Publi s hed: 11-May-2011
Driveshaft -
General SpecificationItemSpecification
TypeThree piece dri ves haft , incorporat ing centre bearings , CV joints , a s waged front s ect ion, and longpl unge double offset joint at the rear of the front s ect ionFixed const antvelocit y joi ntFront
Plunging cons tantvelocit y joi ntRear
Long plunge doubl eoffs et jointRear of front s ect ion
Torque Specifications
DescriptionNmlb-ft
CV joint s upport bracket bolt s t o floor2518Driveshaft to power t rans fer unit Torx bol ts *4030
Driveshaft to rear different ial pinion flange Torx bol ts *4030
CV joint s upport bracket bolt s t o t o CV joint2418* New nuts/bolts must be fitted
Publ is hed: 23-Sep-2011
Rear Drive Axle/Differential -
LubricationDescriptionLubricantCapacity (liters/pints/US quarts)
Haldex controlled coupli ngSt at oil SL01-301. Land Rover Part No LR0031360.65/1.1/0.69
Rear drive axl e/different ialCas trol Axl e EPX 80W -90. Land Rover Part No LR0031560.7/1.2/0.74
General Specification
ItemSpecificationDi fferenti al t ypeLow offset hypoi d s piral bevel des ign
Rati o2.58:1
Electronic t orque managed (ETM) rangeUp to 1500 Nm (1106 lbf.ft)
Torque SpecificationsDescriptionNmlb-ft
Acti ve on-demand coupl ing module64
Acti ve on-demand coupl ing t o different ial2418Acti ve on-demand oil pump64
Driveshaft to the rear flange*4030
Rear different ial front bus h retaini ng bol ts *175129Rear different ial ins ulator t o t he rear different ial2518
Rear different ial rear bush ret ai ning bolt s *11081
Rear different ial support bracket2518Rear drive axl e/different ial pinion fl ange nut *13096
Rear drive axl e/different ial fl uid drain pl ug3526
Rear drive axl e/different ial fl uid fil ler plug3526* New nuts/bolts must be fitted
Vehicles from 2009MY are fit ted wit h a modi fied des ign of t he acti ve on-demand coupling, known as the generat ion 4 uni t.The new acti ve on-demand coupl ing has desi gn improvement changes over t he previous generati on 3 coupl ing whi ch gi vet he foll owing advant ages:
Reduced bas e t orque at high different ial s peedTorque acti vat ion i ndependent of different ial s peedAccurat e t orque l imi terEnergy s tored in accumulat orLower max current cons umpt ionFast er res pons e.
DIFFERENTIAL
The different ial unit i s a l ow-offs et -hypoid spi ral-bevel des ign, bas ed on a 167mm crown wheel geared t o deli ver a rat io of2.58:1. The des ign of t he different ial gears and t he 4 mount ings t hat control t he t orque react ion of t he uni t wit hin the rears ubframe, provi de a different ial unit of excel lent efficiency and refinement.
The t orque delivered to the di fferenti al i s cont rol led by t he acti ve on-demand coupli ng, mount ed int o t he voi d at t he frontof the di fferenti al's cas t-alumi num casi ng, whi ch als o provi des t he oil reservoi r for t he coupli ng.
ACTIVE ON-DEMAND COUPLING
Acti ve On-demand Coupl ing
• NOTE: Generati on 3 coupling shown.
Not s ens it ive to brake tes ti ng on a chas si s dynamomet er.
Generati on 4 Acti ve On-Demand Coupli ng - Vehicles from 2009MY
The generati on 4 coupl ing does not have the di fferenti al s peed dri ven pump used on the previ ous generat ion 3coupl ing, but i s fit ted wi th a bigger capacit y electrically operated axial pump and a hi gh pres s ure accumul ator.The proport ional throt t le valve and press ure s ens or on t he generat ion 3 coupli ng is replaced wit h a proport ionalpres s ure reducing val ve.The t orque li mit er pres sure reducing valve on the generat ion 3 coupli ng is replaced by an electroni c cont rol valveand cont rol ling software.
The generati on 4 acti ve on-demand coupli ng gives t he fol lowing improvements over t he previous generati on 3 coupl ing:
Reduced bas e t orque at high different ial s peedsTorque acti vat ion i s now i ndependent of different ial s peedAccurat e t orque l imi ter cont rolEnergy s tored in hi gh pres s ure accumul ator givi ng a low maximum current consumpt ion of t he electric pump andfas t er res pons e.
