vehicles NXC2**H and the early vehicles for sale to customers had the legendary Salisbury Powr-Lok lockable limited slip center differential in the LT95 4 speed gearbox.

In addition to the limited slip function in center differential, the center differential could also be locked

via a vacuum actuator knob close to the gear shift lever, exactly as we know about with all later

manual 4 speed Range Rovers during the 1970s.

The LT95 4 speed gearbox with integrated transfer box for high and low range selection was 

developed to suit two Land Rover projects - the Range Rover and the military Land-Rover 

Forward Control FC101. To achieve best possible strength to withstand the power from the V8

engine the transfer box was designed with permanent four-wheel drive via a third centre differential.

This center differential had both limited slip function with friction discs to secure best possible 

traction during regular driving. In addition the center differential could be locked to secure that both

axles had drive under extreme slippery conditions or if one wheel had no traction at all.

Salisbury Transmissions in UK developed and supplied the center differentials to the new LT95

gearbox. Salisbury had for many years been a trusted supplier of axles and axle differentials to

Land Rover. The Salisbury differentials are easily identified by its red color, either used in the

axles or in the LT95 gearbox.

All Range Rover with Suffix A LT95 gearbox was originally produced with red Salisbury center differentials. Important here is to be aware that the Range Rover #VIN Suffix A serial numbers 

center differential.

The red Salisbury center differential that was installed in all Suffix A LT95 gearboxes are identical

either with the Powr-Lok limited slip function of the very early Range Rovers or the later Suffix A            The limited slip friction discs in the Range Rover LT95 gearbox 

LT95 gearboxes without the limited slip function. Only the setup with limited slip friction discs in

limited slip version differ from the later one without the limited slip function. 

The vacuum actuated lockable center differential lock function are identical.

In the 'Range Rover - Technical Details' publication 789 from June 1970 is written;

The discontinuation of the limited slip function in the center differential was a last-minute decision 

because already in July 1970 a new 'Range Rover - Technical Details' publication 789A was issued

with this interesting changes:

In the official workshop manual 'Range Rover - Repair Operational Manual' - Issue 1 from 1970, in

section 37.01 is written:

In Issue 2 from October 1970 the 'limited slip differential' was replaced by 'lockable differential'.

The first Range Rover's with limited slip gearbox had different Recommended Lubricants than the 

later vehicles.

In the 'Range Rover - Repair Operational Manual' - Issue 1 1970 the following oils where required:

The idea with the limited slip function in the center differential was to achieve best possible traction

with a permanent 4x4 drive system. On the market in mid-60s there were not many modern leisure

four-wheel drive vehicles, called SUV today. Most common were the US Ford Bronco, Chevrolet

Blazer, Jeep Wagoneer and Toyota Land Cruiser, in addition to the Land Rover Series II. All of those

rather rugged driveline system compared to the refined and sophisticated driveline for the projected

Range Rover. 

Only really sophisticated four-wheel drive system on the market was the Ferguson Formula - FF -

which was low scale production, more seen on Formula 1-testing and Jensen FF in the 60s.

The Ferguson Formula system is explained in detail here.

Since there was not many comparable permanent four-wheel-drive system on the market with center 

differential, the development engineers at Land-Rover worked with the permanent 4x4 driveline to

both have the limited slip function as well as the lockable function to totally lock the center differential, the latter to have direct drive front and rear like the Land-Rover system and the US systems.

Back in the later part of the 60s the new Range Rover was seen as a more luxury vehicle for the 

farmer, engineering companies etc for with need for off-road driving or driving on rough roads.

What went out to be instantly after the launch of Range Rover in 1970 was that the new vehicle

was used more than 99% on paved roads, often by people the never before had drove a 4x4.                   Later in 1970 the friction discs was replaced by distance discs.

Maybe the need for better wheel traction was only needed on a slippery car-park at a sport event             No longer with the limited slip function, reason described to left.

or gymkhana.

In the time of launch, just before and right after, at lot of the automotive magazines made test drives

of the new Range Rover. The reaction to the new Range Rover was very positive, but the gearbox 

sometimes got comments about gear whine noise and rather rugged agricultural feeling.

Another comment was problems often found around the steering. In 1970 Range Rover had only a 

Also when driving at speed on slippery ground the car likely tended to get fish-tail feeling.

The limited slip in the center differential made the driveline system too 'stiff', so when the Range

Rover were driven on delicate surfaces or in special conditions like described here the vehicle 

became too uncomfortable.

The engineers at Rover found out that the limited slip in the center differential made problems. The 

recipe to eliminate these unwanted driveline behaviors was to withdraw the friction discs and only

have the space rings instead. Then the jerkiness and fish-tail feeling disappeared. 

Normally the very slippery conditions, like a muddy park yard or icy road, the length and speed 

to get back to normal conditions were so short and solved by the lockable differential function.

So it was decided that limited slip in the center differential gave more discomfort than extra benefit.