Description - Honda Prelude 1993 Service Manual

Description
The Automatic Transmission is a combination of a 3-element torque converter 8nd tripls-shaft electronicaly controllod
sutom8tic transmission which provides 4 speeds forward and 1 speed reverse. The entire unit is poshioned in line with the
engrne.
Torqug Convarter, G6ars and Clutches
The torque converter consists of a pump, turbine and stator Sssembled in a singls unh,
Thsy are connected to the engine crankshsJt so they turn togeth€r as a unh as the engine turns. Around th€ outside of the
torque conv€rter is a ring gear which meshes with the stsrtel pinion wh6n the engin€ ig b€ing st8rt6d. The antir€ torque
converter assembly serves as a flywheel while transmitting power to the transmission mainshaft.
The transmission has three psrsllel shatts: the mainshatt, the countershaft, and ths secondary shaft. The mainshaft is in line
with the engine crankshsJt.
The mainshaft includes the clutches tor 3rd. snd 4th, and gears for 3rd, 4th, R6vsrse and ldlor (Rsverse gesr is intogralwith 4th
gear).
The countershaft includes the lst-hold clutch and gears for 2nd, 3rd, 4th, Reverse, lst End Hler.
Th6 secondary shaft includes the 1st and 2nd clutches, and gesrs tor 2nd, 1st and Hler.
The 4th 8nd reverse g€ars can be locked to the countershaft 8t its center, providing 4th gear or Reverse, depending on which
w8v the selector is moved.
Ths gears on the msinshaJt are in constsnt m€sh with thosa on ths countershatt and the secondary shaft. When certain
combinations of gears illbe lMsDl9giol
lre etglged by the clutches, power is tr8nsmitted from the mainshalt to the
countershaft to pro"ia" O.-l,f-O"-l,f
, T
and@oosirions.
Eleqtronic Control
The electronic control system consists of the Transmission Control Module {TCM), sensors, and 4 solonoid valves. Shifting 8nd
lock-up are €l6ctronicslly controlled for comtonable driving under allconditions,
The TCM is located b8low the dsshboard, behind the right sido kick panol on the psss6ng6r's sids.
Hydr8ullc Conilol
The vslve bodies include the main valve body. secondary vafue body, servo body, regulator vafue body, throttl€ vsve body and
lst/2nd accumulatof body. They 8re bohed to the torque converter housing as an assembly,
The main vslve body contains the msnual valve, 1-2 shift valvs, 2-3 shift valvs, coolel relief valve, lock-up shift vafue, lock-up
control valve, 3-2 kick-down valve, modul8tor vatue. CPC valve and oil pump gears,
The secondary valvo body includes the 4th exhaust valve, 3rd kick-down v8lve,3-4 shift vafu€, servo control vslve, orific€
controlvalve and the 2nd otifice controlvalv6.
The servo body contains the accumulator pistons 8nd servo valve. The rogulEtor vafus body contains the roguhtor valve,
torque converter check valve, and lock-up timing v8lve. The throttle valve body contains ths throttle valve B and relief valve.
Fluid from the regulator passes through the manusl vatve to the various control valves.
The clutches receive oiltrom their respective feed pip6s or internal hydraulic circuit,
Shlft Control Mechanism
Input from various sensors located throughout the car determin€s which shift control solsnoid valve the TCM will activate.
Activating 8 shiJt control solenoid valve chsnges modulator pressure, causing I shtft valve to move. This pressurizes a line to
one of the clutches, engaging that clutch and its corresponding gear,
Lock-up Machanlsm
In L91l position, in 2nd, 3rd and 4th. and I D3 | position in 3rd, pressurized fluid is drained from the back of the torque converter
througir an oil pass8ge, csusing the lock-up piston to be heH agsinst the torqus converter cover. As this takes phcs, th€
mainshaft rotates 8t the same speed as the engine crankshaft. Together with hydrsulic control, the TCM optimizes the timing of
the lock-up mechanism.
The lock-up vatues controlthe range of lock-up according to lock-up controlsolenoid valves A and B, and throttle valve B.
When lock-up controlsolsnoid vslves A and B activate, modulator pressure changes. Lock-up controlsolenoid vslv€s A and B
are mounted on the torque converter housing. and are controlled by the TCM,
lcont'dl
14 -3