Replacing a Discovery 3 front differential

How to replace the front differential on a TDV6 Discovery 3 and Range Rover Sport

This 2007 Discovery 3 TDV6 had recorded around 135,000 miles when the owner started to hear noises from around the front axle and the front differential. An inspection in the workshop found the front diff was indeed making a loud grating noise, even when the front wheels were rotated slowly by hand. The oil in the diff was discoloured and had a burnt smell about it. The inspection also revealed that the front diff’s breather pipe, which runs from the diff up through the engine bay and comes out between the side of the engine and the power steering fluid reservoir, was blocked. This has been a known problem on both Discovery 3 and Range Rover Sport, and may have resulted in the front diff overheating and eventually leading to bearing failure. 

The Discovery 3 front differential is a self-contained unit fixed to the vehicle underframe, rather than sitting inside an axle assembly, as in older beam axle Land Rover models. They have generally proved to be reliable, however the breather pipe was modified to prevent it becoming blocked, which could result in moisture building up inside the diff casing which, thus contaminating the oil and possibly causing overheating, leaks or bearing failure. That might have been the cause of the problem in this case.

No electronic equipment or special tools (other than a vehicle lift) are required. Needing to have the vehicle raised with both front wheels removed and with enough space to work underneath is not considered practical or safe with this vehicle type with normal DIY equipment. And, like many jobs on newer Land Rover models, although replacing the affected part is relatively easy, the difficulty is in removing other parts to reach the defective component. 

For these reasons, this feature, rather than explaining how to do the job, concentrates on showing what will need to be done by the garage so that, if your vehicle needs this work, you will have a good idea what they will be doing, and the costs involved. Here, we show how Madison 4x4, near Thirsk, tackled the job. Both axle halfshafts need to be removed. The pictures show the driver’s side halfshaft being removed first, before moving over to repeat the job on the left side.

Fitting the new differential 

Once the new diff is in place against the chassis, some manipulation is needed to align the mounting holes before fitting the bolts and tightening to the specified torque settings. We made sure the plastic breather pipe was securely connected to the short breather tube on the top of the diff, and that the pipe was free and running clear up through the engine bay. Otherwise, re-assembly is a straightforward reversal, using a new O-seal on the driveshaft support tube and sealant on its flange face, and with a few extra pointers in the pictures below.

Tools

Vehicle lift, general workshop tools including 13 mm, 22 mm, 23 mm, 24 mm spanners and sockets, long extension bar, large pry bar, E10 Torx bit.

Parts and costs

The final drive front differential is part number TAG500140. Prices range from around £690 upwards to over £1750. Many replacement differentials are sold as an exchange unit, with a surcharge if the old unit is not returned. The front diff requires 0.61-litre of alonglife fully synthetic 75w-90 oil, part number TYK500010 and costs around £20 per litre. This oil contains unique additives which Land Rover say “enhances the differential’s operation”, whilst the service specification says that no other oil should be used in the front diff.

Time: 4-5 hours Costs: £700

Contact

The work was carried out by Maddison 4x4, Water House Farm, Station Road, Topcliffe near Thirsk, YO7 3SG.

Web: www.maddison4x4.com

Health and safety

• When planning to work underneath a vehicle, ensure lifting and support equipment is correctly rated and in serviceable condition. • Ensure the vehicle is securely supported and cannot be dislodged. • Work should always be carried out to Land Rover specifications and procedures. This job is not suitable for DIY unless you have the required competence, knowledge and facilities.

Click on the gallery below for our handy step-by-step guide…

Most Popular

Driving test update to preserve the manual gearbox
Dacia Duster gear lever
News

Driving test update to preserve the manual gearbox

With more drivers learning in autos and electric cars, the DVSA is looking to update the driving test so people can still drive manuals in future
16 Jun 2021
Ineos Grenadier prototype 2022 review
Ineos Grenadier prototype
Ineos Grenadier 4x4

Ineos Grenadier prototype 2022 review

Can the Ineos Grenadier really fill the mud-splattered void left by the old Land Rover Defender? We take a first drive in a prototype to find out...
15 Jun 2021
Illegal car modification hotspots revealed
Volkswagen Polo exhaust
News

Illegal car modification hotspots revealed

Gloucestershire has the highest proportion of illegal car modifications, with altered number plates the most common breach
14 Jun 2021
New 2021 Vauxhall Astra to offer plug-in hybrid power
Vauxhall Astra render
Vauxhall Astra

New 2021 Vauxhall Astra to offer plug-in hybrid power

The new Vauxhall Astra will get a plug-in hybrid powertrain and a more premium image - here’s how it could look
17 Jun 2021
Tesla Model 3 police car all set for evaluation by UK emergency services
Tesla Model 3 police car - front
News

Tesla Model 3 police car all set for evaluation by UK emergency services

Tesla hopes to offer UK police forces a new zero-emission emergency responder option with the Model 3 police car
17 Jun 2021
New Renault Arkana 2021 review
Renault Arkana - front
Renault Arkana

New Renault Arkana 2021 review

Does an eye-catching coupe-SUV body give the new Renault Arkana the edge over other mid-size SUVs? We find out...
16 Jun 2021
New Vauxhall Astra prototype review
Vauxhall Astra prototype - front
Vauxhall Astra

New Vauxhall Astra prototype review

A new Vauxhall Astra is on the way and we've driven a prototype ahead of its official arrival
14 Jun 2021
New Porsche 911 GT3 Touring tones down the styling
Porsche 911 GT3 Touring - front
Porsche 911

New Porsche 911 GT3 Touring tones down the styling

The optional Touring package aims to bring a few creature comforts to the track-focused Porsche 911 GT3
15 Jun 2021
UN report highlights ethical problems with electric cars
Electric car charging
News

UN report highlights ethical problems with electric cars

Analysis reveals lithium refining takes 65 per cent of Chilean region’s water, while 40,000 child miners dig for cobalt in DRC
14 Jun 2021
New Nissan Qashqai 2021 review
Nissan Qashqai 2021
Nissan Qashqai

New Nissan Qashqai 2021 review

We get behind the wheel of the larger, more comfortable and higher-tech Nissan Qashqai SUV in the UK
16 Jun 2021
'I was cynical about Hyundai's aim to be the world's 2nd biggest carmaker, not now'
Opinion Genesis Hyundai Ioniq
Opinion

'I was cynical about Hyundai's aim to be the world's 2nd biggest carmaker, not now'

Steve Fowler is impressed by Hyundai's electric cars, its N division and now its luxury Genesis brand
16 Jun 2021
New SsangYong Korando e-Motion breaks cover with electric power
SsangYong Korando EV
Electric cars

New SsangYong Korando e-Motion breaks cover with electric power

The new SsangYong Korando compact electric SUV will be on sale later in 2021, says the financially stricken South Korean manufacturer
15 Jun 2021
Dacia unveils new badge design
Dacia badge
Dacia

Dacia unveils new badge design

The new Dacia branding will feature on the company’s cars from 2022, with the Bigster being the first candidate
17 Jun 2021
‘Our switch to electric will soon make driving manual cars a lost art'
Gearknob
Opinion

‘Our switch to electric will soon make driving manual cars a lost art'

Want to drive a manual car? You need to take your test in a manual car. So what happens once all driving-school cars are automatic EVs?
8 Jun 2021