Loco transmission

Oops Duncan, my brain translated 125Hp for 125cc and just thought the replies were a bit of overkill. Time to have a cold shower.

Bob

Would a continuously variable transmission (CVT, like those used in DAF cars of old) be of any use? I believe they work equally well in forward and reverse. Don't know if they could handle the torque, though.

Rob

Duncan - your application sounds similar in many ways to that of an "aircraft tug" or push back tractor. Might be worth looking to see what they use for transmissions. Spares should be available, and I've seen one company in Ireland selling second hand tugs.

Maybe a transmission from a forklift would do the job? I'm pretty sure I've seen them being pushed/towed around so indicating they may have a 'neutral' position on the transmission.

Just an update : I found someone who knows about powershift torque converter gearboxes, it seems that they cannot be towed either. The pump which lubricates the gearbox is driven off the engine, so whilst you'll get away with towing a short distance 7 miles would wreck the box. Back to square 1. Now looking for a 1:1 drop box that you can put out of gear. I've tried marine, they don't tend to have 2 output shafts. The other option is a bypass and electric boost pump on the existing hydrostatic, but we'll out of my comfort zone.

Duncan, try a Landrover transfer box, high, low and neutral with 2 output shafts, one for front axle and t'other for rear. I suspect most 4x4s have a similar arrangement especially if they've got a "north-south" engine arrangement rather than a transverse.

Should have thought of that, thanks. I have 750 Nm torque, which doesn't sound too distant from a land in a low gear.

Bedford or Austin drop box mixed with a hydraulic drive might be an answer ! Hadn't bothered to mention Land Rover as I thought any ideas as to a clutch had been ruled out. Reynolds - Boughton may be a name to check out. They supplied alsorts of transmission for many military vehicles. Noel.

Bedford or Austin are going to be old and obsolete, but it's a good starting point. I don't see why I can't couple the hydraulic motor to a land or similar transfer box as long as it can take the torque.

The boost pressure on the cranes I work on is around 14 Bar, similar setup with swash pump and motor, you need to provide enough oil to replenish all leakage across the circuit, I doubt a battery pump system would keep up for long. A small lister & pump for emergencies would work.

That's the worry, disengage gearbox is favourite if I can find one. I've got some more numbers to try tomorrow. The Bedford boxes were made by David Brown many years ago and they are still in business making transmissions for AVVs, so here's hoping