loud bang from suspension?
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Member
Joined: Nov 1999
Posts: 70
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From: Raleigh, NC, USA
loud bang from suspension?
With 3000 miles on the clock of my '03 screw, all is going well with one annoying exception. There is a semi-repeatable loud bang from the suspension that hits so hard that it feels like the dash is going to fall out. It almost feels like you've been rear-ended. Anyway, I don't dare take this thing to any dealer yet... because of the circumstances to get the bang to occur. If I pull away from a stoplight hard in the rain- normally the tires will break loose when you go across the paint stripe, but when they grip again - BANG! The other way I've gotten this to occur is if I'm in a fairly hard left turn accelerating hard in 1st gear (held in 1st manually with the gear selector), then once you make the shift to 2nd gear - BANG! You've got to still be in the turn. After ****ing with cars for years, it feels to me like the driveshaft is bottoming in the transmission. None of the other F150s I've owned have done this - '97, '98 or the '01.
It is NOT the "tranny thunk" problem - I felt that problem in another f150 I test drove - it was more like the tranny was searching for the right gear, then slammed back into 1st.
The only other evidence to consider is the leaf springs have obviously changed from my '01 to the '03. At a minimum, the new springs have different isolators - they are white, possibly a urethane material. This is why I think it's a suspension-related problem...
I'm going to fabricate some spring clamps and see if the problem goes away. I had to make some spring clamps for my '98 since it had bad wheel hop problems in the rain... they fixed that prob, so maybe they'll work here.
Anyway, enough rambling... I'd be curious to hear if anyone else with an '03 has felt this BANG. You'd know it if it did it!
jC.
It is NOT the "tranny thunk" problem - I felt that problem in another f150 I test drove - it was more like the tranny was searching for the right gear, then slammed back into 1st.
The only other evidence to consider is the leaf springs have obviously changed from my '01 to the '03. At a minimum, the new springs have different isolators - they are white, possibly a urethane material. This is why I think it's a suspension-related problem...
I'm going to fabricate some spring clamps and see if the problem goes away. I had to make some spring clamps for my '98 since it had bad wheel hop problems in the rain... they fixed that prob, so maybe they'll work here.
Anyway, enough rambling... I'd be curious to hear if anyone else with an '03 has felt this BANG. You'd know it if it did it!
jC.
Senior Member
Joined: Aug 2001
Posts: 1,609
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From: Summerville, SC Near Historic Charleston
JC,
At what speed does this bang occur? Does it happen when you're rolling and accelerate? Mine does this too if I'm going between 20 and 25 mph and I accelerate and it drops down from third to second and bang, it hits hard. Now, if I'm going around 25 mph in a turn like in a subdivision, I can slow down like to 18-20 mph and then accelerate and no problem because the computer has already commanded the tranny to drop down to second with no throttle input and I can't detect when it changes from third to second. Just wondering...
~DM~
At what speed does this bang occur? Does it happen when you're rolling and accelerate? Mine does this too if I'm going between 20 and 25 mph and I accelerate and it drops down from third to second and bang, it hits hard. Now, if I'm going around 25 mph in a turn like in a subdivision, I can slow down like to 18-20 mph and then accelerate and no problem because the computer has already commanded the tranny to drop down to second with no throttle input and I can't detect when it changes from third to second. Just wondering...
~DM~
Senior Member
Joined: May 2002
Posts: 140
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From: Ocean County,NJ
Axle wrap?
Sounds to me that you have axle wrap. Mine does it so bad that it feels like the transfer case is coming through the floor. Only difference is mine has a 6" suspension lift. I am trying a ladder bar setup from Fabtech to try and fix this.
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Member
Joined: Nov 1999
Posts: 70
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From: Raleigh, NC, USA
Daveman: on wet pavement the bang occurs at very low speed - probably 5-10mph. When it occurs in a turn, it's at WOT on the 1-2 shift, whatever speed that is. Superbeast54: yes, axle wrap is exactly what my theory is... just didn't say it so succinctly. 
Spring clamps on the front part of the multi-leaf stack should help. I'll try it and see.
jC.
Spring clamps on the front part of the multi-leaf stack should help. I'll try it and see.jC.
Junior Member
Joined: Oct 2002
Posts: 8
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From: Wichita Falls, TX
Doubt this may help, but in my '01 Screw I used to notice a noise coming from my rear suspension too only when making a sharp turn. Turns out that my pass rear shackle bolt likes to loosen up. I took it out, and installed some thread locker and tightened it down. Noise was gone, I was praying my limeted slip wasn't about to blow.