Elements of automatic transmission Ford A 4 LD
1 - oil pan, 2 - oil receiver, 3 - gaskets, 4 - reverse gear drive, 5 - hydrokinetic control unit, 6 - cover and seals, 7 - forward gear drive, 8 - middle gear drive, 9 - vacuum regulator, 10 - acceleration valve, 11 - safety switch, 12 - locking ratchet and parking lock mechanism, 13 - sealing ring, 14 - rear gearbox housing, 14a - gasket, 15 - parking lock mechanism latch, 16 - secondary shaft, 17 - regulator, 18 - Viton sealing rings, 19 - regulator hub with parking lock mechanism gear, 20 - ring, 21 - middle gearbox housing, 22 - oil pan gasket, 23 - rear clutch, 24 - ring, 25 - band brakes, 26 - brake drum, 27 - rear planetary gear, 28 - retaining ring, 28a - gasket, 29 - sun gears, 30 - front planetary gear housing, 31 - front planetary gear, 32 - needle bearing, 32a and 33 - rings, 34 - front clutch, 35 - sealing rings, 36 - direct drive multi-plate clutch, 37 - thrust lining, 37a - sealing rings, 38 - middle planetary gear housing, 39 - thrust lining, 40 - middle planetary gear, 41 - one-way clutch, 41a - needle bearing, 42 - multi-plate clutch, 43 - gasket, 44 - thrust lining, 45 - oil pump, 45a - sealing rings, 45b - oil pump shaft sealing ring, 46 - oil pump gear, 47 - intermediate plate, 47a - intermediate plate gasket, 48 - hydrokinetic transmission housing, 48a - gasket, 49 - output shaft, 50 - hydrokinetic transmission
Since the 1985 model, a version of cars equipped with an automatic four-speed gearbox Ford A 4 LD has been introduced. This gearbox is equipped with a clutch locking hydrokinetic transmission. Its first three gears correspond to the gears of the three-speed automatic gearbox Ford C 3, and the 4th gear is an overdrive (has a gear ratio that increases the number of revolutions).
Kick-down mechanism cable
Initially, in the Ford A 4 LD automatic transmissions, the kick-down mechanism was controlled mechanically (see Fig. Adjusting the kick-down mechanism cable in version 1).
Since May 1986 (manufacturing date code "GJ") the kick-down mechanism has been controlled by a solenoid valve, which provides more precise gear reduction.
Differences between the C3 and A4 LD automatic transmissions
In the four-speed gearbox A 4 LD after the 3rd and 4th gears are engaged, the hydrokinetic transmission is locked, which reduces the heating of the oil in the gearbox, as well as the fuel consumption of the engine. The fourth gear has an increasing gear ratio, which is the reason why the engine speed is 25% lower than in the 3rd (direct) gear at the same speed.
Pressing the accelerator pedal all the way down (kick-down) causes automatic gear shifting to 3rd. This allows for greater acceleration and maximum speed.
Technical data
| Brand and type | Ford A 4 LD |
| Hydrokinetic transmission | Trilock with locking clutch |
| Hydrokinetic gear number | 2,8 |
| Oil radiator | tubular |
Control parameters
Control oil pressure (kPa)
| Gear shift lever position | Idle pressure | Pressure* at 1600 rpm |
| "R" | 450 – 550 | 1850 – 2200 |
| "P" and "N" | 350 – 430 | – |
| "DE"; "D"; "2" and "1" | 350 – 430 | 1100 – 1300 |
* Pressure during engine overload test
The engine speed during overload testing is 2000–2900 rpm.
Speeds at which gear shifting occurs
| Pedal position | Gear shifting | |||
| accelerator | 1 – 2 | 2 – 3 | 3 – 2 | 2 – 1 |
| The accelerator pedal is pressed all the way down | 5800±200 rpm | 5800±200 rpm | 75 km/h | – |
| The accelerator pedal is pressed 3/4 | – | – | 50 km/h | – |
| The accelerator pedal is not pressed | – | – | 90 km/h (lever in position "2") | between 60 (lever in position "1") |
| The speed numbers given in the table apply to the engine. | ||||
Gear numbers
Broadcast | Gear number | Total number of transmission with main transmission with number | |
| 3,62* | 3,38** | ||
| 1 | 2,474 | 8,96 | 8,36 |
| 2 | 1,474 | 5,34 | 4,98 |
| 3 | 1,000 | 3,62 | 3,38 |
| 4 | 0,749 | 2,71 | 2,53 |
| Reverse | 2,111 | 7,64 | 7.14 |
* Ford Sierra 1.8 (carbureted engine) and 2.0i (fuel injected engine.
** In Ford Sierra 2.0 vehicles (carburetor engine).
Lubrication
| Amount of oil | 8.5 dm³ |
| Type | automatic transmission oil SQM 2C 9010 A (CJ transmission oil) |
Tightening moments
| Hydrokinetic transmission housing to the engine | 30 – 37 Nm |
| Hydrokinetic transmission housing to automatic transmission front housing | 36 – 53 Nm |
| Hydraulic control unit | 9 – 13 Nm |
| Brake band tension adjustment bolt lock nut | 47 – 61 Nm |
| Intermediate holder bolt | 27 – 40 Nm |
[The original article can be viewed on the portal: FORDBOOK.RU]