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macmacs

Need Help Replacing Ls400 Transmission

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The tranny in our LS died, and I'm looking at a couple of different replacement transmissions.

First is from a 1992 SC400, and the second is from a 1992 LS400. Would they fit my 1990 LS400? I believe the two are identical, but I may have read that the '92 has different solenoid plugs?

Any help is appreciated!

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The tranny in our LS died, and I'm looking at a couple of different replacement transmissions.

First is from a 1992 SC400, and the second is from a 1992 LS400. Would they fit my 1990 LS400? I believe the two are identical, but I may have read that the '92 has different solenoid plugs?

Any help is appreciated!

macmacs,

I am pretty new to this forum, so you may want to check with someone more knowledgeable; however, I believe that the '92 LS400 came standard with the A341e transmission, which has 4 solenoids - 1and 2 control the gears, 3 and 4 moderate the shifting for shock, smoothness etc. The A341e is supposed to be a bit different from the A340, and was used in several different models, including the Volvo 960, SC400, and some SUVs. I believe there are some lists floating around which indicate the vehicles outfitted with the A341e.

HTH

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CAnt really comment on the years/ difference but i know that most junkyards will either know or point you in the right direction.

Lenore you just saved me about $1000. I really cannot thank you enough!!!

Strangely enuff i don't visit the site much since my tranny died, so thanks to everyone.

Macmacs here is some info on the trannsmission. i have more like the gear tooth contact patterns and such. PM me if you need more:

AUTO TRANS DIAGNOSIS - A-340E/F/H & A-341E

1990 Lexus LS 400

AUTOMATIC TRANSMISSIONS

Toyota A-340E/F/H & A-341E Electronic Controls

APPLICATION

APPLICATION TABLE

Vehicle Application Transmission Mod

Lexus

1990 LS400 ...................................... A-341E

Toyota

1988-90 Cressida ................................ A-340E

1990 Pickup (4WD) ............................... A-340F

1988-90 Pickup (4WD) ............................ A-340H

1988-90 Supra ................................... A-340E

1990 4Runner (2WD) .............................. A-340E

1990 4Runner (4WD) .............................. A-340F

1988-90 4Runner (4WD) ........................... A-340H

􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀􀀀

DESCRIPTION

The center of the Electronically Controlled Transmission/

Transaxle (ECT) is the Electronic Controlled Unit (ECU). The ECU

receives information from various sensors and switches. Based on

information received, the ECU generates output signals to control

transmission operation. The ECU system controls shift points and

operation of lock-up clutch. The A-341E has a self-diagnosis function

which diagnoses and notifies of a malfunction in the electronically

controlled components. A failsafe function enables continuous vehicle

operation even when an electronic circuit malfunction has occurred.

The fail-safe feature controls solenoid valve back-up, speed sensor

back-up and manual operation functions.

OPERATION

* PLEASE READ THIS FIRST *

The engine control system consists of an engine ECU, sensors,

switches and solenoids. In order for the engine ECU to perform

properly, it must be kept constantly informed of engine operating

conditions. It is the task of the sensors to supply the engine ECU,

via electrical signals, with specific information required to

determine engine operating conditions. The engine ECU will then send

electrical signals to the ECT ECU to control shift timing, lock-up

timing, transfer shift timing (if equipped), self-diagnostic system,

fluid temperature warning system and backup system. Individual

component operation is as follows.

NOTE: Unless otherwise specified, references in this article to ECU

refer to the ECT ECU.

ECU INPUT SENSORS

Throttle Position (TP) Sensor

The TP sensor is mounted on side of throttle body. The TP

sensor senses throttle movement and position, and transmits an

electrical signal to ECU. This signal determines gear shifting points.

Vehicle Speed Sensor (VSS)

This signal is picked up from a rotor on the output shaft and

informs the ECU of road speed. The ECU uses sensor signals to control

shift points and lock-up clutch operation.

Transfer Shift Position Switch (TSPS)

The switch signals the ECU that transfer shift lever has been

shifted into "L4". When switch contact points are open, the ECU

detects the lever is in "H2" or "H4" position,

Pattern Select Switch (PSS)

2 shift schedules are programmed into ECU: "Power" and

"Normal" modes. The mode used by the ECU is determined by setting

driving pattern select switch.

Neutral Start Switch (NSS)

The neutral start switch signals the ECU range selector lever

position. Switch contains contacts for both starts; control circuit

and shift position indicator. The ECU uses signals from "2" and "L"

range.

Brake Light Switch (BLS)

The brake light switch signals the ECU whenever brakes are

applied. This signals the ECU whenever brakes are applied. This

signals the ECU to disengage torque converter lock-up clutch.

OD Main Switch (ODMS)

This switch causes transmission to shift in and out of

overdrive. When OD main switch is "ON", current from battery flows to

ECU, causing transmission to be OD enabled. When OD main switch is

turned off, current from the battery flows to ground.

Water Temperature Sensor (WTS)

The sensor monitors engine coolant temperature. A signal is

transmitted to ECU throughout entire range of operating temperatures.

Fluid Temperature Sensor (FTS)

The fluid temperature sensor sends a signal to ECU that

varies with transmission fluid temperatures.

Cruise Control Sensor (CCS)

This sensor signals a Cruise Control ECU which prevents

transmission from shifting into OD and prohibits lockup control when

vehicle speed drops below the drive set speed parameters.

Kickdown Switch (KS)

This switch signals the ECU if the accelerator pedal is

depressed beyond the full throttle valve opening position.

Engine Speed Sensor (ESS)

The engine speed sensor indicates engine RPM and sends a

signal to the ECU.

OD Direct Clutch Speed Sensor (ODDCSS)

The sensor senses the input shaft speed from 1-3 gear.

The whole file is 2.14MB so i couldn't upload it but

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