Rear end clunking.
09-30-2009, 08:21 AM
#1
1st Gear Member
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Join Date: Sep 2008
Location: New Hampshire
Posts: 74
Rear end clunking.
HI. I recently installed J&M lower controll arms ever since than I get a lot of clunking from the rear end. It happens when I shift and also if i am slowing down and hit the accelerator to speed up. Any ides or reccomendations would be greatly appreciated.
I had my torque wrench calibrated recently so i know I got the right tourque on the bolts (129 ft/lb) and the suspension was loaded when the bolts where tightened.
I had my torque wrench calibrated recently so i know I got the right tourque on the bolts (129 ft/lb) and the suspension was loaded when the bolts where tightened.
09-30-2009, 08:42 AM
#2
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Join Date: Feb 2008
Location: NJ
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I and others have had this problem. No cure for it to my knowledge. I replaced the LCA bolts as recommended by steeda and it helped(I think?) but is still not like the stockers.
It's supposedly the stiff poly bushings that transmit the extra NVH. WHy it only happens to select few i wish I knew. But in my case with the clunking noise I've whipped the hell outta the car with the new LCAs for almost 2 years drag racing included and they're still fine.
It's supposedly the stiff poly bushings that transmit the extra NVH. WHy it only happens to select few i wish I knew. But in my case with the clunking noise I've whipped the hell outta the car with the new LCAs for almost 2 years drag racing included and they're still fine.
10-01-2009, 12:58 AM
#4
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Location: New Hampshire
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They are not adjustable and the car is stock ride height. I do have some play in the driveshaft but don't really know what the tolerance is. It also seems to get worse as the car warms up. I noticed that it even clunks as I move the shifter into reverse.
10-01-2009, 07:00 AM
#6
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Join Date: Jul 2007
Location: TX
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It clunks as you SHIFT into reverse with the clutch depressed or clunks when you let off the clutch and start MOVING in reverse? You had zero issues prior to the lca install correct?
Oh and which model JM ca's do you have? the race model (extreme joint) or poly type?
Oh and which model JM ca's do you have? the race model (extreme joint) or poly type?
Last edited by Rubrignitz; 10-01-2009 at 07:03 AM.
10-01-2009, 07:03 AM
#7
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Are they the "Extreme Joint" variety
http://www.americanmuscle.com/extrem...trol-arms.html
if so make sure the "extreme joint" side is on your axle not your body. Also, I would take off the extreme side and make sure the ball is good and tight, you should hardly be able to move it by hand. When you put it back together, make sure the joint is not twisted already, as that will cause bind.
Also, look at the ends VERY closely. One end should be a little fatter off to one side. There is a offset from the body mounts to the rear axle's. If the offsets are not in the right place, that will also make a ton of noise.
If there still making noise or are not extreme joint versions... I don't know man. Doesn't make sense that putting in a LCA that is fixed with polly bushings would add any noise by them self.
http://www.americanmuscle.com/extrem...trol-arms.html
if so make sure the "extreme joint" side is on your axle not your body. Also, I would take off the extreme side and make sure the ball is good and tight, you should hardly be able to move it by hand. When you put it back together, make sure the joint is not twisted already, as that will cause bind.
Also, look at the ends VERY closely. One end should be a little fatter off to one side. There is a offset from the body mounts to the rear axle's. If the offsets are not in the right place, that will also make a ton of noise.
If there still making noise or are not extreme joint versions... I don't know man. Doesn't make sense that putting in a LCA that is fixed with polly bushings would add any noise by them self.
10-01-2009, 07:23 AM
#8
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10-01-2009, 07:52 AM
#9
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Join Date: Sep 2008
Location: New Hampshire
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When I depress the clutch and move the shifter into rewerse just as it slips into reverse it gives of a clunk it will also clunk as I shift trough the gears and as the clutch engages. I really cant explain it. The only thing I can think of is thet the condition was always present and thet the poly bushings are just transmitting the noise better than the stockers. And the arms are just the regular J&M poly bushing.
10-01-2009, 10:52 AM
#10
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What I was aiming at with my clutch depressed/moving question is figuring out whether it's driveline slop or shifter linkage issues. Now you're saying it was present to a lesser degree PRIOR to the lca install so maybe you're just hypersensitive to your shifter linkage noises. Mine clunks too when I put it in gear but the MGW has a heavy, positive, quality feeling engagement clunk and I look at that as a good thing. You may not. It's a mustang not a bmw so it's not going to work like a quality rifle bolt, although the MGW is the closest I've come to that feel 
.
I thought JDWalton was really on to something with the orientation of the lca's but since you have the poly's (which also have a large/small side for inside/ouside orientation by the way) that may not be the issue. I had clunking issues after lowering the car and doing upper/lower lca's all at the same time and was able to adjust the upper LCA to correct the pinion angle and it's smooth now. My one-piece driveshaft also played into that and everything had to line up perfectly to get rid of the driveline slop.
I'm kinda out of ideas for you at this point.
.I thought JDWalton was really on to something with the orientation of the lca's but since you have the poly's (which also have a large/small side for inside/ouside orientation by the way) that may not be the issue. I had clunking issues after lowering the car and doing upper/lower lca's all at the same time and was able to adjust the upper LCA to correct the pinion angle and it's smooth now. My one-piece driveshaft also played into that and everything had to line up perfectly to get rid of the driveline slop.
I'm kinda out of ideas for you at this point.