Control Module - G eneration 3 and 4 Couplings
The cont rol module, at tached to the cas ing of t he act ive on-demand coupling, forms a s ingle unit wit h t he cont rolvalve/axial s ol enoi d. By anal yzi ng informat ion from other vehi cl e modules and s ensors t he cont rol module regul ates t heaxial sol enoi d t o cont rol t he hydraul ic flui d pres s ure s uppl ied t o t he clut ch pl ates. Some of t he modul es and s ens ors thecont rol module communi cat es wit h are li s ted below:
Hardwi red:- Control valve / axi al s olenoid- Electric hydrauli c pump- Oi l press ure and temperat ure sens orHigh speed CAN (cont rol ler area net work):- Engine cont rol module- Anti -l ock brake s ys t em / t racti on cont rol module- Tracti on res ponse swit ch- Y aw rate sens or- Steering wheel rot at ion sens or
The axial sol enoi d cons t ant ly adjust s t he cont rol valve output us ing a Pul se W i dt h Modulat ion (PW M) s i gnal. The flui dpres s ure deli vered t o t he cl utch plat es determines t he amount of t orque t hat is delivered t o t he rear axl e.
The act ive on-demand coupli ng has int egrated oi l press ure and temperature s ens ors to enable the control modul e t oaccurat ely manage t he t orque t ransfer under all environment al and operat ing condit ions . Usi ng thes e s ignals the controlmodule will us e s t rategi es to protect the coupli ng from overheati ng; in extreme cas es to protect t he coupli ng from damaget he coupli ng wil l dis engage i f the t emperat ure of t he hydraul ic flui d exceeds 105°C. The coupl ing wi ll ret urn to normalfuncti onal it y when t he temperat ure fall s below 101°C.
The cont rol module has an int egrated di agnos ti cs sys tem, whi ch cons tant ly moni tors the act ive on-demand couplings ys t em as wel l as it s input and output s ignals . If t he control modul e detects a fault a Diagnost ic Troubl e Code (DTC) i ss tored. The DTC is acces s ed usi ng t he Land Rover approved di agnos t ic s yst em.
Electric Hydraulic Pump
W hen negoti ati ng very low frict ion s urfaces s uch as wet gras s , snow or i ce; i nit ial wheel -s pin can cut i nt o t he s urface andreduce gri p. W it h a re-act ive on-demand coupl ing, almos t 60 degrees of wheel rotat ion woul d occur before torque could bet ransmit ted t hrough t he coupl ing.
On Generat ion 3 coupli ngs , t o count eract thi s Land Rover devel oped a uni que high-pres s ure pre-charge faci li ty whi chenergizes t he hydraul ic circui t as s oon as the engi ne is s t art ed. Es s ent ial ly an el ect ri cal ly operat ed hydraul ic pump wasdesi gned to maintai n a pot ent ial of 500 Nm (369 l b ft ) of t orque pres s ure wi thi n the coupli ng. (This pre-charge t orquecapacit y has been increas ed to 1500Nm (1106 l b ft ) for t he Generat ion 4 coupli ng.)
Vehicles fit ted wi th Terrai n Res pons e als o add furt her benefi ts by varying t he level of pre-charge t o deli ver opti mumt racti on over a range of di fferent t errai n s urfaces . The level of pre-charge is varied dependi ng on t he part icul ar terrainres ponse mode, for exampl e:
Terrai n respons e in 'Speci al Programs Off' mode as common wit h vehi cl es wit hout terrain res pons e, the coupli ng isprogrammed t o transmit 500 Nm 369 lb ft of t orque on Generat ion 3 couplings and 1500 Nm (1106 l b ft) of t orqueon Generat ion 4 couplings t o t he rear axle when the vehicle moves from res t i n a s t raight l ine. Thi s s trategymi ni mi zes t ract ion l os s from a s t andi ng-s tart regardles s of t he terrain. W hen the vehicle accelerat es the pres surein the coupling is decreas ed to improve fuel economy.The abili ty to sens e t he s teeri ng angl e all ows t he coupli ng t o be programmed t o provide no torque trans fer t hrought he coupli ng. This prevent s t he coupli ng locking when t he vehicle i s maneuvring at low s peeds and acute s teeri ngangl es.In 'Grass / Gravel / Snow' mode t he coupl ing i s programmed to maint ai n i ts pre-charge s t at e unt il much highers peeds are obtained. The s ame applies even i f the vehicle is t raveli ng at low speeds and acut e s t eering angles , ast racti on takes precedence over coupli ng lock-up on l ow-fri ct ion s urfaces .
For addit ional informat ion, refer t o: Ride and Handli ng Opti mizat ion (204-06 Ride and Handli ng Opt imi zat ion, Descripti onand Operat ion).
Mechanical Hydraulic Pump - Generation 3 Couplings - Vehicles up to 2009MY
The dri ves haft i s att ached t o t he coupl ing's front clut ch pl ate as s embly (i nput ), with the rear cl ut ch plat e as sembl yconnected t o t he different ial pini on (out put ). A s was h-pl ate wit h 6 hydrauli c rol lers is al so att ached t o t he different ialpinion. W hen there is no s peed difference bet ween the coupling's input and out put, the rol lers do not funct ion.
