I suggest dropping the pan and pulling out the filter,pull the filter apart and make sure there is nothing abnormal inside the filter.

I say this because i had the SS4000 convertor and found a non lock up issue started after about 15000 miles,i pulled mine apart to find a few pieces of lock up material inside it. ( i did not know what it was at the time)

Called Yank,talked to them about my issue with non-lockup. they asked for the vertor back and found a part of the lock up clutch had come apart.
They fixed it and all was good.

I'm not saying the YOU have a bad convertor or that Yank has troubles,just saying you might want to check it out is all.


P.S. this was over 1 year ago.

Good luck,Dave