Front differential identification

[87 hardbody 4x4]

I need to replace my side shaft seals. How do you tell which model? 180 or 200?

[Desert Rat]

If it's a 4 cylinder, you have an R180. If it's a V6, you have an R200.

The outer flanges should be the same on both and halfshafts should interchange - the bolt pattern has changed over the years, so as long as you get one for the right year, I think you'd be OK.