I would change out the present
oil to any name brand 10/30 conventional
oil, then get the engine and
oil fully warmed up to operating temp...
then get out on a deserted road somewhere,go thru the gears normally and when you get to 3rd gear,don't punch it, but accelerate quickly to say 5500 rpms,when you hit 5500 rpms, let off the gas and coast back down to about 2000 rpms,then accelerate back up to 5500 rpms all the while leaving it in 3rd gear......... do this 6 to 10 times in a row and watch your temp gauges....then cruise for a few miles in high gear to let things cool off and repeat one more time.......
if this doesn't work, then I'm afraid you may need to pull the engine down...
BTW: you shouldn't put any
synthetic oil in it until it is fully broken in and have at least 500 miles on it.....
David