Automatic Transmission DESCRIPTION
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SECTION AT AUTOMATIC DATSUN 2802 TRANSMISSION MODEL S30 SERIES DESCRlPTlDN ....................................... 2 HYDRAULIC CONTROL SYSTEM ...... AT- 4 REMOVAL AN0 INSTALLATION ......... AT43 MAJOR REPAIR OPERATION ............A T-36 TROUBLE DIAGNOSES AND ..............AT-48 ADJUSTMENT SERVICE DATA AND ........................... SPECIFICATIONS AT-59 SPECIAL SERVICE TOOLS ............... AT-62 NISSAN MOTOR CO., LTD. TOKYO, JAPAN Automatic Transmission DESCRIPTION The model 3N71B automatic trans- “2” - “2“ range provides performance mission is a fully automatic unit con. for driving on slippery surfaces. “2” sisting primarily of 3element hydrau- range can also he used for engine lic torque converter and two planetary braking. gear sets. Two multiple-disc clutches, a “2” range can be selected at any multiple-disc brake, a bacd brake and vehicle speed, and prevents the trans- a one way sprag clutch provide the mission from shifting out of second friction elements required to obtain gear. the desired function of the two plane- “1” ~ “I” range can be selected at AT057 tary gear sets. any vehicle speed and the transmission The two planetary gear sets give will shift to second gear and remain in Fig. AT-l Idenlificalio?t number three forward ratios and one reverse. second until vcliicle speed is reduced Changing of tlie gear ratios is fully to approximately 40 to SO km/h (25 automatic in relation to vehicle speed to 31 MPH). and engine torque input. Veliicle speed “I” range position prevents the Identifkation of number and engine manifold vacuuni signals transniissioti from shifting out of low are constantly fed to the transmission Arrangements: gear. This is particularly beneficial for to provide the proper gear ratio for See below. maintaining maximum cngine braking maximum efficiency and performance when continuous low gear operation is at all throttle openings. desirable. The model 3N71 B has six selector The torque converter assembly is of positions: P,R,N,D,2, I. welded construction and can not be Model code disassembled for service. “P’ - Park position positively locks the output shaft to the transmission I \\ JAPAN AUTOMATIC case by means of a locking pawl to TRANSMISSION CO.. LTD. prevent the vehicle from rulling in I Q,- either direction. I PODELI X2710 This position should be selected whenever the driver leaves the vehicle. FLUID RECOMMENDATION The engine may bc started in Park position. Use autoniatic transmission fluid having “DEXRON” identifications Unit number “R” - Reverse range enables the only in the 3N71B automatic transniis- vehicle to be operated in a reverse sion. direction. Number designation “N” - Neutral position enables the 4912345 engine to he started and run without IDENTIFICATION NUMBER driving the vehicle. Serial production nurnhei for the month “D” - Drive range is used for all Stamped position: - Month of production (X:Oct.. Y:Nov., 2: Dec.) normal driving conditions. The plate is attached to tlie right Drive range has tlirre gear ratios. Iiaih side uf transmission case as - Last fipure denoting the year (A.D.) from the starting ratio to direct drive. shown in Figure AT.1 AT-2 ____ _____ Automatic Transmission AT312 I Transmission case 11 Governor Tightening torque (T) of 2 Oilpump 12 Output shaft bolts and nuts kg-m (ft-lb) 3 Front clutch 13 Rear extension 4 to 5 (29 to 36) 4 Band brake 14 Oilpan @ T 14 to 16 (101 to 116) 5 Rear clutch 15 Control valve @IT T: 4.5 lo 5.5 (33 to 40) 6 Front planetary gear 16 Input shaft @ @I T: 0.6 to 0.8 (4.3 to 5.8) I Rear planetary gear 17 Torque converter 8 One-way clutch 18 Converter housing @ T 0.5 to 0.7 (3.6 to 5.1) T 2.0 to 2.5 (14 to 18) 9 Low & Reverse brake 19 Drive plate @ 1.3 to 1.8 (9.4 to 13.0) 10 Oil distributor @J T @ T 0.55 to 0.75 (4.0 to 5.4) @ T 0.25 to 0.35 (1.8 to 2.5) Fig. AT-2 Cross-sectional view uf:t.V7lB aalo~nalicfronsnaissioii AT-3 Automatic Transmission HYDRAULIC CONTROL SYSTEM CONTENTS FUNCTIONS OF HYDRAULIC CONTROL "P" RANGE (PARK) ..................... AT-14 UNIT AND VALVES ...................... AT- 4 "R" RANGE (REVERSE) .................. AT-16 OIL PUMP ............................. AT- 4 "N" RANGE (NEUTRAL) ................. AT-18 MANUAL LINKAGE ..................... AT- 4 "Dt" RANGE (LOW GEAR) .............. AT-20 VACUUM ,DIAPHRAGM .................. AT- 5 "D2" RANGE (2ND GEAFII . , , . , . , , . , , , . AT-22 DOWNSHIFT SOLENOID ................. AT- 5 "D3" RANGE (TOP GEAF:) ................ AT-24 GOVERNOR VALVE .................... AT- 5 "D" RANGE KICK-DOWN ................ AT-26 CONTROL VALVE ASSEMBLY ........... AT- 6 "2" RANGE (2ND GEAR1 ................. AT-28 HYDRAULIC SYSTEM AND "11" RANGE (LOW GEAR) ................ AT-30 MECHANICAL OPERATION ................ AT-13 "12" RANGE 12ND GEAF) ................ AT-32 FUNCTIONS OF tains an oil pump for packing up Oil solenoid. These parts work in conjunc- from the oil pan through the oil tion with valves in the valve body HYDRAULIC CONTROL strainer. A shift control is provided by assembly located in the base of the UNIT AND VALVES two centrifugally operated hydraulic transmiss:on. The valves regulate oil governors on the output shaft. vacuum pressure and direct it lo appropriate The hydraulic control system con- control diaphragm and downshift transmission components. Oil pump Control valve 71Torque converter Manual linkage Front clutch ~ Rear clutch Vacuum diaphragm Low and reverse brake Downshift solenoid Band brake Governor valve I1Lubrication OIL PUMP housing delivery port ~ Transmission MANUAL LINKAGE case delivery port - Lower body delivery port - Control valve line The hand lever motion (the hand The oil pump is the source of pressure circuit. lever is located in the driver's compart- control medium (i.e., oil) for the ment), mechanically transmitted from control system. the remote control linkage, is further The oil pump is of an internal, transmitted to the inner manual lever involute gear type. The drive sleeve is a in the transmission case from the range part of the torque converter pump selector lever in the right center por- impeller and serves to drive the pump tion of the transmission case through .inner gear with the drive sleeve direct- the manual shaft. The inner manual ly coupled with the engine operation. lever is thereby turned. The oil flows through the following A pin installed on the bottom of route: AT071 the inner manual lever slides the manu- Oil pan - Oil strainer (bottom of the al valve :spool of the control valve thus I Housing 4 1nncrgear positioning the spool opposite the control valve) - Control valve lower 2 Cover 5 Crescent body suction port -Transmission case 3 Outer gear appropriate select position. suction port - Pump housing suction The parking rod pin is held in thc Fig. AT-3 Oil pump groove on the top 01 lhc inncr milnual port - Pump gear space ~ Pump AT4 Automatic Transmission plate. The parking rod pin operates the vacuuni reaction increases since the rod at “P” range, and operates the flow velocity of niixture inside the mechanical lock system. intake manifold is slow. Contrarily, The above described manual shaft is when the engine speed increases and further equipped with an inhibitor the flow velocity of the mixture in- switch. A rotor inside the inhibitor creases or when the carburetor is switch rotates in response to each closed, the manifold negative pressure \ range. When tlie range is selected at increases (i.e., tends towards vacuum) AT089 “P” or “N”, the rotor closes the and the vacuum reaction is reduced. Fig. AT-6 Downshift solenoid starter magnet circuit so that the Thus, a signal to generate hydraulic engine can be started. When the range pressure perfectly suited to the engine is selected at “R”, the rotor closes the loading at the control valve is trans- GOVERNER VALVE back-up lamp circuit, and the back-up mitted from the vacuum diaphragm, The primary and secondary gover- lamp lights. and the most suitable timing for speed nor valves are installed separately on change and line pressure is obtained so the back of the oil distributor on the that the most proper torque capacity transmission output shaft. They op- is obtained against the transmitting erate at the same speed as that of the torque. output shaft. (that is, they operate at a speed in proportion to the vehicle speed.) The line pressure is applied to those valves as the input from the control valve, through the transmission case, rear flange and oil distributor. The governor pressure [in proportion to the output shaft speed (vehicle AT08J speed)] is led to the shift valve of the I Manual plate 3 Parkingrad AT088 control valve through the opposite 2 Inhibitor switch 4 Manual shalt route of tlie output. In this manner Fig. AT-5 Vacuum diaphragm speed change and line pressure are Fig. AT-4 Manual linkage controlled VACUUM DIAPHRAGM DOWNSHIFT SOLENOID The vacuum diaphragm is installed The downshift solenoid is of a Operation of secondary on the left center portion of the magnetic type installed on the left rear governor valve transmission case. The internal con- portion of the transmission case. When The secondary valve is a control struction of the vacuum diaphragm is a driver requires accelerating power valve which receives line pressure (1) as follows: and depresses the accelerator pedal and controls the governor pressure. down stopper, kickdown A rubber diaphragm forms a parti- lo tlie a When the manual valve is selected switch located in the middle of the tion in the center. The engine intake at “D’,“2” or “1” range, line pressure manifold negative pressure is led accelerator link is depressed by a push is applied to the ring shaped area of through a vacuum tube and spring rod, the kickdown switch closes, cur- this valve from circuit (I), and this rent flows to solenoid.