1987 Defender Rear Differential

[Jaroslav]

Hi all,

The rear diff on my 1987 Defender is busted.

Somebody offered me a pair of Disco 1 axles, which, I've been told, have a slightly higher gear ratio, but I am not sure if they would be suitable for a diesel-powered unit. On the plus side, I'd get all 4 wheel disc brakes and probably better mileage.

Could somebody please comment on the wisdom of such an upgrade? Would it even fit? I've tried to google the topic and found somebody saying that the propellor shaft is shorter on the Discovery? Is it true?

Thanks,

/Jaroslav

[western]

if your Defender is a 90 the Discovery axkes are a good swap, ratio is the same on all permanent 4x4 land rovers since the first range rovers came out.

[paul stage1v8]

Technically it is not a defender, just a 90/110. If it is a 90 the diff from the disco is a straight swap, on a 110 it has a salisbury which has a shorter driveshaft than you would need with the disco diff, the disco diff is possibly also not strong enough for a 110, although they are all the same ratios.

[Jaroslav]

Yes, it's a Salisbury. So, you're saying Dicso diffs won't fit. Thanks, saved me a lot of trouble (and money).

By the way, the guy who sold me this truck (an ex-British military, LHD, diesel) claimed that the rear differential is heavy duty. But my workshop manual seems to be implying that if the serial number number starts from 21S (mine is 21S28345B), then it's standard. How standard would be different from heavy-duty? Is the difference only by the number of pinions inside (4 instead of 2)?

Thanks,

Jaroslav

[paul stage1v8]

The salisbury is a heavier duty diff than the rover diff which is probably what he meant. There is a heavy duty salisbury also, which I believe has heavier axle tubes but internally is the same, very rare though, as far as I know only used on the armoured 110.

[western]

Forget using a Discovery rear axle on a 110, it's just not built to cope with the 110's maximum fully loaded weight. have a look in the tech archive index, diesel_jim did a write up on how to convert a drum braked Salisbury 110 axle to disc brakes.

[Guest diesel_jim]

The salisbury is a heavier duty diff than the rover diff which is probably what he meant. There is a heavy duty salisbury also, which I believe has heavier axle tubes but internally is the same, very rare though, as far as I know only used on the armoured 110.

^^^^ What he said... the internals are the same, it's just the casing is slightly beefier.

although even in standard form, the axle tubes are a good 12mm or so thick! i cut the shock mounts off of one a while back with the oxy torch, and was suprised how thick it was.

unless i had an uber-rare HD version, and then proceeded to cut it up with the gas axe..... D'OH!!!!!!!!!!!!!!!!!!!!!! (i never checked the serial number)

[Jaroslav]

Here is an excerpt from this page: http://www.rimmerbros.co.uk/rimmer/land-ro...tial%20-%20Rear

There are 2 types of rear axle fitted to the Land Rover:

1. The conventional Rover axle, from which the differential is removed as a complete unit on the front of the axle.

2. The Salisbury axle, which has an access plate on the rear of the axle for differential removal.

Rover axles have 2 types of differential, as follows:

2 pinion (standard duty) or 4 pinion (heavy duty), referring to the number of pinion gears in the differential itself.

Vehicles fitted with 2 pinion diff's have 10 spline halfshafts up to VIN KA930455 (1993), & 24 spline halfshafts from VIN LA930456 (1994) on.

Vehicles with 4 pinion diff's are all fitted with 24 spline halfshafts.