slight vibration when in D(3rd)?
slight vibration when in D(3rd)? I noticed the other day that when in Drive(3rd) I feel(hear) a vibration??? Its only in 3rd gear. I put this thread in the A4 section...i guess this is the right section. You guys ever heard of this?? Whats the deal? Im not really worried about it just wondering. I take it its not serious, but thats why im posting this thread cause im not sure. TIA
Joined: Nov 2003
Posts: 6,216
Likes: 236
From: Wichita KS / Rancho San Diego
There have been some threads on this ... do a search and you'll find some good reading but not too many answers. FWIW, I have a similar thing, especially pronounced about 2200-2500rpm and in third only.
A trans mount problem will show up worse at higher
torques (where the weight of the trans is no longer
enough to keep it seated).
A balance problem will show up with speed rather
than torque. If you have a vibration band that does
not seem to care whether it's 1/4 or 1/2 throttle, but
follows road speed rather than engine speed, then
look for tire issues, worn shocks (failing to damp out
tire irregularities), etc. Especially if this has come on
only by wear and not by modification. Another
possibility is flexplate cracking, on later years, this
failure can come up anytime but should track torque
& RPM more than road speed.
torques (where the weight of the trans is no longer
enough to keep it seated).
A balance problem will show up with speed rather
than torque. If you have a vibration band that does
not seem to care whether it's 1/4 or 1/2 throttle, but
follows road speed rather than engine speed, then
look for tire issues, worn shocks (failing to damp out
tire irregularities), etc. Especially if this has come on
only by wear and not by modification. Another
possibility is flexplate cracking, on later years, this
failure can come up anytime but should track torque
& RPM more than road speed.
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You would have to squint through the inspection
porthole, maybe a dental mirror and flashlight. The
late-years cracking seems to happen at the skinny
parts of the "web", rotate it slowly to check them
all out, there have been some fairly good pics of it
posted here before though I don't have any saved
of that. If you slog through all the search hits from
"flexplate crack" you should find good examples.
porthole, maybe a dental mirror and flashlight. The
late-years cracking seems to happen at the skinny
parts of the "web", rotate it slowly to check them
all out, there have been some fairly good pics of it
posted here before though I don't have any saved
of that. If you slog through all the search hits from
"flexplate crack" you should find good examples.
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i had/have the same thing. i thought u-joints first. i changed them, made it worse (damn cheap parts, same boxes, different clips) anyway, i noticed two enourmous weights on my driveshaft. one on the front, one on the back, in a almost perfect straight line from one another. a friend of mine had a spare steel shaft from a 93Z, so i swiped it and it seems better. is the aluminium shaft not absorbing as much vibration? just a thought.
Teching In
Joined: Jun 2006
Posts: 14
Likes: 0
From: Statesville, NC
Vib But if it was the driveshaft why whould the vibration be worse one minute and not as bed the next time at the same speed and rpms? Just wondering because i have been having the same problem. 
Mine vibrates in lockup around 40mph with my ss3600 stall.
Also FWIW I had a bad trans+motor mounts a few months ago and only way I knew was the first initial hit from wot. No vibrations. Just a clunk sound and as if the feeling of the motor and trans were shifting to the rear. It actually kept me from hooking at the track.
Also FWIW I had a bad trans+motor mounts a few months ago and only way I knew was the first initial hit from wot. No vibrations. Just a clunk sound and as if the feeling of the motor and trans were shifting to the rear. It actually kept me from hooking at the track.
FormerVendor
Joined: Oct 2006
Posts: 3,123
Likes: 3
From: D-F/W
I'm sorry to say this... but problems with cars do not get solved because the folks diagnosing the condition are not taking the time to understand it properly.
Once again, jimmyblue has some great comments here as he does in other threads. The reason this problem never seems to get resolved is that no two vibrations are the same. They actually occur at different frequencies which are very combination and load dependent. Therefore, it takes someone who is willing to put the time into solving the problem.
I personally have chased vibrations on cars for years. As a technician on the line at new car dealerships, and as a shop owner as well. Sometimes on late model F-bodies I see worn torque arm mounts, transmission mounts, engine mounts, exhaust mounts, driveshafts that have lost their balancing weights, out of round tires, bent wheels, cracked flywheels... I could go on and make one heck of a list. But I think you get the idea.
There is no one single fix for all those types of symptoms. Begin by bringing the engine up to the related rpm in park. If it does it then there is an issue with the rotating mass. If it does not, it is outside the transmission and engine... either way, use a very decisive process of elimination and you'll find it!
Hope that helps in some way!
g
Once again, jimmyblue has some great comments here as he does in other threads. The reason this problem never seems to get resolved is that no two vibrations are the same. They actually occur at different frequencies which are very combination and load dependent. Therefore, it takes someone who is willing to put the time into solving the problem.
I personally have chased vibrations on cars for years. As a technician on the line at new car dealerships, and as a shop owner as well. Sometimes on late model F-bodies I see worn torque arm mounts, transmission mounts, engine mounts, exhaust mounts, driveshafts that have lost their balancing weights, out of round tires, bent wheels, cracked flywheels... I could go on and make one heck of a list. But I think you get the idea.
There is no one single fix for all those types of symptoms. Begin by bringing the engine up to the related rpm in park. If it does it then there is an issue with the rotating mass. If it does not, it is outside the transmission and engine... either way, use a very decisive process of elimination and you'll find it!
Hope that helps in some way!
g
