High torque manual gearboxes

[Emolloy93]

I've got an American truck engine sitting in my shed which is just begging me to swap it into an offroader to make a stupid weekend toy, but the problem is it makes about 300lb-ft at 1200rpm and heads up to 425lb-ft at 3000rpm.

I know there's a huge number of autos that could take that no problem, but I'd prefer to have a manual for the fun of it. So far my searches for gearboxes that could take the torque seems to be limited to big American pickup gearboxes which are hard to find here or luxury diesel cars like BMWS but the ratios aren't great for low range.

Anyone got any suggestions for a suitable gearbox that won't just blow up? Bonus points if it's got a transfer case as well.

[Snow and Rocks]

Obvious answers are the boxes fitted to straight six Land Cruisers and Patrols?

No idea on the technicalities (or cost...) but they've both got a reputation for strength and durability and come from the factory attached to pretty grunty engines that are easily and successfully tuned.

[Gassmi]

You want an NV4500. That’s the answer. Takes the torque, parts are around, and bolt a divorced NP205 behind it. Heavy but unkillable.

If that’s too hard to find then an LT95 out of an old Range Rover or 101. Crude as hell but strong. Ratios are rubbish though.

Avoid BMW and car boxes. They’ll shat themselves first time you actually use that low end torque.

[InitialDave]

First question is whether you have a transfer box already, and I assume it's a divorced one if so?

And how much length do you have to play with?

I think those are the factors which will narrow down the selection a bit.

Can't see an issue with a car-derived gearbox myself, provided it's able to take the torque. Is your preferred transfer case and axles reasonably well served with different ratios being available to change things to suit?