Vibration from Rear Under Neutral Throttle
04-04-2007 | 08:24 PM
#1
Vibration from Rear Under Neutral Throttle First off, what I mean by "neutral throttle" is that there is no load on the drivetrain, positive or negative.
This only happens at higher speeds (65mph and up) and I get a vibration coming from the rear end, right under the back seat. I've gotten under there and it doesn't look like anything is binding, but I'm at school and don't have access to very many tools (i.e. don't have an angle finder to check pinion angle). Another thing is that the rear diff cover leaks a little, and the car sat for about a month and a half, so it could be low on fluid, BUT I don't have the 14mm allen wrench I need for the stupid plug on my 12-bolt
.
Anybody got any ideas? I'll be going home tomorrow, and will have access to pretty much every tool I could need short of a plasma cutter.
EDIT: Also, didn't notice this until I put the new KYB AGX shocks on, but I had also just gotten the car back from sitting waiting to go to the body shop.
This only happens at higher speeds (65mph and up) and I get a vibration coming from the rear end, right under the back seat. I've gotten under there and it doesn't look like anything is binding, but I'm at school and don't have access to very many tools (i.e. don't have an angle finder to check pinion angle). Another thing is that the rear diff cover leaks a little, and the car sat for about a month and a half, so it could be low on fluid, BUT I don't have the 14mm allen wrench I need for the stupid plug on my 12-bolt
.Anybody got any ideas? I'll be going home tomorrow, and will have access to pretty much every tool I could need short of a plasma cutter.
EDIT: Also, didn't notice this until I put the new KYB AGX shocks on, but I had also just gotten the car back from sitting waiting to go to the body shop.
04-05-2007 | 11:06 PM
#2
Launching!
Joined: Jun 2005
Posts: 236
Likes: 1
From: Windsor, Ont
I would start with checking your pinion angle, and if your torque arm is adjustable make sure that all bolts are tight. Also check all bolts holding the shocks to make sure they are tight. If these are okay, then you might want to check the rear diff.
04-07-2007 | 04:47 PM
#5
Well, finally got the thing taken care of. Turns out a torque arm locknut on the adjuster had come loose and the rear end had worked its way upwards. Pinion angle was dead on 0* 
So basically when I would clutch in, the pinion angle would go to 0* and the drivetrain would become unhappy.
Reset it to -2.5* (poly mounts on everything, so that's the number I'd go with) and took it for a spin and no noise or vibration. Now it's sitting in the garage waiting for the locktite to cure
Bottom line is I think that when I had my clutch installed (I was at school and had no access to the tools needed to do it myself) I think the shop may have forgotten to locktite the nuts when they reset the pinion angle. Anyways, hope this helps anybosy else having the same problem, and thanks for the suggestions.
Jim
So basically when I would clutch in, the pinion angle would go to 0* and the drivetrain would become unhappy.Reset it to -2.5* (poly mounts on everything, so that's the number I'd go with) and took it for a spin and no noise or vibration. Now it's sitting in the garage waiting for the locktite to cure
Bottom line is I think that when I had my clutch installed (I was at school and had no access to the tools needed to do it myself) I think the shop may have forgotten to locktite the nuts when they reset the pinion angle. Anyways, hope this helps anybosy else having the same problem, and thanks for the suggestions.
Jim
