Overdrive Bundle Kit (Defender)

(7 customer reviews)

£1,925.00 £1,885.00 Excl. VAT

Overdrive bundle kit for the Defender.

Kit includes:

Defender DS Roamerdrive Overdrive

LT230 High Capacity Sump (*sump not compatible with V8)

LT230 Temperature Oil Gauge


CUSTOMER NOTICE: Due to delays with our supply chain on Roamerdrive units processing for dispatch may take slightly longer in some cases.  We expect all orders to be dispatched within 7-10 days (but we will always aim for earlier where possible).

Thank you for your patience at this time.


SKU: RoamerBundleDS Categories: ,


Overdrive Bundle Kit (Defender)

Roamerdrive bundle kit for the Defender.

Kit includes:

Defender DS Roamerdrive Overdrive

LT230 High Capacity Sump (*sump not compatible with V8)

LT230 Temperature Oil Gauge

Defender DS Roamerdrive

The Model DS ROAMERDRIVE is an upgraded version of our model DX first introduced in 2006. The upgrades on the DS model include a more open front-end architecture that enables oil shared with the transfer case to be circulated more efficiently. An Archimedes screw on the main shaft retains oil behind a ‘dam’ in the front cover to ensure efficient lubrication at high speeds and on steep inclines. A crush washer on the nose of the overdrive provides bearing preload on all variations of transfer case.

Other than the use of epicyclical gear technology, the DS has little in common with other designs of overdrive sold for five speed Land Rovers in the past. The overdrive has no electrical components or cone friction clutches and no dedicated oil sump. It is a very compact unit that shares oil with the transfer case and does not interfere with exhaust pipes or other fittings on the Land Rover.


The DS overdrive can be fitted to any five-speed 90, 110 or 130 model Defender Land Rover from the time of introduction in 1985 up to and including the TD5 model.   Apart from the specific exceptions listed below, the DS-B overdrive will fit all models of 90, 110, and 130 DEFENDER type Land Rover with the following motors:



2.5 Diesel

2.5 Diesel Military

2.5 Turbo

200 Tdi

300 Tdi


The DS model can also be fitted to vehicles with popular replacement engines such as the International 2.8 and TD5 engines that have been modified to produce more power.  Some restrictions apply to such modified vehicles   see installation instructions ».

The overdrive takes about three hours to install and is supplied as a complete kit that includes everything required to make the installation apart from lubricating oil.

The overdrive is engaged using a simple hand lever.  The lever is conveniently located on the centre console immediately adjacent to the Hi/Low range knob.

The DS-B will not fit in the following cases:

  1. Models fitted with four speed gearboxes.
  2. Models fitted with 230 transfer case suffix A and B found on early 90 and 110 models. You would need to fit the later suffix transfer case used up to the TD5 model.
  3. Models that have been retrofitted with Discovery transfer cases.
  4. Models that have been retrofitted with six speed gearboxes. You would need to fit the suffix transfer case used up to the TD5 model.

See DS Installation Instructions for more information ».


To engage the overdrive when on the highway, wait unit you are travelling at about 50 mph (80 kph) in fifth gear. Depress the clutch and move the actuating lever forward exactly as you would when changing gear.  When the clutch is released the engine RPM will drop by 28% and the noise level in the cab of the Land Rover will drop significantly. As changing traffic and gradient dictate, you can engage and disengage the unit.

In urban driving you can engage and disengage in third and fourth gear to get the best working ratios.  You will find for example that it is much easier to engage the ROAMERDRIVE in fourth gear than to shift the main gear lever into fifth.

In off road conditions when driving in low range the overdrive is useful for raising the ratios making it unnecessary to engage and disengage the high range lever.

Driving a Land Rover with a Global Roamer overdrive is a pleasant experience as it is possible to have a normal conversation at relatively high motoring speeds

The inclination to drive faster with the overdrive negates considerable fuel savings to be had if one retains one’s original driving patterns. Our experience shows that drivers who use the ROAMERDRIVE at moderate speeds will save up to 15% on their fuel costs. The long-term saving of less wear and tear on engine and drive line components are also considerable. Bear this in mind and your overdrive will pay for itself quickly.

LT230 High Capacity Sump

Transfer case sump oil coolers are designed to replace the sump covers supplied as standard equipment. These covers are stronger than the originals and have cooling fins to keep the oil in your transfer case cool in harsh conditions.

