Any help or knowledge of this constant down shift problem would help . I have a 99 with a 4.2 4R70W with 3.55 rears ,super chip ,airraid ,flowmasters Bosch platinum plus 4 and less than 25,000 miles . Been to the dealer several times regarding the down shift and they always say it`s O K . I was going to service the trans a few days ago and noticed a sticker in the side of the pan . It referred to TSB 98-4 . It also gave an 800 number to call until 8-31 99 . I purchased the truck after that . The dealer sure is no help but one of the parts guys remembered the TSB , but has not been able to find a copy for me . this thing is so bad you cannot use the cruise control without it dropping a couple of gears . sometimes it will drop into 2nd gear at 70 m p h . I`m a retired tech and not ignorant of the workings of an auto . trans . and I know the dealer has to have ran into this before . I would like to hear from anyone that has had this problem ao any knowledge of obtaining this Tsb . :o
Ed