To complete the previous post...installed the new IPS last weekend, tranny was still pretty noisy on first drive. However after driving about 75 miles it's noticeably quiter. Almost no whine in 1st thru 4th. 5th is still objectionably noisy, but much better and getting better with miles (it seems).
My hope is that with time the new gear will wear in, matching it's neighbors and be acceptable.
Actually, a small amount of gear noise does seem to be in character with a 51 3/4 ton flat bed truck

RR