Nissan Patrol 4x4 (Africa)

hahaha..... naaa, I like the auto hubs. I only lock them if I am on a trail or know I'm going to be constantly on difficult terrain like Mozambique sand. Other than that its convenient to just be able to slip it into 4x4H from a tar road onto a sand road.

Ric, you can do that anyways with locked hubs. The TC is going to disengage the front end while in 2H. At least with manual hubs engaged, you know the front drive train is at speed (or darn close) when you go to 4H. I have popped the Sani into 4H at close on 130km/h a few times, and it does it with no problems. Even coming off gravel and back to 2H at just about any speed.

The advantage of having auto locks hubs is to reduce wear and tear and to use less fuel and have more power ....not much but everything helps
When the hubs is locked and you start driving its extra drag getting the front diff side shaft and propshaft turning .....

You are absolutely right there, in the Patrol under "auto" slipping into 4H at speed is definitively not the ideal.

On mine, if I leave the front hubs locked, and drive on tar I can feel the drag of the sideshafts, diff, and front prop spinning, so I generally slow down to around 30-40Km/h before shifting into 4H. After reading what Brett said " auto free wheel hubs should not be engauged above about 10km/h ", I am going to reduce my speed down a lot !!! It makes sense that speeding everything up in a split second to engage is not the right thing to do !!

I might be wrong (and I am not with my car, so I can't check it now), but I think it even says on the passengers sunscreen that you should change from 2 to 4H at a max speed of 40km/h.