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

Injuneer

You never actually said you replaced the tranny mount after the "bang", although you replaced the tranny. Didn't the V6 have an oddball "hydraulic" tranny mount, because of the inherent vibrations of the V6 engine? And wasn't the 2-piece DS used to cancel out some harmonics caused by the V6 valley angle?

Have you had the rear wheels checked for runout?

Have you checked to be sure you have the correct U-joints?

The torque arm is not "kind of auto-adjusting". It has a slider that accomodates the changes in length the occur in the DS as the suspension moves up and down, and the slider goes in and out of the tranny tailshaft housing. Have you checked to verify adequate clearance between the nose of the slider and the tranny output shaft/seal? You need at least 1/2" clear with the vehicle at normal ride height.

We can move this to "Suspension...." of "Drivetrain". What is your preference?

Z28SORR

Didn't see anything about checking Motor Mounts?

97droptop

Have you checked your wheel balance / wheel true? I now have a GTO (sold the camaro. big mistake). GTO's have a terrible problem in regards to vibration. It appears at least in the GTO's, a lot of the vibration at speed is attributed to out of round wheels, crappy wheel balance, and/ or poorly torqued wheels. Our vibrations manifest with a severely vibrating steering wheel. However when I blew the tranny mount in my 97 LTI Auto camaro, the tranny sounded like it wanted to come thru the floor. I then replaced the mount with a urethane one and got a vibration(minor) at low speeds due to the urethane mount. I guess my point is, since you stated that you checked hubs, and all sorts of bushings and mounts, I might make sure the wheels are balanced, and that the wheels are not bent first. It seems like a good starting point. (Cheep too if you havent already tried it). It might just be enough to set of some harmonic imbalance in the suspension at speed. You also stated that the pedals pulsate. Is it possible that if you bent the wheel, or even maybe a rotor(dont know how you might have done that but hey, any thing is possible) that the vibration would thus transfer to the pedals? just my $.02 worth i guess.

95z28onjuice

I would look at what you had done just prior to the issue at hand. the trans mount is it broke did it brake? something hit the road when you went into the dip? anything have any marks on them? i would look at that TQ arm to make sure its sliding correct, that would cause the pinion angle to be incorrect. also if the trans mount is busted,

Injuneer

"Black34v6" hasn't been back to the site since his original post 4 days ago.