Diff Building Tips

Differential Building Tips 

1.) Pinion Bearing

We would highly recommend to always change the pinion head bearing Land Rover part No: 539706, as it is very difficult to pull off the old pinion.  This bearing is the same on all Land Rovers apart from S1 1949 to 1958

Pinion head bearing  Land Rover Part No: 539706

Pinion tail bearing     Land Rover Part No:  539707


2.) Carrier bearings.

Metric Type Carrier.  1987>  Bearing Dia will be 73.5 mm,  RTC 3095

Imperial Type Carrier 1987< Bearing Dia will be 76.10 mm  RTC2726

Imperial Type Carrier  1976 <  These older diffs used         . 41045

Imperial Type to Metric conversion.

You can convert your old Imperial diff casing to metric by fitting a adapter ring over the metric bearing.

Bearings Adapters £12.50 each.  You will require 2 off per carrier.


3.) Fitment of the new pinion head bearing

Fitment of the new pinion head bearing can be simply pressed on.  A 6 inch length of scaffold tubing is just the right size to press / drift the bearing on with.

Land Rover Part No: 539706


4.)  Checking crown wheel and pinion height correctly

Machine blue is the best way of checking that you have set the crown wheel and pinion height correctly.  With the machine blue applied to several of the mating teeth with a tooth brush, turn the crown wheel around and inspect that the machine blue has been wiped centrally to the mating tooth. (See image on fitting instructions)

Machine blue can be purchased From KAM for £4 per pot.


5.) Crown wheel bolts

If you are pushing your axle to the extreme we would recommend replacing the crown wheel bolts as they can suffer from fatigue. 10 required per diff.  Part Number:


6.) 4 main carrier cap bolts replacement

The 4 main carrier cap bolts that hold the two bearing caps in place also suffer from large side loads and can bend.  Inspect that they are not bent and replace.  We recommend to replace these with 12/9 cap head bolts. KAM Part Number:


7.) Diff pegging.

This helps support the crown wheel from flexing on the bearing caps via a thrust pad that runs on the outside back edge of the crown wheel. KAM are developing an improved version.


8.) Diff back lash

This should be set at 4 to 8 thou using a dial gauge.


9.) Pinion Flange

All our pinions are splined to take a 24 spline pinion flange.  Inspect closely the ground area were the oils seal runs.  If this has a groove worn in then it should be replaced. Part Number:


10.) 2 Pinion Carriers

Inspect closely the cross shaft and make sure that the holes are not worn.  Any more than 0.2mm movement sideways will require the carrier to be replaced. KAM hold some stock of good secondhand 2 pinion carriers.  Best option is to replace with 4 pinion carrier.


11.) Run out problems with the carrier

Clean the 10 off crown wheel bolts and holes if you are refitting an old gear set or old carrier bolts.  If not cleaned then old stud lock can build up under the crown wheel face as you are tightening up the bolts and cases the crown wheel to clamp on to the partials that fall out.  This will causes the crown to have a tight spot and not run true.


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