Slides. Rear Axle RTS2370A. Texto[1]

Rear axle RTS2370ADesign and Function

Student booklet

Aftermarket TrainingGT140001A

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RTS2370AThis training package describes the rear axle’sdesign and function. Service operations andthe use of special tools are described in Volvo’sservice literature.

Contents

1 General, tandem rear axle RTS2370A ...... 3

2 Type plate .................................................. 5

3 Tandem rear axle RTS2370A .................... 6

4 Final drives, front/rear................................ 7

5 Gear sets, front/rear .................................. 8

6 Differential ................................................. 9

7 Transfer gear ............................................. 10

8 Transfer gear differential lock .................... 11

9 Wheel differentiallock ................................ 12

10 Driveshafts .............................................. 13

11 Wheel bearings ....................................... 14

12 Maintenance ............................................ 15


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1. General, tandem rear axle RTS2370ARTS2370A is a tandem rear axle that consists of two single reduction gears of hypoid type and atransfer gear that is fitted to the first rear final drive.This rear axle is intended for use in heavy and demanding haulage operations both on good roadsand on poor road conditions. Drive to two axles means that extremely high traction can betransferred to the road surface, since the total axle pressure is high. This promotes excellent get-you-there ability, and also results in more uniform tyre wear between the front and rear axles.

RTS2370A is equipped with three differential locks, one each for the front and rear axle, and onefor the transfer gear. This guarantees excellent traction when the road surface is slippery andoffers poor grip.

RTS2370A is the type designation of this tandem rear axle. R = Rear axle T = Tandem S = Single reduction gear23 = Max bogie pressure 23,000kg70 = Max gross combination weight 70,000kg A = Version


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Notes:..........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

Specifications:

Make MeritorType designation RTS2370AType:Final drive Single reduction, Hypoid type, DTS35A front, DSS35A rearTransfer gear Cylindrical gearCrown wheel, diameter 401-417mmDriveshafts, diameter 53 mmMax engine torque 3100 NmMax bogie pressure 23,000 kgMax gross combination weight 70,000 kg

PAGE 4.Weight including driveshafts, hubs and drum brakes (with leaf springs):Front axle 793 kgRear axle 694 kg

Weight including driveshafts, hubs and disc brakes (with air suspension):Front axle 751 kgRear axle 639 kg

Oil-change volume:Front axle 20 litresRear axle 14 litres

Ratios : 2.43:1, 2.57:1, 2.83:1, 3.09:1, 3.40:1, 3.78:1, 4.13:1, 4.50:1, 5.14:1,(5.67:1. production start 0335 for the FL6)The transfer gear has a ratio of 1:1.


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2. Type plateThe rear axle is made by Meritor and is designated RTS2370A.

The type plate consists of the following markings:

COMPONENT = component designationDIFF. CARRIER/RATIO= final drive/ratioSERVICE CATEGORY = service categoryPART NO REAR AXLE = Volvo’s part numberDIFF. ASSY = Volvo’s part numberFABR. NO DIFF. ASSY = date of manufactureID = Internal factory number

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3. Tandem rear axle RTS2370ATandem rear axle RTS2370A consists of two rear axles with the following main components;

The first rear axle consists of:1. Rear axle casing2. Final drive with transfer gear3. Differential locks (transfer gear, differential lock and wheel differential lock).4. Driveshafts5. Output shaft

The second rear axle consists of:6. Rear axle casing7. Final drive8. Wheel differential lock9. DriveshaftsThe rear axle casings are cast in nodular iron.

Notes:...........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................


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4. Final drives, front/rearBoth the final drives (gear sets) are of hypoid type, which means that the pinion’s centre line isoffset in relation to the crown wheel’s centre line.This design allows more gear teeth to be in mesh at the same time, thus distributing the powerover several teeth. The result is a strong gear characterised by quiet operation and highdependability.

The crown wheel and pinion are matched to each other and cannot be replaced individually, butonly as a complete pair.In order to avoid the risk of accidentally separating the gear set, the crown wheel and pinion areboth marked with the same serial number.

The relevant components:

The front final drive consists of: gear set, transfer gear, differential, transfer gear differential lock,wheel differential lock.The rear final drive consists of: gear set, differential, wheel differential lock.

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5. Gear set, front/rearThe gear set consists of the pinion and crown wheel. The crown wheel is attached to the differen-tial.

A: The front pinion is supported by two conical roller-bearings.Adjustment of the pinion’s position is done with shims between the inner bearing’s outer ring andthe final drive housing.

