Couple of drivetrain issues....
05-10-2013, 09:45 AM
#1
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Couple of drivetrain issues.... I moved this here since, after over a hundred views, I had yet to receive a single reponse in the newb forum haha
Have recently noticed a couple of sounds and vibrations/thuds that are alarming. One that I've had for quite some time happens on the 1-2 shift (a4) during WOT. The best way I can describe it: a whip lashing like on a cheesy action flick...a wu-TSHH. It only occurs when the tranny shifts from 1st to 2nd gear during WOT. If I let off the gas slightly so that the shift happens a fraction of a second sooner it doesn't make the noise, nor does it make the noise during any of the other shifts, regardless of how hard I'm pushing the car. I've had it for quite a while now but I've altered my driving habits to where it doesn't do it in fear that I will make whatever is causing the noise worse. I honestly can't tell where the noise is coming from since it only does it when I'm flooring it but it seems to be originating from the rear of the car, not the engine or tranny areas.
The other problem arose about two days ago while going to and from work. The rear of the car began shuddering ever so slightly when mildly accelerating from a stop. The shuddering is so slight that I can really only feel it in the pedal. It doesn't do it if I barely take off, and it doesn't do it when I hammer the pedal, either. Only on mild scoots at maybe 1/3 to 1/2 throttle. To make matters worse, yesterday I began to feel a dull thud in exchange for the shudder. So, 0-1/3 throttle from stop = no noticeable issues. 1/3 throttle gives shudder for a fraction of a second. 1/2 throttle = single dull thud that feels almost like a bowling ball or something hitting the back of the trunk.
I did some quick searches with my phone last night regarding that shudder/thud and I came up with two possibilities. 1) differential fluid needs changing to some specific synthetic. This seems far-fetched to me but a couple users in old posts on other sites claimed that was the issue. 2) center support bearing is bad and apparently I need to replace the entire driveshaft.
What is the center support bearing, where is it so I can inspect it, and what signs will I need to look for if it has gone kaput?
Any thoughts, suggestions on either of these issues? This is my only DD so if the problem is a big one I need to fix it ASAP before I'm left stranded somewhere.
Edit: It doesn't feel like someone is hitting the car with a bowling ball....it feels/sounds like a bowling ball is sitting in the trunk and rolling back and thudding against something when I take off.
Have recently noticed a couple of sounds and vibrations/thuds that are alarming. One that I've had for quite some time happens on the 1-2 shift (a4) during WOT. The best way I can describe it: a whip lashing like on a cheesy action flick...a wu-TSHH. It only occurs when the tranny shifts from 1st to 2nd gear during WOT. If I let off the gas slightly so that the shift happens a fraction of a second sooner it doesn't make the noise, nor does it make the noise during any of the other shifts, regardless of how hard I'm pushing the car. I've had it for quite a while now but I've altered my driving habits to where it doesn't do it in fear that I will make whatever is causing the noise worse. I honestly can't tell where the noise is coming from since it only does it when I'm flooring it but it seems to be originating from the rear of the car, not the engine or tranny areas.
The other problem arose about two days ago while going to and from work. The rear of the car began shuddering ever so slightly when mildly accelerating from a stop. The shuddering is so slight that I can really only feel it in the pedal. It doesn't do it if I barely take off, and it doesn't do it when I hammer the pedal, either. Only on mild scoots at maybe 1/3 to 1/2 throttle. To make matters worse, yesterday I began to feel a dull thud in exchange for the shudder. So, 0-1/3 throttle from stop = no noticeable issues. 1/3 throttle gives shudder for a fraction of a second. 1/2 throttle = single dull thud that feels almost like a bowling ball or something hitting the back of the trunk.
I did some quick searches with my phone last night regarding that shudder/thud and I came up with two possibilities. 1) differential fluid needs changing to some specific synthetic. This seems far-fetched to me but a couple users in old posts on other sites claimed that was the issue. 2) center support bearing is bad and apparently I need to replace the entire driveshaft.
What is the center support bearing, where is it so I can inspect it, and what signs will I need to look for if it has gone kaput?
Any thoughts, suggestions on either of these issues? This is my only DD so if the problem is a big one I need to fix it ASAP before I'm left stranded somewhere.
Edit: It doesn't feel like someone is hitting the car with a bowling ball....it feels/sounds like a bowling ball is sitting in the trunk and rolling back and thudding against something when I take off.
05-10-2013, 01:04 PM
#3
if you have a v-6 car i believe those had a 2 piece drive shaft. in that case the drive shaft is made up of two pieces and there is a center support with a bearing that is mounted to the underside of the car. if you have the v-8 (LS1) then the drive shaft is one piece.
for the wot problems that's the reality with these cars and is kind of hard to pinpoint the problem without experiencing first hand, could be caused by the drive line or suspension, may also be a worn transmission, may also be normal since your wot on a 1-2 shift.
but for normal driving light load the things i would look into are the transmission mount like said, also motor mounts given your location. heat, abuse, and time will cause the oem rubber mounts to need replacing. inspect/replace your torque arm mount on the rear of the transmission and inspect your torque arm for fatigue, cracks, and breakage. also check/replace ujoints and inspect the slip yoke going into the transmission for play. after that if the noise is coming from the rear of the car then the next common breakage is something in the oem axle. you can read all the stories in the gears & axles section about broken and replacing rear axles.
for the wot problems that's the reality with these cars and is kind of hard to pinpoint the problem without experiencing first hand, could be caused by the drive line or suspension, may also be a worn transmission, may also be normal since your wot on a 1-2 shift.
but for normal driving light load the things i would look into are the transmission mount like said, also motor mounts given your location. heat, abuse, and time will cause the oem rubber mounts to need replacing. inspect/replace your torque arm mount on the rear of the transmission and inspect your torque arm for fatigue, cracks, and breakage. also check/replace ujoints and inspect the slip yoke going into the transmission for play. after that if the noise is coming from the rear of the car then the next common breakage is something in the oem axle. you can read all the stories in the gears & axles section about broken and replacing rear axles.
