Diff numbers?

[trolleybus]

I have two spare diffs and am curious as to their origins.
Been searching this morning but can't find and info.
One has MEC16120 on it and the other MG61256.
I think the MG one is a late TC/S but can't find any reference to a MEC number.
Any one know I would be grateful.
Bernard.

[johnnydog]

The MG diff is as you suspected a 2.5 PI / 2500 (manual and auto). It should have a dab of red paint on the output flange nuts.
From the info I have at hand, the MEC diff is off a 2000 saloon with auto transmission.

Just for info purposes, the other identifiers which are stamped on the bottom flange of the casing are -
ME - 2000 saloon manual
MEA - 2000 estate manual
MG for 2.5 / 2500 manual / auto
MGA 2.5 / 2500 estate man / auto
MEC - 2000 saloon auto
MED - 2000 estate auto

My notes also state that 3.7 diffs have a dab of yellow paint of the output flange nuts, whereas 4.11 have white. How true this info is I'm not sure. The red paint on MG diffs however is definitely correct.

It is also worth bearing in mind that due to the age of our diffs, unless you know the history of a car, there is a small possibility that the innards / casing may have been swapped about during any repair work, so the only accurate way to check which diff you have is to count the the number of turns of the input shaft relative to the turns of the output shafts. The back plate can be swapped for a saloon or estate as necessary.

[trolleybus]

Thanks Johnny,
That all tallies with my two diffs.
Doing the turning the input shaft thing I get 3.25 turns for the yellow and 3.5 turns for the red using the four bolt holes as mafkers.
Cheers B.

[johnnydog]

I think you are a slightly out with your counting on the 3.7 (yellow), but virtually spot on with the 3.45 (red)!