LSD or open diff?

[Bazcam]

I,ve had a rumbling vibrating sort of noise coming from the drivetrain on
my truck for a while now, only does it whilst cruising, not when accelerating
or slowing down.
I put the truck on axle stands and ran it. It sounded like a pinion bearing is
knackered, certainly diff related.

No worrys, I have a spare here donated by gary r, which I fitted today.
I've just been for a test drive, its terrible,it feels like I've got square wheels!

Something I noticed when it was jacked up, if i turn one wheel in any
direction the opposite wheel follows in the same direction, so its behaving
like an LSD, not like you would expect an open diff to behave ie opposing
wheel would turn in the opposite direction.

Have I just fitted an LSD and filled it with EP80/90, causing this problem?
Though if it was an LSD I think Gary would have mentioned it.

With the two diffs on the bench, would they look any different?

[wishbone]

Open diff you can see right through the driveshaft holes. LSD you can't.(Think the clutch mech blocks it)

[Bazcam]

Looks like I've fitted an LSD then.
I thought the replacement diff just had a different carrier when I
could'nt see right through.
Whats the likely outcome of filling with EP80/90 instead of LS oil?

[Bazcam]

Ok, wee bit embarrasing this one, looks like the "terrible diff" was'nt
the problem, I'd overgreased the sliding yoke on the propshaft, duh.
Amazing the effect this can have, the truck felt freakin terrible, square
wheels was no exaggeration.

The truck still has the original problem though.