thanks mate. any idea on identifying the heavy duty diffs?
They are rover (now that I know)
some military spec 90's had HD rear diffs.
Now, assuming your 90 is all "standard" as it came from the factory and hasn't been molested, you can follow the following guides, although it may not be 110% accurate (if anyone has been fiddling with it)
so, standard drum braked 90 rear axle will be 2 pin diff, 10 spline halfshafts.
(assuming your 90 is drum braked rear), pull a halfshaft out, if it's 10 spline, then you've got a standard 2 pin diff. if it's 24 spline, then
you could have a HD 4 pin diff.
Pull the other shaft out, and look down through the hole, if, where the diff is, it's clear, then that's a 4 pin. if you can see a shaft going across the "hole", then that's 2 pin.
If you pull the diff out, on a 4 pin you won't be able to see any of the internal gears (it will look like an ARB locking diff, do a google search and you'll see what they look like), but if you can see the planet & sun gears then it's 2 pin.
Now, if your 90 was a later model, or someone has changed the rear axle to disc brakes, then you might have 10 or 24 spline shafts, but possibly (the more common) 24 spline
2 pinion diff, as fitted to rangies and disco's, these arn't HD, just have more splines. the only way to tell then, is to pull the diff out and look (if you can see the internal gears, as above)
