Outer Limits 4x4 Board

Does anybody know what the differences are, If any. between a Range rover classic LT230 transfer box and a Land rover 90 XD LT230 transfer box?
As i am trying to find a transfer box to replace the viscous diff in my range rover classic.

High range ratio is main dif.

http://www.ashcroft-transmissions.co.uk ... ory_4.html

http://www.ashcroft-transmissions.co.uk ... ry_11.html

regards
Michael.

The serial number is 22D5941116 does anybody know what this equates to?

Sorry thats wrong, look at this

Rover Transfer gear box
introduction
Transfer Box
The 4-sp gearbox, fitted to all manual Range Rovers from 1970 to 1983, has a transfer box which is integral with the gearbox assembly and is, therefore, inseparable from it. The 5-sp manual gearbox, introduced in July 1983, has a separate transfer box as follows:
1983 to approx. 1984 models are fitted with Land Rover's LT230R unit, which is gear-driven and incorporates a manually selectable diff-lock.
1984 (approx.) to Oct 1988 models are fitted with Land Rover's LT230T unit, similar to the LT230R but with taper bearings on the intermediate shaft instead of the previously used needle roller bearings.
Oct 1988 onwards models are fitted with a Borg Warner chain-driven transfer box, incorporating a viscous differential lock.
Automatic models also have separate transfer boxes, as follows:
3-sp autos are fitted with either the LT230R or LT230T transfer boxes.
4-sp autos to Sept 1988 are fitted with the LT230T transfer box.
4-sp auto vehicles from Oct 1988 onwards are fitted with the Borg Warner chain-driven transfer box.
This section includes fully reconditioned transfer gearboxes, as well as the components associated with the transfer box, such as the speedo cable. Also included is the parking brake, since this operates on the rear of the transfer box rather than the rear wheels, as is conventional. As with the main gearbox, we have only listed a limited selection of internal components, because repair is rarely as cost-effective as replacement with a recon unit.
Unit Identification
Identification of the transfer box fitted to your Range Rover is fairly straightforward:
4-sp. All 4-sp manual vehicles have an integral transfer box.
5-sp/LT230R. LT230R transfer boxes fitted to 5-sp vehicles have a serial number (located on the rear lower face of the transfer box) which begins 15D.
5-sp/LT230T. LT230T transfer boxes fitted to 5-sp vehicles have a serial number beginning 27D or 28D.
5-sp/Borg Warner. Vehicles fitted with the BW transfer box are easily identified from the transfer gear lever inside the car, which has a simple fore & aft plane instead of the H-gate of earlier vehicles.
3-sp Auto/LT230R. LT230 transfer boxes fitted to 3-sp auto vehicles have a serial no. beginning 14D.
3-sp Auto/LT230T. LT230T transfer boxes fitted to 3-sp autos have a serial no. beginning 26D.
4-sp Auto/LT230T. 4-sp auto vehicles with the LT230R transfer box have a serial no. beginning 28D
4-sp Auto/Borg Warner. These vehicles are easily identified by the transfer gear lever inside the car, which has a simple fore & aft plane instead of the H-gate of earlier vehicles.
Gear Ratios
The high-gear ratios of the transfer boxes are as follows:
LT230R
14D (Auto) 1.003:1
15D (Manual) 1.192:1
LT230T
26D (Auto) 1.003:1
27D (Manual)1.192:1
28D (Man & auto)1.222:1
Borg Warner (Man & auto) 1.206:1

AFAIK, different model LT230's are interchangable, though some require a little work. No change in mounting to gearbox.

Rear output is same except for no speedo drive in later disco versions (with electonic speedo).

Front drive flange is different for series II disco, but can be replaced with the older flange.

Early rangie hand brake bolted to the t/case, but later LT230 don't have the tapped holes - the bosses are there and they can be drilled and tapped for the bolts.

There are different high range ratios.

Different methods of operating the h/brake - early models have links, later cable.

Those with taper roller bearings on the intermediate shaft are better than those with needle rollers. The taper roller version can be identified by the nut on the rear of the intermediate shaft (for adjusting bearing pre-load).

There was a problem with wear of the splines inside the input gear. The fix was a new gear with longer splines and a cross drilled hole to allow the oil to lubricate the splines. The new gear can be fitted to earlier LT230.

The ratio of a defender extreme transfer case is 1.411, as opposed to the 1.211 of Series 2 Discoveries. Obviously this makes the TD5 defender T. case the option of choice if you run/intend to run larger tyres. They are actually a bit hard to come by, so if you have one lined up, but don't want it, I'm sure other people on this forum might be interested to know where it is.

rustyveedub wrote:The serial number is 22D594111G does anybody know what this equates to?

The prefix 20D, 22D and 32D tells you that it is an LT230T from a Defender.

The number 594111 is used to create a unique serial number.

IIRC the suffix G corresponds with the year (or years) - but I may be wrong.