It is estimated that just over 15,000 units were built. Most were made for the 1974 model year (PA136 chassis), but the effect of the energy crisis on sales caused Mazda to restamp many of the 1974 models with a prefix "S", designating them as 1975 models; (SPA136). Approximately 700 units were built for the 1976 model year, when the four-speed manual transmission was upgraded to a five-speed. Mazda invested in a moderate redesign for the 1977 model (PA236), updating its electrical systems and adding a cab stretch for increased comfort. About 3,000 units were manufactured, after which the REPU was discontinued due to poor sales.