Hissing/Whining Noise after Susp. mods

[spitin venom]

I installed Eibach pro kit springs, BMR adj. LCA's whith one polly end and one rod end, and a MM adj. panhard bar with rod ends. I am now getting a hissing/whining noise from the rear end. I think I adjusted the correct pinion angle to -2.5* (driveshaft is -4.5 and the pinion read +2 on my digital angle finder). I have read that it is normal to get more NVH but I just wanted to see if anyone else has the same problem. The noise doesn't really bother me but I just wanted to make sure I didn't mess anything up and that I calculated the pinion angle correct. The rearend does not clunk or rattle and the car looks a million times better! I noticed that the stock panhard is filled with sand and has large rubber bushings to kill NVH. I am guessing that the rod ends on the MM panhard bar is what is projecting the noise into the cabin. Your wisdom is appreciated.

 

[Tob]

I run the same panhard without issue.

You stated you can adjust the pinion angle - so what arm are you using there? I've noted that you'll pick up gear noise through the upper and into the cabin from a solid bushing there. Do you have rod ends or poly there?

 

[GT500RedStripe]

Did this apply?
DS is negative if it slopes downward toward the rear end.
Rear is a negative if it slopes downward toward the front of the car.
Did you measure under load?

 

[spitin venom]

I run the same panhard without issue.

You stated you can adjust the pinion angle - so what arm are you using there? I've noted that you'll pick up gear noise through the upper and into the cabin from a solid bushing there. Do you have rod ends or poly there?

I am using the fatory UCA and the BMR TCA021 adjustable LCA's. They have a poly bushing on one end and a rod end on the other. In my research I came across this website cherod.com/mustang - LCAs that was pretty informative and helped guide me. The jam nuts on the MM adjustable panhard bar were on super tight. It took two of us to get them loose which caused the panhard bar to get chewed up. It is just cosmetic scuffs so it is no big deal. It was also a pain in the ass to adjust. I might get the BMR one in the future with the aduster/jam nuts in the middle of the bar which would have made my life a hell of a lot easier during the install.

Did this apply?
DS is negative if it slopes downward toward the rear end.
Rear is a negative if it slopes downward toward the front of the car.
Did you measure under load?

DS is negative -4.5*. The pinion flange is +2*. Half the websites I visited said this was correct and the other said it is wrong. The suspension was loaded. If you look at the picture of the DS assembly on this website cherod.com/mustang - LCAs mine looks to be adjusted similar to the illustration. I hear gear whine from the rearend and hissing from road noise. It isn't very loud but it is noticeable. I don't drive the car often but I just want to make sure that I am not hurting anything.

 

[Tob]

The jam nuts on the MM adjustable panhard bar were on super tight. It took two of us to get them loose which caused the panhard bar to get chewed up.

The MM bar has flats on it so that you can prevent it from rotating while you try to loosen/tighten the jam nut.

Were you trying to use a pipe wrench or did you put it into a vice?

It was also a pain in the ass to adjust. I might get the BMR one in the future with the aduster/jam nuts in the middle of the bar which would have made my life a hell of a lot easier during the install.

I concede, having the adjuster located not far from the middle of the bar makes it easy to adjust. However, it is far from the best location from a strength perspective. In simple tension/compression using mild force, the bar should be fine. The higher the loading, say in compression, the more likely the inherent weakness from placing the adjuster at that point may present itself.

There should never be a load perpendicular to the 'normal' panhard plane, if you will. If there was, you'd eventually see it yield at the adjuster. If you supported each and of the bar in the air and tried to hang from it, again, it would likely yield at the adjuster. Note that the 'effective' diameter of the bar shrinks to that of the thread diameter at the adjuster. In general, a continuous bar doesn't suffer the same fate, although it would eventually yield as well given increased perpendicular loads.

Much better to have any threads at the ends of the bar. But as you found out for yourself, it means you have to lower the bar from the chassis bracket to do so. It is simple really as all you have to do is to slip in the bolts, nut one, but leave the other bolt without a nut on it. Verify the adjustment you need, slip the bolt out, adjust the rod end and slip it and the bolt back into place. You'll only have to do this once (unless you change ride height again).

The MM bar is also constructed from large diameter aluminum tube. Lighter than the stock steel tube as well as many other aftermarket offerings which are made from steel.

 

[spitin venom]

MM panhard bar is a very nice product. I have used some of their other parts on my '04 Cobra without any issues. They make very high quality stuff. What else could cause the rear end whining?

 

[Tob]

To start, good to hear that the car doesn't clink or rattle. When does the car hiss? Under load, coasting, cruising, etc? Is it worse at different speeds?

Also, are your gears stock?

 

[kent1]

The hissing sound could be the clutch which is the snake! :banana:

 

[spitin venom]

To start, good to hear that the car doesn't clink or rattle. When does the car hiss? Under load, coasting, cruising, etc? Is it worse at different speeds?

Also, are your gears stock?

The gear whine and hissing get a little more audible with speed. I start to notice it around 15mph. It makes the noise when I am coasting, cruising, decelerating, pretty much all the time.

 

[cluscher]

I think this is just the increased NVH you experience with those types of mods. After I installed my Griggs LCAs (heim on one end and bushing on the other) and adj panhard bar I also got a "hiss" for lack of a better term. Like you say, nothing major, just different then it was before. Nothing was wrong with the install, although that was my first thought as well.

 

[DaFreak]

I think this is just the increased NVH you experience with those types of mods. After I installed my Griggs LCAs (heim on one end and bushing on the other) and adj panhard bar I also got a "hiss" for lack of a better term. Like you say, nothing major, just different then it was before. Nothing was wrong with the install, although that was my first thought as well.

I agree with this. I'm running a very similar setup as Tob (see sig) and after the MM LCA's I heard the exact same noise (I call it a whirl) . I even took mine to have it looked at by master tech buddy at the dealership and he said the same thing. I've since forgotten about it. I will say one thing that did seam to quite things back down again was the install of the DSS aluminum drive shaft. Should of done that long ago.