lube to keep the metal on metal squeaking down?

no leveling kit on mine, but your suggestion sounds spot on. my main concern is the wheel falling off or some major part coming off while i'm driving down the road. thanks for the reply.

 

I've been thinking about spacers... they would have to be very thin and heat treated. Maybe a structural washer?

But I'm kind of waiting to see what Fabtech comes back with on mine first though.

I definitely would not lube them. That would possibly make them slip more. You don't want any movement at all in that area.

And make sure you are using a torque wrench to tighten them. You may think you have them clamped down, but it is kind of hard to get 150 ft lbs on those bolts laying under a truck unless it's up on some kind of lift.

You may have already done all that... it's just me thinking out loud.

While I was typing this, it got me to thinking... I'm going by fabtech's torque spec at 150 ft lbs. So I did a little looking around and I've seen as high as 222 ft lbs as the spec for the lower control arm bolts. That would surely clamp them down flush!

I'm going to look around some more and see if I can find any info on Ford's torque specs.

 

Accordong to this post from Klassic a while back... It looks like 222.





Cut and paste. If there is a wrong value it is a Ford misprint.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Torque Specifications Description Nm lb-ft
Wheel nuts 204 150

Front Suspension
Wheel hub-to-wheel knuckle bolts 200 148
Tie-rod end nut 150 111
Front axle-to-wheel hub nut (4x4) 27 20
Upper ball joint nut 115 85
Upper arm-to-frame nuts 150 111
Lower ball joint nut 150 111
Lower arm-to-frame bolt and nut 300 222
Shock absorber upper mounting
plate-to-frame nuts (M10) 48 35
Shock absorber-to-lower arm
bolt and nut (M20) 475 351
Stabilizer bar bracket-to-frame bolts 48 35
Stabilizer bar-to-link nut 133 98
Stabilizer bar-to-link to
lower control arm nut 90 66
Anti-lock brake sensor bolt 18 13
Caliper anchor plate-to-wheel
knuckle bolts 200 148
Caliper-to-anchor plate bolts 32 24
__________________
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https://www.f150online.com/galleries/....cfm?gnum=3831

 

when me and my dad installed the lift, we had it on a frame lift and torqued the lower control arm bolts to a little over 150, cant remember the exact number, but we were going off the installation instructions. but those numbers you just posted do offer some valueable information. i'll have to get under there again and torque them some more. thanks again. at least i know i'm not the only one with this problem and can ride on it for a little bit with out major damage...just an annoying popping sound when backing up.