However, when the front and rear axl es st art t o rotat e at different s peeds , t he s wash-pl ate rot at es rel ati ve to the roll erswhich generat es the hydrauli c pres s ure. Thi s pres s ure i s us ed to force the opposi ng clut ch pl ates t oget her, i ncreas ing thet ransmis s ion of t orque t o the rear axl e. As the di fference in axl e s peed i ncreases the hydrauli c pres sure pushes t he clut chplat es further together t o increas e t he t orque to the rear axl e.
A control val ve/axi al s olenoid cont rols the amount of pres s ure appli ed to the clut ch plat es , and hence the amount oft orque transmit ted t o t he rear wheels . Clos e manufact uring t olerances and except ional ly low component wear ens uret orque cont rol remai ns accurat e t hroughout t he vehi cl e's l ife.
Mechanical Hydraulic Pump - Generation 4 Couplings - Vehicles from 2009MY
The Generati on 4 coupl ing does not us e the swas h pl at e t o mechanical ly rais e hydrauli c pres s ure; ins tead, a new hydraul icpump i s used to generat e hydrauli c pres sure and force the cl utch plat es toget her. The removal of t he s was h plat e all ows alarger overal l cl ut ch plat e s urface area, whi ch in t urn reduces t he hydrauli c pres sure requi rement. The press ure required toachi eve 1500Nm (1106 l b ft ) has been reduced from 100 Bar for Generat ion 3 coupli ngs to 40 Bar for Generati on 4coupl ings.
The posi ti oni ng of the Generat ion 4 coupl ing's i nput and output remains t he s ame as t he Generati on 3 coupl ing, asdescribed above.
By-pass Valve
On very low fricti on s urfaces, driveli ne drag t orque can occur, for exampl e:
revers e t orque from engi ne braking, orforced movement of t he dri ves haft by t he front wheel s .
This can i nfluence rear wheel s peed, maki ng it i mpos si ble t o determine the t rue fricti on capabil it y of the rear wheel s, bydis t orti ng t he wheel s peed s ignal. To prevent thi s, t he acti ve on-demand coupli ng is des i gned t o open i mmediat el y inres ponse to a s tabil it y cont rol event . This i s achi eved by a by-pass val ve ins tant ly reducing sys tem pres s ure t o nomi nal .
To balance the 4 bar bas e press ure (s ee below for detai ls ), t he Generati on 3 coupling us es a large Bel levill e s pri ng to forcet he cl utch plat es clear of each ot her t o prevent torque transmis si on t hrough the coupli ng. Even at 0°C, t orque t rans mis s ionis reduced from 300 Nm to Zero wi thi n 10 ms . The Generat ion 4 coupling however, does not require a Bel lvil le s pri ng t os eparate t he plat es as t he coupli ng does not have a si gni fi cant bas e pres s ure pus hi ng t he plates together.
Accumulator
The further t he cl utch pl at es have to move in order to contact each other, t he longer it t akes to di spl ace the hydrauli c fl uidneces s ary t o buil d pres s ure and t rans mit torque. To count er thi s, t he Generati on 3 coupling incorporates an accumulat or.This retains a nominal 4 bar pres sure wi thin the hydraul ic circui t. Al though thi s is not enough pres sure t o caus e s i gni fi cantt orque transmis s ion t hrough the coupli ng, i t forces t he plat es very clos e t oget her so that very l it tl e fluid di s pl acement i srequired t o achi eve full engagement and maxi mum t orque t rans fer. Ful l torque t rans miss i on can be achieved i n 150 ms .
On Generat ion 4 coupli ngs , t he 150ms act ivat ion t ime is achieved through the us e of a Bel lvil le s pri ng t hat acts to pus ht he plates t ogether (wi thout caus i ng si gnifi cant t orque t rans mis s ion t hrough t he coupl ing). As t he pump i s notcont inuousl y us ed to create t his bas e pres s ure (as i t was wit h Generat ion 3 coupli ng), improvement s i n fuel economy havebeen achi eved.
Wet Clutch Pack
The clutch pack is made up of 7 pairs of plat es ; t he inner dis cs are produced from hardened st eel wit h t he out er dis csmanufactured from s t eel wi th a s int ered face. The clutch pl ates operat e in trans mi s si on fl uid.
Torque t rans mis s ion acros s t he clutch pack is li mit ed t o 1500 Nm (1106 lb ft ). This ens ures t he l ower gears ret ai n anelement of front-wheel -drive for t ract ion s t abi lit y. W i thin the hi gher gears the coupl ing i s t heoreti call y capabl e oft ransmit ti ng all t he dri ve to the rear axle; al though condit ions woul d have to be ext reme for t his t o occur.
