A lightweight Warner SR4 4-speed was introduced in six cylinder models in late 1976 and is used in all 1980-81 models. The four cylinder uses a Warner HR-1 4-speed transmission through 1979. The SR4 transmission has a cast aluminum case and extension housing, while the HR-1 has a cast iron case and an aluminum extension housing. The SR4 and HR-1 have internal, non-adjustable shift linkage. In 1982 a new Warner (T4) four speed and an optional Warner (T5) five speed transmission were introduced. Both are lightweight and feature an integral mounted shift mechanism.
SR4 and HR-1 transmissions have metric fasteners in most threaded holes.
An identification tag, containing Warner and American Motors part numbers, is located at the rear of the transmission. The Warner model number is also usually cast into the side of the case.
The model 150T 3-speed transmission was also used through 1979. A nine character identification code is stamped on the left front case flange, but does not give the model number.
The 150T can readily be identified by its nine bolt top cover which is narrower in the front. Unlike the Warner transmissions, it does not have a drain plug: lubricant is drained by removing the lower extension housing bolt. Warner 3-speeds have a rectangular top cover, usually with four or six bolts.