2004 Rear Trailing Arm Issue? New member a little help please.

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TheRoosterMMA

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Hey guys,

New member from Florida. I am a Mustang guy for may years, but relatively new to the expedition. Recently I heard something snap in my rear end and then followed by drive shaft noise. the noise would go away if I accelerated slowly. When I jacked it up, I assumed (based on a youtube video I watched which has similar symptoms) that the Differential bracket isolator (bushing) had failed. the drive shaft yoke and u joints were rubbing on the rear sway bar. I was able to acquire a new isolator. Ford did not have one for my year and told me that the later year isolator would not fit. As it turns out they were incorrect. I removed the bracket and pressed in the new isolator. To my surprise, the problem was not fixed. I came across a post on here which said the 2003 and 2005-2006 models had an issue where the rear trailing arms broke which caused the rear end to tilt. The bulletin said this would cause the drive shaft to rub on the frame above it and cause damage. I noticed this damage today when I was under it again.

Here are my questions which I very much would appreciate advice from someone with experience:

1) It appears as if the 2003 model had a different set of trailing arms for both upper and lower. From what i can search, the upper trailing arm for 2004 is completely different. The truck makes a huge clunk when going into drive. is this from a failed trailing arm?

2) Can someone point me in the right direction toward an exploded view of the 2004 rear end so I can get a better grasp on what is going on? My mustang rear suspension is two upper and two lower control arms. I am not at all familiar with how the expedition suspension is set up and or functions. are there one or two upper trailing arms?

3) If it is in fact a trailing arm, what is the best way to go about replacing it? Where can I get a replacement.

Thanks in advance for any help. I spend a fair amount of time on the mustang boards helping others with their issues. Hopefully I can get the same here.
 

whtbronco

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To me it sounds like you're describing a Gen 1(97-2002) Expedition that had a solid rear axle and trailing arms. The Gen 2 (2003-2006) is independent rear suspension. Though you noted that you replaced the torque arm bushing for the rear diff which, I am actually dealing with now as well on my 2004.

Anyway, the IRS has upper and lower control arms, control arms, spindle and more or less a tie rod. It's a lot like the front suspension. You could have a shot bushing in the control arm or spindle, I'd be looking at the CV axles though.

I suggest your best bet is to get it up on jackstands, have someone you trust shift between reverse and drive while you are under it and look for the movement. If it's a loud clunk you should see whatever it is move.

Rear suspension bushings and control arms are getting scarce, FYI. I don't think there are any good quality ones available.
 
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TheRoosterMMA

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To me it sounds like you're describing a Gen 1(97-2002) Expedition that had a solid rear axle and trailing arms. The Gen 2 (2003-2006) is independent rear suspension. Though you noted that you replaced the torque arm bushing for the rear diff which, I am actually dealing with now as well on my 2004.

Anyway, the IRS has upper and lower control arms, control arms, spindle and more or less a tie rod. It's a lot like the front suspension. You could have a shot bushing in the control arm or spindle, I'd be looking at the CV axles though.

I suggest your best bet is to get it up on jack stands, have someone you trust shift between reverse and drive while you are under it and look for the movement. If it's a loud clunk you should see whatever it is move.

Rear suspension bushings and control arms are getting scarce, FYI. I don't think there are any good quality ones available.
The bushing I replaced is for the bracket that holds the differential to the frame. I do not think it is called a torque arm though. Ford refers to it as the differential bracket. it is a large almost triangular metal piece that bolts directly to the side of the diff. is that what you are referring to as the torque arm? the vehicle is a 2004. it appears as if the diff is tilting which has caused the drive shaft to rub up on the frame and or at times causes the drive shaft to hit the rear sway bar. this is exactly the symptom that was shown in the bulletin for 2003 and some 2005-2006 models. I am going to put it up on stands today.
 

whtbronco

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I've seen the bracket identified as support bracket, differential bracket and torque arm. Torque arm is what it's identified as in AllData. I believe we are referring to the same piece, screenshot below. I'm replacing mine tomorrow evening.

It'll be interesting to see what you find, but you must have some significant movement from the sounds of it. Mine is a 2004 as well, but the 2003-2006 have the same rear suspension. The only difference I know of is that some had air springs and some had coil springs. Still very little difference aside from the air suspension system which I have disconnected and replaced with coil springs.

1714093584501.png
 
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TheRoosterMMA

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I've seen the bracket identified as support bracket, differential bracket and torque arm. Torque arm is what it's identified as in AllData. I believe we are referring to the same piece, screenshot below. I'm replacing mine tomorrow evening.

It'll be interesting to see what you find, but you must have some significant movement from the sounds of it. Mine is a 2004 as well, but the 2003-2006 have the same rear suspension. The only difference I know of is that some had air springs and some had coil springs. Still very little difference aside from the air suspension system which I have disconnected and replaced with coil springs.

View attachment 80906
yes same thing. fyi the later isolator . bushing will work for 04 model. I found the issue though. both of the rear bushing that hold the diff onto the frame were gone. made diff slip forward and changed angle. it is exactly what I posted earlier from the post I found. the post said it only applied to certain 03's and 05-06 not so. it also applies to 04. I found the "insulators" as ford calls them at a dealership in tennesee for 35 each.
 
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