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Hey All,

So I've got a 1999 3.8l Mustang(obv.), 5 speed. The car has been great so far, but I cant seem to get rid of that rocking/heaving from a stop. I want to say its the U-Joints, but from the video, I'm not so sure. Could be the part where the transmission connects to the shorty driveshaft just before the U-Joint connects to the main driveshaft. (if that made sense) Could be the U-Joints at the diff???

My car also make a noise like, "wrreown, wrreown, wrreown," when backing up. It gets louder as I speed up in reverse. I can also hear a slight grinding/grating from underneath the car when I step on it without downshifting, or accelerating up a hill at low revs (particularily in 4th.) I also occassionally hear a ticking coming from underneath the the car between 1500 and 2000RPM. Depending on how smooth my launches/shifts are, and if Ive been over revving a just little too much, while letting the clutch out slowly to wait for the ******* in front of me to move, the noise becomes more or less pronounced accordingly.

I had a Spec Stage One Clutch and Spec Stage One Flywheel installed about a year ago, because I thought that the flywheel may have been the problem. I threw the new clutch in there, cause I figured, why not while Im already in there, right? My mechanic also took my transmission apart, and replaced all the bearings in there too. So I dont think any of those are the culprit.

I got under the car today for the first time in 6 months, and I took the following video. And I know that in the video, I repeat myself and some of the information that I've stated here. In my defense, I was probably just a little stoned from when I was cleaning the car earlier. :blink:

Anyways, thanks a lot in advance guys!

http://youtu.be/rbh5FJAzzrk
 

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My 2000 has a little movement in the same area. As for the vibration when taking off. . . I replaced all the bushings in the rear suspension and my vibration went away during take off. Reverse will sound louder than forward. . . forward gears are heilical (slightly spiral cut) and reverse is not (straight cut). The helical are quieter and force the gears to stay meshed when in motion (no popping out of gear).

I would be curious to see what others say about that play, though from your video
 

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My 2000 has a little movement in the same area. As for the vibration when taking off. . . I replaced all the bushings in the rear suspension and my vibration went away during take off. Reverse will sound louder than forward. . . forward gears are heilical (slightly spiral cut) and reverse is not (straight cut). The helical are quieter and force the gears to stay meshed when in motion (no popping out of gear).

I would be curious to see what others say about that play, though from your video
Hm. It never occurred to me that it might be the play in the rear suspension bushings causing the rough "launches". I thought of almost every other scenario (Engine/tranny mounts going, play in U-joints, warped flywheel, play in rear diff, etc.). Maybe instead of driving onto my ramps, I need to get her up on some jacks to check out how much play there is in the suspension bushings.

As for reverse, It's good to learn that reverse has straight teeth. Never would've guessed. However, the "wrreown" noise I was referring to is definately out of the ordinary. It's something that they would have addressed at the factory if it were caused by the straight teeth. And I am sort of familiar with the sound of the straight cut gears too. Despite how much louder straight gearing tends to be, I probably couldnt hear it over the much louder, "wrreown, wrreown, wrrown" anyways. Not sure though. I'll try to get videos of the sounds it makes reversing, and the gratting I hear when accelerating in 4th at low revs.

In any case, you've been very helpful in the meantime. Thank you!:bigthumbsup

Any and all suggestions still welcome.
 

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I replaced my rear suspension bushings with upper and lower tube suspension arms with bushings already installed. It only cost me about $180, plus I put on new spring insulators since I had them out anyway.

If you have a conv stang, a strut tower brace also helps to keep out some of the shakes.
 

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Discussion Starter #5
I replaced my rear suspension bushings with upper and lower tube suspension arms with bushings already installed. It only cost me about $180, plus I put on new spring insulators since I had them out anyway.

If you have a conv stang, a strut tower brace also helps to keep out some of the shakes.
That's a great suggestion. Thanks again! BTW, I still havent gotten my car up on jacks yet to check out the play in the rear control arm bushings. I was also thinking about putting in the rear (and front) strut tower braces, even though mines a coupe. I heard that when cornering at the limits, our stock chassis' will flex so much that the passenger and drivers headrest can move as much as 1 whole inch from their rested position. (Yikes!)

BTW, I took and posted another video. This time it's of me reversing. You can hear the "Wrreown" sound I spoke of earlier. Here's the link:

http://youtu.be/q5YZQYs8tPI

Thanks Again!
 

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The noise does sound excessive. I would have that looked at. My guess would be transmission since it only does it on reverse.

As far as vibration, I've been told by a person who use to work for a Ford dealership (at their alignment dept) says that side-to-side vibration (you can notice this when looking in your rear view mirror while driving) is rear suspension. It is typical for the mustangs. Bushings should take care of it. You can buy fancy, adjustable control arms and stuff OR you can get the simple upper and lower control arm kits for under $200. These already have the new bushings installed except for the upper arm-to-axle bushong. The bushing on the upper axle that connects to the upper arm I was unable to change, even with the special tool that is sold for this bushing. My 2000 rides smooth once I replaced everything. I also put on new coil spring isolators since the springs had to be removed anyway.
 

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Sounds like my 88 turbo volvo's transmission before it blew lool.

What sort of shifter style do these manuals use, external or internal linkage?

This turbobrick had external linkage, modified shifter which was coming loose due to idiot PO. It was contacting the driveshaft occasionally making that noise.

Sounds like a tranny noise, another car I had made that in reverse due to no syncro
 
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