Did I get a bad example????

[cobralvr01]

So I purchased a 1997 Cobra back in January. It had several problems but I figured that these issues would be resolved with the parts I planned on replacing.
Problems it had:

• Vibration and humming in the rear end - The vibration happened when decelerating from 40+ and became more pronounced with the AC on or if decelerating in nuetral.
• Drive train noise - It had a lot of excessive drivetrain noise when driving around at low speeds (below 30mph).
• Suspension felt like crap - the suspension make excessive noise when going over bumps and rode like I was on marshmallows.
• Brakes "chattered" when rolling over small bumps - This was extremely noticeable on road that had a lot of very small bumps in the road.
• A whining noise when the AC was on and the clutch would be engaged.
• I could hear what sound like bad bearing (no chattering) in the transmission. I figured this was because of an unbalanced flywheel from the previous owner.

[*]Clunking when changing gears - There was a noticeable clunking noise when changing gears. Especially when at a stop.
Here's the things I have replaced on the Cobra since purchasing:

• New suspension bushings all around. Car feels very tight but seems to be too responsive and somewhat unsafe. When I turn it barely needs any movement from the steering wheel and it will jump over to the next lane.
• New transmission fluid - this made the sound in my transmission even louder somehow. I used Ford Mercon 5 as indicated.
• Replaced all shocks with Koni Yellow Adjustables - this seemed to produce more interior vibration noises and it's driving me insane.
• Rebuilt rear end - there's a bad vibration at high speeds when I have the gas just on the line where there will be load on the drivetrain.
• Replaced the UCA & LCA's with SVE CA's. Now, when I turn into my neighborhood that has an incline, my rear end make a loud pop sound. Almost as if everything is bound up in the rear end.
• Replaced DS with a Ford Racing Aluminum Driveshaft. I thought this would relieve alot of the drivetrain noises due to bad u-joints but it has actually made them worse. When driving around I feel like I have excessive backlash in the entire drivetrain. I have already reopened the rear and reset the backlash. The clunking when changing gears is still present.

So after all of this, the car still sounds like either the supsension or the drivetrain is just going to fall out. Did I get a bad example of an sn95 cobra or is excessive interior and drivetrain noises to be expected? I ask because I had a '98 cobra with about 32k miles and I don't remember it having anywhere near as much creaking, popping, and rattling.

 

[GRUSE]

Well what you are describing is a mechanical soup,a lot of different ingredients combined to make a unpleasant driving experience.

Lets combine the similar pieces of the drive train puzzle. A)Vibration and humming in the rear end,B)excessive drivetrain noise when driving around at low speeds,C)bad bearing (no chattering) in the transmission,D)possibility of unbalanced flywheel,E) clunking when changing gears.

Is the car lowered?if yes perhaps pinion angel is a factor.

Re check track lock kit,if you dont stack the plates and clutch right it will pop and make noise.Not enough carrier bearing preload will also cause this, allowing the ring gear and trac-loc to spin too freely and when going from coasting to accelerating, the gears teeth abruptly engage and make a clunking sound.
Another cause could be cracked axle tubes,if the PO beat it launching John Force style.Worth checking to rule out.
Binding UCA could also be contributing but that usually with the poly bushings.

In another thread you said this all started after a triple digit race.The T45 may need a rebuild or clutch is shot.clunking/hard shifting.My clutch was junk when I got my car had clunking and was hard to get reverse.

Like said at the beginning this is a mechanical soup with many ingredients.I'd start with Trac-lok and clutch.Unfortunately a quarter turn of a bolt will not remedy what you got going on,it's going to take some time.

Tight suspension and NVH for another day,get some good sticky tires and carve the street.

Hope this helped good luck.

G