transmission To permit the axial hole in the pinion shaft the drive pinion and gear are two pieces coupled by a shrink fit Currently the pinion gear and shaft are serviced only as an assembly The drive pinion shaft is directly connected to the transmission output member Preloaded tapered roller bearings support the drive pinion at fore and aft locations in the differential carrier The hypoid ring gear is bolted to the differential case which is mounted by preloaded tapered roller bearings on each side of the differential carrier Components of the differential assembly are conventional with the exception of the side gears which have integral elongated splined hubs which project to the outboard extremity of the differential case and cover to receive the axle shaft universal joints Axle ratios of 3 27 to 1 are used as standard with three speed four speed and automatic transmissions through application of an eleven tooth pinion and 36 tooth ring gear All transmissions can be used with the optional 3 55 to 1 ratio provided by a 9 32 tooth combination pinion and ring gear The speedometer drive gear is now pressed onto the drive pinion shaft as compared to the integral gear which was machined into the pinion shaft in 1960 Service replacement drive pinions will have the speedometer drive gear installed in production The nylon driven gear is mounted in the differential carrier Rear axle assemblies used with three or four speed transmissions and those used with automatic transmissions have fundamental differences in lubrication drive pinion design and mounting hub provisions for the clutch release bearing or converter stator respectively Lubricant requirements for the manual transmissions and rear axle are identical Therefore when this driveline is used the lubricant Multipurpose Lubricant SAE 80 cycles between the axle and transmission Although the lubricant is common individual filler plugs are provided in both the axle and transPERIODIC M LUBRICANT Differential Carrier The rear axle lubricant should be checked each 1000 miles and replenished as necessary with Multi purpose Lubricant SAE 80 Axle lubricant should be drained and replaced at the end of the first 1000 miles to eliminate any loose material from the sump which results from breakin After the initial 1000 drain axle lubricant should be changed seasonally or every 10 000 miles maximum mission as a lubricant dam is formed between the two units which prohibits a common sump Automatic transmission rear axles are sealed to prevent axle lubricant from entering the transmission The automatic transmission rear axle uses Multipurpose Lubricant SAE 80 whereas the automatic transmission requires Automatic Transmission Fluid Type A common in most automatic transmissions Drive pinion design for the two rear axle assemblies varies mostly in overall length splining for adaptation to the transmission and sealing The manual transmission axle pinion shaft extends forward only to the pinion bearing adjusting sleeve and is internally splined to receive the transmission output shaft On automatic transmission versions the pinion shaft extends forward beyond the pinion bearing adjusting sleeve and is externally splined to index with the transmission planetary carrier A seal is mounted in the pinion bearing adjusting sleeve to prevent lubricant from transferring between the rear axle and automatic transmission Because of its location between the engine and transmission the Corvair rear axle provides mounting elements usually incorporated on the transmission in conventional designs On manual transmission models the rear of the differential carrier mounts the shaft for the clutch release bearing whereas a stator shaft for the converter is carried by the automatic transmission rear axle The clutch release bearing shaft has a lip seal in the inner diameter to prevent lubricant from flowing rearward onto the clutch The stator shaft is externally splined and lip type seals are used at the contact of the pinion shaft and the inside diameter of the stator shaft to prevent transfer of lubricants A converter hub seal is mounted in the differential carrier adjacent to the stator shaft to prevent loss of automatic transmission fluid Both the clutch release bearing shaft and the stator shaft use an O ring seal at their mating surface with the differential carrier AINTENANCE CAUTION Under no circumstances should lubricant containing active sulphur be used in the Corvair axle Universal Joints Universal joints should be disassembled inspected and repacked every 25 000 miles or oftener unless under extreme dust conditions HUB NUTS For safety s sake the four wheel mounting nuts should be periodically checked for tightness