So I've noticed a funky power cut when I'm WOT in 3rd and shift into 4th. The power cuts for a bit and the loss of traction light blinks. Then after a second it picks back up. This happens with the traction control engaged. I haven't tried it with it turned off to compare.
Could it be that it's controlling wheel spin in 4th?? Anybody else get this? Almost feels like clutch slip...