hi all, hope someone here can help me out. so here it goes.

I have a 1997 camaro z28, with the t56 6 speed transmission.

I just got done rebuilding the transmission and getting my car back on the street. now I have another problem, not sure if its related to the transmission but I will start here. so I took it around the block after I got the transmission installed and I don't remember feeling anything weird. But I took the car on the freeway the other day and now I feel a vibration above about 3k rpm. I don't feel a vibration or anything below that rpm. the car has never shifted better, it was very rough to shift before and now it shifts beautifully. I wouldn't notice anything if I kept the car below 3k but of course I wanna get on it from time to time. it doesn't matter if I am in neutral or if I am 6o mph on the freeway. if it goes up above 3k it vibrates enough to concern me. I got underneath it and checked all the mounts and fluid levels, they are all fine and tight. I was concerned it might be the input shaft but I don't feel anything on the clutch when the vibration happens, I feel it mostly in the shifter and the car in general. to note, I also changed the clutch and the flywheel while the transmission was off. the car was also sitting for a year almost so I don't know if this could just be the gas affecting it at higher rpm. if anyone has any insight or knowledge that can help I would be appreciative. I am hoping to not take the transmission off the car but if I have to then I will do it. thanks for any help guys.

 

How does the vibration act under load. Is it worse going up hill or accerating? Better going down hill off throttle?

Does the gear matter? Will it vibrate in 1st gear over 3k?

 

doesn't matter what gear I'm in.

load on the transmission doesn't really matter, the car vibrates if I'm in neutral and rev the engine.

I haven't really taken it up a hill yet, where I live is pretty flat for my daily driving. but the higher the rpm the worse the vibrating gets. at idle I don't really notice a vibration, but once I rev it the vibration gets more and more pronounced the higher it revs. doesn't matter what gear or if in idle. I've put it in neutral on the highway and when the rpms drop so does the vibration.

 

What speed(s)? Does it do it going <10 mph? Clutch engaged or disengaged? Gotta think of everything that's rotating. Mentioned changing the flywheel...what did you go with? Flywheel should have had a counter weight for balancing.

 

it vibrates at any speed as long as the rpms are high enough. the clutch can be engaged or disengaged. I went with the RAM clutch from hawksmotorsports. when I changed the flywheel I didn't notice any counterweights. the flywheel is keyed so it can only go on one way.

 

Does it do it parked not moving when you rev the engine up to the 3K rpm mark?
Have you checked your fan and other accessories? Maybe unhook the fan belt/s and try it.
If the problem goes away then you need to narrow it down to what part is the problem.

 

You went with the Ram Flywheel as well? If so, there wouldn't be a counter weight, it'd be drilled for the proper balancing. Most OE flywheels are weighted like factory. If it does it with the clutch pedal to the floor, sitting still and engine at 3k rpm, then you narrowed the problem down the anything directly connected to the engine.

 

the car will vibrate sitting still being revved or with a gear engaged.

yes I did go with the ram flywheel.

there was absolutely no problem before I rebuilt the transmission. could this be a problem with year old gas? I don't think it would affect it that bad. of course i'm just nervous I messed something up but it shifts better than it has in the last ten years.

you are right that the car vibrating while not In gear with the clutch to the floor eliminates the transmission.

I did have a problem with overheating before this started happening. could that have something to do with it? should I drain the gas tank and put new gas in it and try? im reaching for straws here, tempted to take it to an actual mechanic but I know that's gonna cost me an arm and a leg.

 

Like I said check that fan, a bad fan clutch could do this and a fan problem could be related to the overheating.
Easy enough to eliminate that possibility as I posted above, take the belt off and see if it makes a difference.
You can also see if the fan spins free with no resistance from the fan clutch (assuming it's a clutch type fan) ,if it does it's shot.

 

so the fan in my car is an aftermarket driven off of electrical, not a belt. the overheating I resolved as it was a leak in one of my lines that I was able to fix fairly easily. removing the belt would just eliminate the power steering pump, alternator, ac compressor. my water pump is driven off the motor, no belt. my fan is electrical, no belt.