That 4.875 gear ratio tells me you have the 9" rear diff with the small front diff. At least here in the states, that was the ratio installed on the '92-'93 SR's that only had the 3.0 V6. Should be the RD25 if you have disc brakes or the RD46 if you have drums. No available traction aids for the small front diff. If you had the larger rear diff, the ratio would hav been either 4.636 or 4.900.

Boertijie, you should be running the RD46 rear diff and the front should be the RD110. Mitsu used the same diffs in the Gen I LWB diesels as they used in the V6 models.