B: The front pinion is supported in the pinion bearing sleeve (consisting of two conical roller-bearings).The bearings are pre-fitted and cannot be replaced separately since they are unit bearings. Behindthe pinion gear there is also a roller-bearing to handle radial forces. Adjustment of this pinion’sposition is also done with shims, between the pinion bearing sleeve and the final drive housing.

The correct pinion pre-tension is achieved as follows:Front pinion: with spacer sleeve and correct tightening torque.Rear pinion: correct tightening torque for the pinion nut.

Correct pre-tension on the rear pinion owing to the unit bearing = checked and fixed.Notes:............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................


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6. DifferentialThe purpose of the differential is to distribute torque and speed between the driven wheels and atthe same time maintain overall tractive power. This is necessary since the outer wheel has alonger distance to travel in a curve than the inner wheel. The outer wheel must therefore rotatefaster than the inner wheel.

The differential is fitted in the differential housing and consists of four small conical gears, differen-tial gears that are fitted to the spider. Two counter-rotating larger conical differential gears meshwith the four small gears, each linked with its respective driveshaft.

When the vehicle is driving straight ahead, the small gears in the differential are at a standstill andboth the driven wheels rotate at the same speed. When taking a curve, when the inner wheelrotates more slowly, the small wheels start rotating on the spider. Through this rotation, the speedreduction of the inner wheel is taken up and transferred to the outer wheel, which responds with acorresponding increase in speed.

The differential is supported with two conical bearings. The purpose of the adjustment screws isto create the correct pre-tension on the differential bearings and to give the gear set the correcttooth flank clearance.Notes:............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................


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7. Transfer gear1. Input shaft 3. Output shaft2. The transfer gear’s differential 4. Cylindrical gear

The forward final drive is equipped with a transfer gear. It has the task of distributing drive betweenthe two rear axles.

Power from the gearbox goes from the transfer gear’s input shaft via the transfer gear’s differen-tial to the output shaft which drives the second rear axle via a short propeller shaft.Power to the first rear axle goes via a cylindrical gear.

The path of the power: pinion, crown wheel, differential spider, via the small differential gears, on tothe large differential gears and then to the driveshafts, before finally going to the wheel.

Anteckningar:......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................


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8. Transfer gear, differential lockThe transfer gear is equipped with a differential lock to permit the same rotation speed on the rearaxles. The differential lock is operated via a two-stage switch on the instrument panel.

When the switch is pressed to its first position, the transfer gear differential lock is engaged,linking the two rear axles to each other. A symbol comes on in the instrument panel to indicatewhen the transfer gear differential lock is activated.

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Each rear axle has a wheel differential lock on the right driveshaft to ensure the same rotationspeed for the driveshafts on each respective rear axle.When one wheel slips, for instance on a slippery road surface, it is possible to disengage thedifferential by linking the driveshafts to each other with a differential lock, locking one driveshaft tothe differential housing. When the wheel differential lock is engaged, a symbol appears in theinstrument panel.

The locks consist of a claw coupling made of hardened steel which is manoeuvred by com-pressed air. When all the differential locks are engaged, all the driven wheels are forced to rotateat the same speed.

Notes:......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

9. Wheel, differential lock


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10. DriveshaftsThe driveshafts are of the fully unloaded type, that is to say the axles do not carry any of thevehicle’s weight; instead, their only job is to transfer rotating movement/torque from the final driveto the driven wheels.

The inner ends of the driveshafts are equipped with splines for linking up to the large differentialgears in the final drive. The outer ends feature a flange for fitting to the hub. In addition, the right-side driveshaft is equipped with an additional set of splines for the wheel differential lock’sconnecting flange.

The driveshafts for the first and second rear axle are of different lengths; do n´t mix them duringinstallation.

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11. Wheel bearingsThe wheel bearings are maintenance-free unit bearings. They consist of conical roller-bearingsthat are lubricated for life from the factory and fitted with sturdy seals.

The wheel hub and its bearing are fitted and removed as a single unit, which makes the processmuch more convenient.Bearing play is checked by inserting a metal bar in the wheel’s lightening holes and using the baras a lever. Normally, the bearings should be pre-tensioned, so there should not be any measurableplay in the wheel bearing. If any play is registered in the bearing, it should be measured with a dialgauge.

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12. MaintenanceThe rear axle has long service intervals that contribute to low operating costs.With Volvo-approved synthetic oil, oil is changed after max 400,000 km or every three years.

When overhauling follow the instructions i service bulletins;SB 465-73, front final driveSB 465-78, rear final drive

At service, check the sealing around the rear axle housing – pay special attention to any signs ofleakage.

Notes:........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

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Slides. Rear Axle RTS2370A. Texto[1]