Thread: Diff ratios

Yes, they should be both 4.7:1 ratio, counting the revolutions of the wheel in regard to the propshaft should confirm.

As Mark says - all Series Landrovers (except some very early 8)" and Stage 1 V8 or Isuzu) came from the factory with 4.7:1 interchangeable diffs. Since the RR classic/Disco diffs at 3.54:1 are interchangeable, it is worth checking that someone has not done a swap in the past. (These are the most common replacements, there are others.)

john

Originally Posted by JDNSW

As Mark says - all Series Landrovers (except some very early 8)" and Stage 1 V8 or Isuzu) came from the factory with 4.7:1 interchangeable diffs. Since the RR classic/Disco diffs at 3.54:1 are interchangeable, it is worth checking that someone has not done a swap in the past. (These are the most common replacements, there are others.)

john

Just a question on this:

Will the Series coarse spline diff centers fit the RRC/early Disco 1 side shafts?

Can I drop an early RRC axle into my S2A and just swop centers to keep the 4.7 ratio?

Originally Posted by jakeslouw

Just a question on this:

Will the Series coarse spline diff centers fit the RRC/early Disco 1 side shafts?

Can I drop an early RRC axle into my S2A and just swop centers to keep the 4.7 ratio?

Yes.
I have done the opposite, pulled the diff centre from a Disco1 and put it in my 80" fitted with series 2 fully floating axles to up the ratio from 4.7 to 3.5.
Both 10 spline

Originally Posted by jakeslouw

Just a question on this:

Will the Series coarse spline diff centers fit the RRC/early Disco 1 side shafts?

Can I drop an early RRC axle into my S2A and just swop centers to keep the 4.7 ratio?

As far as the drive mechanicals go, yes. But the track is different and the RRC has coils not leaf springs, and the track rod and the leaf springs need to occupy the same space - which has led to a number of creative solutions, none of which seem to be particularly satisfactory!

John

Originally Posted by JDNSW

As far as the drive mechanicals go, yes. But the track is different and the RRC has coils not leaf springs, and the track rod and the leaf springs need to occupy the same space - which has led to a number of creative solutions, none of which seem to be particularly satisfactory!

John

Drat. One solution is SOA?

I don't mind welding in leaf spring perches, but track rod mounting mods could be an issue.

Originally Posted by jakeslouw

Drat. One solution is SOA?

I don't mind welding in leaf spring perches, but track rod mounting mods could be an issue.

There are four basic approaches.

1. modified track rod with bends (or offsets) in it to clear springs and diff - unlikely any engineer would ever approve it.

2. Build very high spring pads - probably most used, reduced ground clearance, needs either non-standard springs or changed spring mounts and shackles.

3. Use a LHD swivel housing on the right, move the track rod to the front, and attach the drag link to the track rod. The most satisfactory, but LHD components are a bit thin on the ground, and making the track rod to satisfy an engineer likely to be expensive.

4. Rotate the axle housing so the track rod is higher. Increased castor, problems with prop shaft U-joint angles. Sometimes combined with (2).

John