Rearend/Susp truck noise and acceleration hesitation?

[FordFanStan]

I searched. Multiple sites. Still no clue.

Issue: On acceleration from stop, it feels like there is weight shift and hesitation, then a suspension creak/snubber type noise, then no more hesitation and momentum instantly increases. All happens within about 1-2 seconds probably. Best I can describe.

2010, 5.4 Scab, 53k miles currently.
First noticed on the truck probably about 30k miles.
Not ran off-road too hard or too often.
No shock leaks or issues ever.
Took to stealership 2 different times, they say no problems.
Took to stealership 3rd time around 35k, they replaced the shocks.
Noise was still there after, took back to stealership, they still insist no issues.


I took some video, but when uploading onto Youtube the quality was lost. Turn your volume up to hear.

Rear-end/Susp Noise 01 - YouTube

Rear-end/Susp Noise 02 - YouTube


Today:

• Looked at driveshaft because so many posts about greasing d-shaft when rearend noise; obviously those posts did not make sense. solid one piece alumi shaft with greaseless u-joints.
• Noticed transfer-case seal for d-shaft slip yoke has been leaking a little.
• Removed spare tire, tightened winch, etc. Still has issue
• Frame harmonic absorber "tuned mass damper" bushings were rotted, removed from truck. Still has issue.
• Took c-clamp and tightened overload to double leafs, first in back, no change. then in front of axle, still no change. Still has issues.

I'm still leaning towards axle wrap just because of the feeling. I don't think it would be a rearend issue because I don't foresee an issue from the rear-end with this type of noise, but who knows.



Any experiences or ideas on how to help try to diagnose would be greatly appreciated.

Thanks, Stan

 

[pat'sRAPTOR]

did you take off the rear diff cover and look at the gears?

---------- Post added 01-26-2014 at 12:00 AM ---------- Previous post was 01-25-2014 at 11:57 PM ----------

in that second video look at your drive shaft it shifts up a lot more than any one i've seen watch it a few times and keep you eye right on the drive shaft you see most of it disappear when you accelorate. so your axle is moving or "wraping" a good amount. do you still have the stock leaf springs on there? have you checked the bushings on the leaf spring attachments? also check the U bolts holding the leafs down make sure those are tight

---------- Post added at 12:03 AM ---------- Previous post was at 12:00 AM ----------

from what you're describing it almost sounds like your leafs are gone.. that hesitation you feel is most likely the axle wrapping and once it stops it allows the truck to accelerate. kinda like its taking away that initial drive its getting and its making the axle turn and once it can't turn any more it accelerates normally.

 

[FordFanStan]

pat'sRaptor,

First, thanks for the reply.

1. I have not inspected the differentials or gears yet.
2. All stock suspension. Checked bushings, they nothing look cracked or missing. All u-bolts, shackle bolts, etc tight and no sigs of wear anywhere. When me and my buddy were trying to film this, we agreed the driveshaft and the pinion gear shaft area/front of diff housing moves up a lot.
3. This entire time I have always though it was axle wrap, but I've never had a buddy around to help film until recently so I could never be sure. I agree with your description of the feeling. When I clamped the spring, I would have thought it would have helped though, and it didn't appear to at all. I tried front and rear leafs clamped up to overloads:
   
   
   

Don't want to spend a lot on the Raptor right now so I guess I'll do a diff fluid change and inspection first. (Im at 54k almost, so it wouldn't hurt plus I could do a trans fluid and filter change too). Next I suppose I could band-aid this with traction bars, but let's face it, the springs are probably gone so I don't like the thought of that. Next cheapest would be to look for some used low mile stockers. Last scenario would be Deavers or Nationals I guess.

Thanks, Stan

 

[Hockster]

Odd sound... to me from a vid it could be the ebrake cable moving and causing the brake to hit. Not sure so hard from a short vid.
does it do it whit you holding the brake some too. try that see if the noise changes

 

[FordFanStan]

Hockster,

I don't get that type of feeling, but I will test with applying slight to moderate brake pdeal pressure today and then with slight parking brake as well. One buddy that heard it said maybe the caliper sticking too, but I just don't think so based on the feel when driving. I will check it out.

Thanks, Stan

 

[Hockster]

Hockster,

I don't get that type of feeling, but I will test with applying slight to moderate brake pdeal pressure today and then with slight parking brake as well. One buddy that heard it said maybe the caliper sticking too, but I just don't think so based on the feel when driving. I will check it out.

Thanks, Stan

Its that clicking that leads me to the brake

 

[pat'sRAPTOR]

could be the brakes sticking didn't even think of that! i have a 2010 with just over 68K and i replaced and flushed all the fluids around 45K and im getting ready to do it again at 70K right before TRR so it could be the brake fluid or maybe air in the line and not allowing the brake caliper to completely disengage till it gets rolling.

hock thats why you get paid the big bucks lol you think outside the box! plus you're a ford tech so that doesn't hurt

 

[FordFanStan]

Well I tried many different attempts with different brake pedal pressures as well as parking brake pressures and different acceleration techniques. No matter what I tried, the hesitation/weight shift feel and the susp noise did not disappear or even change.

Sounds like I should pull the diff cover and inspect, otherwise look for some springs.

 

[Bar]

Isn't that the sound of the driveshaft slip yoke? Tough to tell, but I recall my truck had the same noise before they replaced it under warranty.

 

[pat'sRAPTOR]

There was a tsb for the drive shaft clunk youmight wanns get it checked out have the dealership look it up they should be ableto find it or hock might be able to post it here for you