PRINCIPLES OF OPERATION
Generation 3 Couplings - up to 2009MY
An i nt ernal electroni cal ly-controll ed pump provides hydrauli c pre-charge pres sure wit hin the coupling. The pre-chargepres s ure s upplies t he requi red operat ing pres s ure to the clut ch plates to el imi nat e i nit ial wheel -s pin as the vehicleaccelerates from s tandst il l.
In conjunct ion wi th the pre-charge pres s ure a mechanical hydraul ic pump operates wi thi n the cl utch plat es to s upply thecoupl ing's mai n hydraulic operat ing pres sure. The mechanical pump is funct ioned by the 'i nput ' and 'output' of t he coupli ng:
input - dri ves haft connect ion from the front axle,output - different ial connecti on to the rear axl e.
Any s peed di fference bet ween t he front and rear axl es wil l st art t he operat ion of t he mechanical hydraul ic pump. Theamount of hydrauli c pres s ure appli ed to the cl ut ch pack by the pump det ermines the gap bet ween t he cl utch plat es. Forexampl e, the great er the hydraul ic pres s ure, t he s maller t he gap between t he plat es and s ubs equent ly t he great er thet orque transmit ted t hrough t he coupli ng from the front axle t o t he rear axle.
This mai n hydrauli c pres sure is des i gned t o t rans mit the t orque for tract ion demands of off-road drivi ng, and t o provi delock-up as requi red.
Generation 4 Couplings - from 2009MY
The Generati on 4 coupl ing s t il l us es an el ect ri cal ly-controlled pump to provide hydrauli c pre-charge to el imi nat e wheel-s pinfrom st ands t il l; however, the s ame pump is al s o used to provi de t he coupli ng's mai n hydraul ic operat ing press ure.
The pri nci pl es of transmit ti ng torque through t he clut ch pl ates remains t he s ame, as des cri bed above for the Generat ion 3coupl ing.
6. W ARNING: High t orque applicat ion.
• CAUTIONS:
The s peci al tool s hould be t urned count erclockwis e t o ins t al l the pi nion s haft nut.
Do not us e ai r tools to i nst all t he nut. Fail ure t ofol low thi s ins truct ion may res ult i n damage t o thecomponent .
• NOTE: 250 Nm (184 lb.ft) i s t he mi ni mum torquerequi rement to begi n collaps ing t he pini on s haft s pacer.
Us ing t he s peci al t ools i nst all t he new pini onnut.Tight en to 250 Nm (184 ib. ft).
6.
7. CAUTIONS:
Make s ure the specified t orque t o rot ate thepini on s haft is not exceeded. If exces s prel oad isapplied to the joint t he pinion s haft s hould be removedand a new col lapsi ble s pacer, pinion shaft tail beari ng,pini on s haft tai l bearing cup and pinion nut mus t bei ns t alled.
The s peci al tool s hould be rot ated at 60 rpm (1xrevolut ion per s econd) t o produce a cons i st ent reading.
The pi ni on s haft s houl d be rotat ed through t woful l revolut ions by hand before the t orque meas urementi s performed.
Us ing t he s peci al t ool, check t he t orque requiredt o rot ate the pi nion s haft . The specified t orquei s 1.1 Nm +/- 0.2 NmIf the s pecifi ed t orque t o rot ate the pi ni on s hafti s not reached, usi ng t he s pecial t ool s, t ight ent he pinion flange nut in one degree increment sand check t he rot ati onal t orque after each unt ilt he s pecified t orque of 1.1 Nm +/-0.2 Nm i sachi eved.
7.
8. CAUTION: Do not l ubricate the pi ni on oil s eal.
Us ing a s ui table pres s, t he s peci al t ool and adapt eri ns t all the pi nion beari ng oil s eal .
8.Inst all t he crown wheel ass embly.9.
Publi s hed: 11-May-2011
Front Drive Halfshafts -
General SpecificationItemSpecification
TypeFully fl oat ing, s ol id shafts wi th inner and out er cons tant velocit y joi nts
Recommended Lubricant
ItemSpecification
Front dri ve halfshaft (auto onl y)W ei con ant i-s ei ze greas eOut board joi ntUs e greas e s upplied wit h repl acement boot ki t
Inboard joi ntUs e greas e s upplied wit h repl acement boot ki t
Torque Specifications
DescriptionNmlb-ftExtens ion s haft beari ng anchorage t o bl ock bolt s - 3.2L Pet rol4835
Extens ion s haft beari ng anchorage t o t rans mis s ion bol ts - 3.2L Petrol2518
Extens ion s haft beari ng anchorage t o bl ock bolt s - 2.2L Di es el6548Extens ion s haft beari ng anchorage t o t rans mis s ion bol ts - 2.2L Dies el2518
Front halfshaft to hub bol t*45 + 80°33 + 80°
Heat s hi eld t o beari ng anchorage107* New nuts/bolts must be fitted