Yes, you are correct it is only a 3 speed. However, it is a very durable transmission. Depending on the gearing it should be OK for highway driving. I re-geared mine to 4.10s and now it tachs about 3000 at 60( It has been a few years but I want to say it was spinning around 2500 at 65 when stock.) A little high for my likes but most all of my driving is on local roads unless I am heading to the trail.
1990 Jeep YJ 4.2
Howell EFI, BDS 3.5" lift, M.O.R.E 5/8" Boomerang shackles, 1" Daystar BL, 1" JKS MML, TFI, Crager soft 8s w 35" Dunlop Mud Rovers, Ford 8.8, 4.88s, Dana 30 E-Locker, Terra Flex SYE, Tom Woods CV shaft, Warn M8000.