General Manager Gillberg led SAT through an extensive renewal of the whole product range. The Sisu S-series lorries were a result of this; the first example, light forward control SK 150 was introduced in 1980. The new model series was designed in a such manner, that the same cabin modules could be used for conventional cabins as well as forward control models at different heights. Due to this, the company could offer a comprehensive selection of cabins for different purposes. The development programme had, however, demanded excessive amount of money and the company main owner, the state, removed Gillberg from office at end of 1983. He was replaced by Jorma S. Jerkku who immediately started a heavy reorganisation programme. The company management was cut smaller and moved from Fleminginkatu to Konala in 1985. After some other functions were moved to Karis and Hämeenlinna, the Fleminginkatu premises were sold. Car sales, as well as Iveco representation were discontinued at the end of 1988. In the same year the plastics factory in Mäntyharju was separated under name Simex Oy and sold. Although Jerkku's actions were shocking to many, he by all odds stabilised the company. On the other hand, the new organisation setup led to fragmentation of engineering operations between lorry, terminal tractor and military vehicle segments, and significant loss of synergy.