Drivetrain/suspension problems

[black34v6]

So --- get a soda and some snacks cause I gotta run down the story really quick here and it might take a little bit:

Back in 2005 - driving my 1994 Camaro 3.4L V6 after having broken in the Spec Stage 2 Clutch and installed a Polyurethane Trans Mount to my 5-speed manual (t5) - I happened to be on the 110N freeway heading onto the 91W. The interchange there is a fun dip to a 90* turn on which I *always* down-shift, hit the apex and floor it out of the turn just for s&g.

On this particular occasion I did the same as I had always done, and upon hitting third gear an flooring the accelerator - I hear an *extremely* loud BANG (almost a BAM noise) and suddenly the entire car is shaking. I was probably going above 75-80mph when it happened...

I pulled to the side of the road, convinced I had blown a tire (that's what it felt/sounded like) - made sure it was safe, got out of the car and did a complete walk around. No issues. All 4 tires were inflated with no signs of distress, bulges or damage/wear. So I get back in the car and accelerate back up again, to find the vibrations around 60-65 mph. We (my wife and I) were headed to a friends house, so we got there and since he was a car guy, we talked the matter over with him, deduced it was probably the U-joints giving way, and I resolved to fix them.

Did that. Bought two new u-joints and melted the old nylon out of the factory ones on my Ls1 STEEL driveshaft and replaced the U-Joints with Spicer U-Joints I bought from pepboys.

Vibration seemed gone, until I hit 70-75mph - I tried pushing past the vibration but it seemed like the faster I went the worse the vibration got. Never did manage to find a place where the vibration vanished, and I have been on a quest to eliminate since.

Without making this story too much longer, to date I have:

• Replaced Axle Bearings/Carrier Bearings
• Replaced rear with LS1 Rear End (3.42 gearing / full disc - after causing the pinion to grenade - long story)
• Replaced Rear Tires
• Replaced both Front Wheel Bearing Hub Assembly
• Replaced both Outer Tie Rod Ends
• Replaced Front and Rear endlinks
• Replaced U-Joints
• Had driveshaft rebalanced
• Replaced transmission (another long story)
• Adjusted transmission mount height to bring to proper height w/poly endlink pieces

I cant adjust my pinion angle because I have a TQ arm made by MAC which JEGS now sells, looks like this:


(kind of auto-adjusting).

As of right now if I get the car up to 3500 rpm in 4th gear (about 80mph) or above 2500 rpm in 5th (around 80mph), the entire car vibrates. Vibration is felt in the pedals and the middle-back of the driver's/passenger seats.

Anyway - would appreciate any info anyone can give me or suggestions. I'm sure I've replaced more parts on the car but those are the only pieces I can think of. If you mention something and I've replaced it I will definitely add it to the list of replaced/repaired parts.

Also - in 2005 I had my entire steering system rebuilt and replaced the stock v6 rack with a Z/28 steering rack - however it does *not* look like they replaced the steering components other than the rack itself, and I'm a little concerned about that...(rubber on the outer tie rods was 1994 original and very rotted/falling off when i replaced them).

Thanks for any help you can give.

-Russ

[cam98aro]

Re: Drivetrain/suspension problems

i would do the simple things first and check the balance of the tires

this is obviously not a drivetrain problem since the vibration happens at 80mph instead of different rpm's

[Skinny]

Re: Drivetrain/suspension problems

this is obviously not a drivetrain problem since the vibration happens at 80mph instead of different rpm's

You have that backwards. If the vibration occurred in a given RPM range, then you would most likely have an engine problem. In a given MPH range, not related to RPM, then the suspect is likely in the drivetrain or the related suspension.

As for your problem, black34v6, I would start looking at that torque arm. Make sure it's not bent. The rod in the front should slide freely in and out of the arm. Make sure there is not excessive play in the end. It should be a close fit inside the arm, but as I said, it should move freely and not get stuck anywhere. It may help to put some sort of grease on there. If you still have instructions for the arm, refer to that for what kind of grease to use. If not, a moly-based marine grease would probably be best.

[A fireman]

Re: Drivetrain/suspension problems

I would say start from your tires and work back towards the engine for parts that you have not replaced or had inspected. Also look on your under-body for any large scratched or dents, if you find one it should help lead to your faulty part.