ive a 1983 2.25petrol ,88, i think there may be a half shaft /diff bearing worn . in the rear, got vibration at approx 30mph . replaced prop , still same . ive a good front one , are they the same? mine has 24 spline halfshafts ,is the diff end of half shaft same for the pre 80/81 rover diffs?...... on subject of diffs is there any point on a 3.54 diff in a series landy with stock engine?

Providing it is a gen series diff then yes they are the same at the diff end but if its a RR, Def or a Disco diff then no as they will fit the axle but at the diff end its 24 spline and you can't get a 24 spline 1/2 shaft for a series believe me I've tried, but for a stock 2.25P yes if 2.25D then no, hope this helps

Erm,

First off. Your vibration could be the pinion bearing in the diff. Check that by seeing if there is any up and down side to side movement.

Anything felt is too much. (Pretty much)

Diffs,

Front to back are the same,

Late 24 spline series III shafts have 24 at the drive flange end and are Std 10 spline diffs.

Early Rangy and discovery diffs are also 10 spline which are interchangeable however the ratio is taller ie 3.54:1 vs the series 4.7:1.

Make sure you have the same ratio front
To back because if you engage 4wd it will go bang if mismatched.

You can get aftermarket 24 spline diff end series shafts Ashcroft make them as a us replacement option however quite rare.
LR never made a series Rover axle with 24-24.

thanks ! yes ill just stick with the normal diffs ,keep it simple and original eh