ACCO 1850d two speed diff question

I bought an 1990 Acco 1850d with an Eaton two speed diff. THe two speed mechanism (electrical side) does not work ATM so I am trying to work out what gear it is in. ie low speed or high speed.

It does 1800rpm at 80km/h with the Allison 4 speed in 4th gear. Any one with any idea.

Turbotrana - I'd have to say that the 2-speed is in high range with those indicated RPM's and speed. If it was in low range, you'd be stuck at a little over 60 kmh at maximum revs.

Cheers - Ron.

thanks