Blog Review: 4WD Toyota Coaster Build up

Yeah mate, but most of the older ones like yours have been fitted with dana 60 diff in the front and regeared. I think they use the np205 transfer case though. Isuzu nps300 diffs are also a possibility too. It all depends on your budget and weight limits. I last used an Isuzu FTS800 and converted that to a motorhome

If their anything like the 2008 model up they are useless in slippery, muddy conditions even with mud terrains that have had the pressure reduced several times experimenting to try and help traction. We have them on mine sites a traction aid like a Lokka diff might help they need something.

I'm not too sure what the original blog was but here's my two bobs worth.
A few of us tour operators in Alice Springs, had these HB30 Toyota Coasters converted to 4WD. We found the later HB50 units were not as good for a number of reasons.
There was a company in Melbourne doing the conversion but I believe they've gone out of business. Their first units weren't built very well but by the time they closed shop, they had a good machine.
My first one was a 1988 LWB which I spent many years rebuilding. I ended up with 9.00 x 16 singles and a Chev. V8 diesel. I used the original gearbox and ran a short drive shaft to a Rockwell transfer case. A noisy unit but unbreakable. The rear diff assembly was out of a F250 2WD as it was a bit wider to allow for single tyres to be fitted.
The fuel tank has to be recessed to allow for the original front torsion bar suspension to be replaced with leaf springs which was necessary to fit a banjo housing out of a Dodge Ram. The front and rear diffs were Dana units. Oh yeah, the steering box has to be replaced with one from a Mazda T3100. I ended up with a magic vehicle that would "walk" anywhere! (I'll post some photos later)

My other Coaster was a 1992 which was almost the last of the HB30s. The original rear back axle, diff and 6 stud wheels, were retained which didn't allow singles to be fitted. It was ok in the sand but nothing like the older vehicle with the large singles. Both vehicles needed the rear roof pillars strengthened because of the heavy air cond. units in the rear of the roof and the front drivers door pillar also needed attention.

I've seen a company in Qld that also convert Coasters and they bolt a different transfer case directly to the back of the original gear box. I seem to recall they also had a rather complicated front suspension using coil springs.