_Remi

Hi,

Well, everything is starting to be really fine with the car but there is this new thing (or relatively new, it probably started a month ago) that makes me feel a little scared.

When I launch the car in first gear, not necessary reving high or launching too low (there is no pattern) it rumbles and my shifter is shaking like crazy for two or three seconds. It seems to be coming from the transmission or the drive shaft (although not sure) and it is definitely not something related to the engine (dyno tuned when perfectly fine).

Any idea?

It was not happening before and without any knowledge on that the feeling is like something not balanced or something really loose. Can it simply be resonance due to the new flowmaster straight line?

Thanks!

Gun Jam

If you can feel in the shift handle and it gets worse then gets better as speed increase it could be U joints...Thats all the comes to mind right now.

-Gun

_Remi

Yes I can feel it in the shift handle but not only.

I am thinking that it happened when I had my head changed (absolutely no link I guess) and my stock exhaust was replaced by flowmaster 40 series. Can something shake / be loose / touches something that has to do with the transmission?

About U Joints, is that a big problem?

_Remi

I am also thinking that my rear main seal has been leaking for about the same time. It has been changed yesterday so that problem is fixed and the rumbling / shaking is still there.

Can it be linked? Could it be oil going somewhere it should not?

67mustang302

You don't want loose u joints. Are you sure you're not getting wheel hop? More power = less traction, generally.

Gun Jam

have you checked that the exhaust is has good clearance? Perhaps under load the engine torque is causing the exhaust to hit the frame of the car...

But if you can feel it in the shift handle im guessing drive line. my car develops a vibration above 80 mph that I can feel in the shift handle...I think...I hope its due to a worn slip yoke...I can not drive through the vibration...it only gets worse...

So start with checking/replacing U joints and while your down there flex the slip yoke there should be no play where it enters the tailshaft...if there is it might time for a new bushing/yoke...but it sounds like its something else.

-Gun

_Remi

Well, I don't really know if that's wheel hop or not but I am 100% positive that it happens when I don't launch the car like crazy. Even a normal launch would do it but I noticed that it happens more when I am launching the car uphill. Once the car is rolling, no problem.

Wheel hop or not wheel hop?

Also, from what I read here since I had a rear main seal leak it could be oil in the clutch?

_Remi

If that's wheel hop (http://www.youtube.com/watch?v=DOVtnAZYBgM) then that is not my problem. I am starting the car slowly (or at least normally).

Gun Jam

that would cause clutch chatter I suppose that could simulate a Drive line vibration

doesnt sound like wheel hop

Now if you are in 1st dead slow (5mph) with clutch all the way out and accelerate normal will it do it?

Or does it only do it when your letting out the clutch?

-Gun

_Remi

I can really feel it when I engage the clutch and it never last more than 2 seconds. I am not sure that it does it when the car is already moving (and I engage the clutch in first) however I have a feeling that it does it more when I am launching up hill.