Description and operating principle of iB5 (Focus 1)

General appearance

Pos.	Spare Part No	Name
1		Clutch slave cylinder
2		Gearbox breather
3		Primary shaft
4		Secondary shaft
5		Differential

The manual transmission in the iB5 drive axle unit used in the Focus is a so-called "two-shaft gearbox". Its design has been modified and now it uses a cable drive mechanism for the first time.

The aluminum gearbox housing consists of two sections. The housing rigidity is increased by including reinforcing ribbing in its design. The housing sections are supplied in pairs and cannot be replaced separately. The clutch has a hydraulic drive.

In a two-shaft gearbox, the gears of all gears are in constant engagement (except for the reverse gear). In each gear, the required gear ratio is provided by a pair of gears.



When reverse gear is selected, the direction of rotation of the secondary shaft is changed by using an intermediate gear.

All gears have a circular tooth, are synchronized (except for the reverse gear) and are mounted on plain bearings.

The first and second gears have double synchronizers.

The manual gearbox in the block with the iB5 drive axle is filled with 2.5 liters of synthetic transmission fluid, specification WSD-M2C200-C. The filling level is 10-15 mm below the lower edge of the inspection hole. There is no need to change the transmission fluid.

Elements of a manual gearbox in a block with a leading axle iB5

Pos.	Spare Part No	Name
1		Quick coupling
2		Oil seal (access from outside)
3		Clutch slave cylinder with clutch release bearing (cannot be replaced separately)
4		Intermediate shaft of the front drive axle
5		Cylindrical spur gear
6		Three-leg joint body ("tripod")
7		Synchronizer 1/2 gear
8		Synchronizer 3/4 - th gear
9		5th gear synchronizer
10		Gearbox breather

In the neutral position, none of the gears are connected to the secondary shaft via the corresponding synchronizers. Primary torque is not transmitted to the differential.

Internal gear shift mechanism

Pos.	Spare Part No	Name
1		5th/Reverse Gear Selector Rod Guide Bushing
2		Gear selection lever
3		Gear shift stop bushing
4		Gear selector shaft locking mechanism
5		Gear selection shaft
6		Return spring for reverse gear selector lever
7		Reverse gear selection lever
8		Retaining ring
9		5th/Reverse Gear Selector Rod

Primary shaft

Pos.	Spare Part No	Name
1		Ball bearing
2		Primary shaft
3		Reverse intermediate gear
4		1st gear pinion
5		Reverse gear pinion
6		2nd gear pinion
7		3rd gear pinion
8		4th gear pinion
9		Retaining ring
10		5th gear pinion
11		Retaining ring

Secondary shaft

Pos.	Spare Part No	Name
1		Roller bearing
2		Secondary shaft
3		1st gear pinion
4		Inner ring of the synchronizer
5		Conical ring of the synchronizer
6		Outer synchronizer ring
7		Synchronizer 1/2 - th gear with reverse gear pinion
8		Retaining ring
9		Outer synchronizer ring
10		Conical ring of the synchronizer
11		Inner ring of the synchronizer
12		2nd gear pinion
13		Retaining half rings
14		Retaining ring
15		3rd gear pinion
16		3rd gear synchronizer ring
17		Synchronizer 3/4 - th gear
18		4th gear synchronizer ring
19		4th gear pinion
20		Ball bearing (sealed on both sides)
21		Retaining ring
22		5th gear pinion
23		5th gear synchronizer ring
24		5th gear synchronizer
25		Stop bar

Double synchronizer

Pos.	Spare Part No	Name
1		Gear
2		Inner ring of the synchronizer
3		Conical synchronizer ring
4		Outer synchronizer ring
5		Synchronizer hub

Double synchronizer

The first and second gears have double synchronizers. By using a second synchronizer ring, the effective synchronizer surface is significantly increased compared to a single synchronizer. Double synchronization provides a significant improvement in gear shift quality.

Double synchronizers include an inner synchronizer ring, a conical ring, an outer synchronizer ring and a synchronizer hub.

The conical surface of the gear is no longer used. Synchronization occurs through the use of synchronizer rings and a conical ring, which is attached to the gear.

Differential

The main elements of the differential include:

• Cylindrical spur gear
• Differential box with two tapered roller bearings
• Differential satellites
• Half-axle gears

The gearbox and differential are enclosed in a two-section aluminum housing, which has a flange mount to the engine. The drive axle half-shafts have splines.

Primary torque is transmitted to the differential via a spur gear that is bolted to the differential case.



The differential box contains differential satellites mounted on one axle, as well as axle gears that have a splined connection with the axle shafts of the front drive axle.

If the front wheels have different speeds (for example, when turning), the axle gears can move the differential pinions.

Neutral gear

Pos.	Spare Part No	Name
1		Primary shaft
2		Secondary shaft
3		Output gear

First gear

Pos.	Spare Part No	Name
1		Primary shaft
2		Secondary shaft
3		Output gear
4		1st gear pinion
5		Synchronizer 1/2 - th gear
6		1st gear pinion

Second gear

Pos.	Spare Part No	Name
1		Primary shaft
2		Secondary shaft
3		Output gear
4		Synchronizer 1/2 - th gear
5		2nd gear pinion
6		2nd gear pinion

Third gear

Pos.	Spare Part No	Name
1		Primary shaft
2		Secondary shaft
3		Output gear
4		3rd gear pinion
5		Synchronizer 3/4 - th gear
6		3rd gear pinion

Fourth gear

Pos.	Spare Part No	Name
1		Primary shaft
2		Secondary shaft
3		Output gear
4		Synchronizer 3/4 - th gear
5		4th gear pinion
6		4th gear pinion

Fifth gear

Pos.	Spare Part No	Name
1		Primary shaft
2		Secondary shaft
3		Output gear
4		5th gear pinion
5		5th gear synchronizer
6		5th gear pinion

Reverse gear

Pos.	Spare Part No	Name
1		Primary shaft
2		Secondary shaft
3		Output gear
4		Reverse gear pinion
5		Reverse gear pinion
6		Reverse intermediate gear

The reverse gear intermediate gear is driven by the primary shaft. Its purpose is to change the direction of rotation of the secondary shaft when reverse gear is engaged.

The intermediate reverse gear pinion is supported by a needle bearing located on the intermediate axle and a bearing block.

The gear selector lock mechanism and gear selector pin are secured to a bushing in the gear selector housing. They use a spring-loaded ball to hold the selected gear in engagement until another gear is selected.

The gear selector lock mechanism has three different positions.

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