Anyone have this happen? I'm converted to a tri link and panhard bar but the lower links are stock so the distance from diff to trans shouldn't have changes.

 

If your car is lowered your rear is closer to the transmission if you are using the stock lower links.

 

 

Just thinking out loud. Have seen the car running while you are underneath?

Maybe a shorter drive shaft. Mine is pretty close and I'm not too lowered.

 

I suspect you are correct, I have a replacement driveshaft from mazdatrix possibly having less clearance, maybe that, the tri link and lowered ride height add up to some rubbing.

I'm run typical track car ride heights for our cars and hadn't heard anyone mention it before

 

The incline of the control arms are 3 to 4 inches higher at the axel than the mount point on the chassis.

 

Thats probably too low, shouldnt be too much lower than level, in any case the prop shaft should be short enough to accommodate the whole suspension travel. Whats your pinion angle like?
is it possible your 3rd link is too short and your pinion is noseing down?

 

The driveshaft should have about 3 degrees of tilt toward the trans. Level or negative angle is not good.

 

 

I dare say he is referring to tailshaft angle. I would find it hard to imagine the tailshaft is angleing up toward the back of the car no matter how much you lowered it.
Have you checked pinion angle? gearbox output shaft and diff pinion should be within 1 degree of each other (parallel) and the tailshaft on an angle pointing down to the diff.

 

Sinple misunderstanding. I can't really get under the car until the weekend. I'll update if anyone is Intrested