vibration @ 2300-2500 in EVERY gear except Neutral??

jaymac

New Member
Feb 18, 2004
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Northern Mass
Just came from getting new tires put on the car, mounted, balanced, alignment w/ Steeda C/C plates. etc. a few minutes after leaving, i now feel this vibration. It feels like an internal vibration. It is not present in the steering wheel. You cannot really hear it (i.e., exhaust pipes hitting the underbody). It feels like a grinding vibration, and you can feel it through the gas pedal and shifter (AOD). loose Change in the console will also rattle. It only happens between 23 and 2500, then goes away. 1st through 3rd gear vibrate in that 23-2500 window, and still in OD, just not as pronounced. If you keep it in park or in neutral and rev it to the same RPM's or above, there is no vibration.
Any ideas on what it could be or how I should troubleshoot this?
Thanks~ jeremy
BTW, I do have 4.10's and an FRPP alum. DS, and have had them for more than a year w/ no problems... motor mounts were also replaced w/ HD ones less than a year ago.
 
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I wasn't sure..................and it's tough to do in an AOD............ but does it vibrate while rolling in neutral (like you get to to where it vibrates and drop it into neutral)?

Because it doesn't sound to be speed dependant but is RPM dependant, I still was thinking an exhaust issue or something else with a sweet-resonance-spot in that 200 RPM window. Driveline issues after the trans were not my first guess.

I'd simply go over everything the shop touched during the install and see if you note anything. Because you said it almost feels like a grinding issue, you might see some sort of carnage or signs of interferance.

Good luck Jeremy.
 
How do I check the U joints again? See if the driveshaft has rotational slack or a different kind of test? I didn't suspect it initially because the FRPP alum. DS comes with new u- joints, but I guess that doesn't mean anything... I haven't jacked it up and looked, but I'll need to go through and check the motor mounts again, although it feels harsher, not like a loose rough tumbling, but a tighter rattling... does that make sense? I'm not ruling out exhaust. It's def. RPM dependant, not speed dependant, and it wasn't as severe on the drive home. Is there a chance it could've been anything to do with the new tires construction themselves, and it might go away after breaking in the tires?
Or could it be the balancing of the new tires that would vibrate strictly in a 200 RPM window?
So how do I do that U-joint check?
Thanks for your help everyone, as always!
 
How do I check the U joints again? See if the driveshaft has rotational slack or a different kind of test? I didn't suspect it initially because the FRPP alum. DS comes with new u- joints, but I guess that doesn't mean anything... I haven't jacked it up and looked, but I'll need to go through and check the motor mounts again, although it feels harsher, not like a loose rough tumbling, but a tighter rattling... does that make sense? I'm not ruling out exhaust. It's def. RPM dependant, not speed dependant, and it wasn't as severe on the drive home. Is there a chance it could've been anything to do with the new tires construction themselves, and it might go away after breaking in the tires?
Or could it be the balancing of the new tires that would vibrate strictly in a 200 RPM window?
So how do I do that U-joint check?
Thanks for your help everyone, as always!

That will work fine, look for play eitehr way!
 
Yep. I grab the DS on either side of a given U-joint and try to twist the parts towards and against eachother (like giving the DS an Indian rug burn).
Being RPM dependant, I still dont think this is likely however..............

Good luck.
 
Well if it started as soon as you left the tire and alignment shop I would say it has to be the tires. Sometimes they do not get it perfect. I would head back and let them know. Could be just a quick balance check.