The existing bolts are used for installation. The sump cover is significantly stronger than the original and adds about 1/2 litre to oil capacity. Existing ground clearance is not compromised.


  • Defender, Discovery and Range Rover Diesel LT230 transfer box applications

*it does not fit V8 or TDCI models

LT230 Oil Temperature Gauge

This oil temperature gauge is a high precision mechanical temperature gauge with a full 270 degree sweep. The unit is designed to compliment transfer case sump cover and fits directly to a pre-drilled port in the sump cover. The unit fits into a standard two inch mounting hole and operates completely independently of electrical power. A 12 volt lamp supplies illumination. The gauges are far more accurate than common electrical types using thermistor senders. These gauges can also be used to measure cooling water temperature or engine oil temperature in commercial or marine applications. The sending tube is 1,800mm long, and contains pressurised fluid so it cannot be shortened – but you can coil surplus tube behind your dash.


Below are the Warranty terms direct from the manufacturer (  No warranty is given by Syncro Gearboxes:

“Unless otherwise stated elsewhere, ROAMERDRIVE overdrives are warranted against defects in materials and workmanship for a period of one (1) year from date of purchase.

This warranty is made to the original purchaser only and covers ROAMERDRIVE overdrives that have been installed on the same vehicle since purchase. We (or our appointed distributor) will repair or replace any overdrive unit that suffers from manufacturing defects within the warranty period.

In order to take advantage of this warranty the unit must be returned, at your expense, to the distributor. If you purchase the overdrive directly from our factory in West Vancouver, the unit must be returned to our factory at your expense.

PRIOR TO RETURNING a unit under warranty, you must first contact your distributor, or our factory in West Vancouver, to discuss your issue. Once we have all the necessary information, we will issue a Warranty Return Approval document. We will NOT accept any unit that is returned under warranty if it has not first been issued a Warranty Return Approval document.

Your Warranty Return Approval document will have detailed instructions on the shipping documentation that must be sent with the overdrive unit being returned under warranty. Not following the warranty return shipping instructions may result in unnecessary additional government charges being levied, which will be your responsibility.

Once warranty work is done, our distributor or the factory will return the unit to you freight prepaid.

Transfer case gear noise is not covered under this warranty.   If your transfer case gears are worn, then your noise problem can be rectified by replacing these gears, not by replacing the overdrive.  It should be noted that initial cases of minor gear noise tend to be self-correcting as the new and old gears in the gear train bed in together over the first 10,000 km.

Under no circumstances will we cover the cost of removing or replacing the overdrive on a vehicle, or be responsible for any other expenses whatsoever.

Our warranty does not cover damage caused by lack of lubrication, use of improper oil, or damage caused by overheating the ROAMERDRIVE in applications with non-standard engines and gear boxes.”

Additional information

Weight 23.01 kg

7 reviews for Overdrive Bundle Kit (Defender)

  1. Ian (verified owner)

    Overall a grate pice of kit only shame is it doesn’t come with a new bearing so you have to supply your own or take you old one of the shafts you remove otherwise very happy. It still wines at the moment but have been reassured that it should be quieten down when the gears bed in.

  2. Ron Fowler (verified owner)

    Couldn’t have better advice or customer service!

  3. Robert Fisher (verified owner)

    This is the second overdrive I have installed now and again I think it’s the best.
    Makes you Defender driving experience 100% better you will cruise at 70 and use less fuel.
    I would recommend to everyone.

    Thank you synchro Gearboxs for a great product

  4. Robert Fisher (verified owner)

    O M G What a difference this makes to my defender.
    Well worth fitting, if you have a reasonable idea of mechanics it should not be a problem.
    Every thing you need is supplied and it is nearly all done from inside the cab.
    Fantastic bit of kit

  5. Andreas M. (verified owner)

  6. Emanuel S. (verified owner)

    Extremely efficient and competent people who help on request. Totally satisfied to have dealt with you all at Syncro Gearboxes 😀

  7. Phillip Knechtel (verified owner)

    Great piece of kit! All of the reviews that I have read agree that this is a worthwhile addition. Now my 110 is good for hills, off-road, and motorway. I added a rev counter from Croytec at the same time so I can monitor the revs. At 70mph I’ll be doing around 2000 rpm which is a great result. Following some initial queries regarding the temperature gauge the team made enquiries and all is now sorted.

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