Vibration issues

[Dan Jaeger]

Alright guys, I'm somewhat at a loss here. Just changed my transmission mount, with a rubber one from Oriellys (anchor) while I wait for my es poly one to get shipped. I'm getting a very noticeable vibration in my shifter. (93 z28 t56) it's really noticeable at about 40 - 50 mph, that's all the faster I've really gotten it since I put the c6 wheels on it. (Btw, didn't have this vibration before I put the wheels on) The shifter vibrates up and down probably close to half an inch quite rapidly, and it will do it regardless of whether I'm accelerating, decelerating, or even in neutral at those speeds. I had the wheels balanced and an alignment done right after I put them on too. Any ideas? Any input is greatly appreciated of course ;)

Oh yea, the rear tires are .9 in taller than the stockers I just took off.

[Fastbird]

Swap your old wheels back on and see if the vibration stays or goes.

[Injuneer]

Has anyone checked the wheels for runout, both radial and lateral?

[Dan Jaeger]

Runout? Sorry, no idea what that means.

[firebird_1995]

http://img.tapatalk.com/d/14/07/05/nubehahe.jpg

If the tire has a bulge or flat spot on the tread surface, it would have runout issue (radial). If the bead surface was formed improperly or the rim was bent it could have a vibration issue too(axial).

If the issue got worse when you changed tranny mounts, check the height of what you got versus what you had. Raising or lowering the transmission mount will cause the driveline angle to change. Most u joint manufacturers say anything more than 3° difference the pinion (or output shaft) should be avoided. Over 5° will shorten life greatly. Whatever angle the engine/transmission driveline is, the rear end pinion angle should match (-3° on the transmission, -3° on the pinion).

[Dan Jaeger]

It actually got better after I changed the mount, but there is still a notable vibration. I put the new and used mounts next to each other prior to installing it and they looked to be the same height. After driving it last night it seems to just be in the 40-50 mph range. I had it up over 90 with nothing more than your average vibration (for a 21 year old car with 175k on it)

[96LT1355Z28]

Like said above I'd swap wheels if your can and see if it changes or go get the ones you have checked and balanced.

[Dan Jaeger]

Went with poly engine/tranny mounts, no more problems. Went ahead and did my motor mounts when I did my headers. Thanks for the advice and suggestions everyone!

[jlo]

Good to hear you got it fixed, I was about to suggest to check the Torque arm mount..