MPH Specific Vibration??
02-28-2005, 02:40 AM
#1
12 Second Club
Thread Starter
iTrader: (2)
Join Date: Sep 2004
Location: Deland, Florida
Posts: 366
Likes: 0
Received 0 Likes
on
0 Posts
MPH Specific Vibration?? I have a 2000 T/A, A4, 3.42 gears. I have begun to notice that when I am crusing at 25-28 MPH there is a pronounced whine/vibration coming from what seems to be my entire driveline. I can feel it in the gas pedal and the shifter handle. It only happens at this speed.
I just recently had my driveshaft off, maybe a U-Joint? I had also increased the line pressure via a Hand Held Tuner, but since discovering this problem I removed it......the vibration is still there. Maybe a problem with over-taxing the pump?
I have not had the 3.42's for long (1200 Miles).....there is a little bit of gear whine but it does not kick in until 45MPH or so. When the car vibrates, if I put the shifter in neutral it goes away. The car is barely in OD at 25-28mph at around 900RPM or so (the equivalent of doing 38-40 w/the 2.73's). If I pull the shifter into third the vibration is there but it is not as pronounced. The car will accelerate smoothly from this speed, but if I have the car in 3, the car will begin surging at about 25 and below upon deceleration with my foot off the gas (this does not happen if gear selector is in OD). Any suggestions as to what is going on here? The car has never had this problem until now (20-30 miles ago).
I just recently had my driveshaft off, maybe a U-Joint? I had also increased the line pressure via a Hand Held Tuner, but since discovering this problem I removed it......the vibration is still there. Maybe a problem with over-taxing the pump?
I have not had the 3.42's for long (1200 Miles).....there is a little bit of gear whine but it does not kick in until 45MPH or so. When the car vibrates, if I put the shifter in neutral it goes away. The car is barely in OD at 25-28mph at around 900RPM or so (the equivalent of doing 38-40 w/the 2.73's). If I pull the shifter into third the vibration is there but it is not as pronounced. The car will accelerate smoothly from this speed, but if I have the car in 3, the car will begin surging at about 25 and below upon deceleration with my foot off the gas (this does not happen if gear selector is in OD). Any suggestions as to what is going on here? The car has never had this problem until now (20-30 miles ago).
02-28-2005, 06:02 AM
#3
10 Second Club
iTrader: (4)
Join Date: Jul 2004
Location: hatboro, pa
Posts: 1,284
Likes: 0
Received 0 Likes
on
0 Posts
is the vibration with the converter locked? that could be the problem- locking up too early and lugging the engine. i have some vibration after 70mph, which i was thinking driveshaft, or unbalanced tires or wheels, but it stays if i go into nuetral so i think we have different problems.
maybe try adjusting the force-motor current tables to have the converter not lock up so hard/ hold so hard, i get the same surge on deceration but i have the force motor current table at higher pressure (via hp tuners) so i can save my lockup clutch. also the tcc apply/release speeds can be adjusted.
aftermarket/ broken trans mount is also something to check out. jack the car up and stick a pry bar in there to try and lift the trans up off of the crossmember. you'll be able to clearly tell if the mount is trashed (i killed one a month after owning the car...)
maybe try adjusting the force-motor current tables to have the converter not lock up so hard/ hold so hard, i get the same surge on deceration but i have the force motor current table at higher pressure (via hp tuners) so i can save my lockup clutch. also the tcc apply/release speeds can be adjusted.
aftermarket/ broken trans mount is also something to check out. jack the car up and stick a pry bar in there to try and lift the trans up off of the crossmember. you'll be able to clearly tell if the mount is trashed (i killed one a month after owning the car...)
02-28-2005, 11:52 AM
#6
12 Second Club
Thread Starter
iTrader: (2)
Join Date: Sep 2004
Location: Deland, Florida
Posts: 366
Likes: 0
Received 0 Likes
on
0 Posts
I made sure that the driveshaft went it the same way it came out...caps, bolts and all. I will check the torque specs again but I think they were right.
The car is in overdrive, but the torque converter has not yet locked up.
When the vibration happens it also sounds like there is a low pitch whine...almost like a pump whine or something <sounds kinda like an amplified fuel pump...for sound reference>. The vibration is ALWAYS there, it is not an intermittent problem, and the MPH is always the same. When this happens, if I pull the tranny down to 3 the noise and vibration is still there but less intense. If I pull the tranny down to 2 then it isn't there at all. It seems to be speed/rpm specific.......lower RPM 900-1100, 25-28 MPH, and mostly in Overdrive <no converter lockup>. If I accelrate, it goes away.
I still have the stock 62K converter and the stock 62K Tranny. I know that my torque arm bushing is pretty ate up, could this contribute to a whine/vibration?
The car is in overdrive, but the torque converter has not yet locked up.
When the vibration happens it also sounds like there is a low pitch whine...almost like a pump whine or something <sounds kinda like an amplified fuel pump...for sound reference>. The vibration is ALWAYS there, it is not an intermittent problem, and the MPH is always the same. When this happens, if I pull the tranny down to 3 the noise and vibration is still there but less intense. If I pull the tranny down to 2 then it isn't there at all. It seems to be speed/rpm specific.......lower RPM 900-1100, 25-28 MPH, and mostly in Overdrive <no converter lockup>. If I accelrate, it goes away.
I still have the stock 62K converter and the stock 62K Tranny. I know that my torque arm bushing is pretty ate up, could this contribute to a whine/vibration?
Trending Topics
03-01-2005, 01:23 AM
#9
12 Second Club
Thread Starter
iTrader: (2)
Join Date: Sep 2004
Location: Deland, Florida
Posts: 366
Likes: 0
Received 0 Likes
on
0 Posts
I have also noticed that while decelerating <foot off gas> the car pulsates, almost like a "catch-grab-catch-grab" like a warped rotor. OD is not too bad, 3 is worse, 2 worse yet, etc... It only does it in gear, in Neutral it is not present. Could this possibly be a bad U-Joint? I have also noticed a couple "clunks" this week when I put the car into gear. It doesn't feel like a broken tranny mount because I can go WOT and there is no "slam" so to speak <tranny hitting tunnel>.
