Thread: Ultra Low Range Gearbox

What about one of these?

http://www.ashcroft-transmissions.co...tegory_12.html
and more on same -
http://www.eastcoastrover.com/Underdrive.html

Sounds like you want a set of rock crawler gears. Or maybe air down the tyres to dip it in and out of the water.

Have you actually had trouble yet? I'm guessing not or you wouldn't be questioning the dollars, just reliving the embarrassment and punishing your credit card.

That is a bloody big boat.

Cheers,
Simon

I've only retrieved and launched the boat twice yet, it's a new arrival and so is the subcylonic winds and rain we now have in Far North QLD. The retrievals where puzzling. The first time was easy, a little revving in low range and it was simple. The second was an absolute b*tch. I revved a bit, let out the clutch and got no forward motion but almost stalled. Finally got under way but had low power. Talked to the mechanic who states that as the second retrieval was done with a relatively cold engine (had only been running for 3 mins) I wouldn't have had enough power. Also I engaged diff lock 2 metres from the waters edge and thus may have not really engaged it despite the light being on, thus may have been spinning a wheel. I'm planning on retrieving next time with a well warmed engine, but if necessary may get low range modified or possbily 15 inch tyres. It's certainly cheaper than buying a tractor!
Yes the boat is large ... I get quite a few comments re am I trying to compensate for something. The reply "well your missus doesn't think so" normally quietens most people !

These units look good. I think I'm running a 380 gearbox, not the LT230 however I'll need to check my manual and find out ! (Can't get to the car in the front garden at the moment without getting soaked)!!

your landrover comes with the lowest of the low low range gears fresh out of the box... IF you cant haul something with that in 1 low going to a lower ratio will in all likely hood result in one of 4 things happening

1. having the wheels break traction from too much torque and not enough grip (especially on wet boat ramps)
2. breaking the diff, axle or propshaft
3. physical damage to the towing equipment on the vehicle
4. spinning the rim inside the wheel

Most rock crawling gears are used not for the torque multiplication factor but the lower speed that they offer.

An auto offeres the best torque delivery and due to the TC more torque for start off. The number of times Ive seen people spinning the rubber on auto equiped vehicles (and overpowered manuals) trying to pull boats up boat ramps is just stupid. at one stage I made a good weeks drinking $$$$ from parking a winch equipped rover at the top of the local boatramp whenever it had been raining and for $5 a pop Id winch the stuck vehicle up the ramp.

Letting the tyres down is not a smart option.. The rims get wet then when you apply the power they spin inside the rubber, if your lucky they stay up, unlucky they go down then can be reinflated with the onboard compressor and really unlucky you dont notice it till youve ripped the bead to shreds then have to be recovered out or change the tyre with the trailer on the back to get the boat out.

The smartest solution Ive seen is a dolly for the front of the trailer and a winch or tow rope from the vehicle to the trailer, this way the weight of the vehicle is up on the flat and is less to over come.

The next best would be once the boat is on the trailer and secured at the bow and stern (put your tie down straps on bouys so they float past the hull and can be gaffed) backing the whole lot down the ramp till the boat floats part of its weight then go forth, the momentum gained is usually enough to get the motor up to full steam and your not trying to over come all the inertia uphill.

but be careful.. I saw one guy do this and get too far down the ramp...the boat caught some sideways action pulled him off line and off the boat ramp into the briney....

or like a guy in Perth this week, well known identity reversed down ramp with boat on, lept out of cruiser, didn't have it in park or handbrake on, cruiser and boat reversed into marina till cruiser submerged to roof line.

apparently done while hob knob luncheon on at marina so plenty of photos taken of event

could you have somebody in boat to assist in getting while the prop is still in the water than cut the engine once moving

FYI

Defenders should have the LT230 transfer case. Maxi-Drive Engineering make a conversion for your LT230 to reduce the low range by 30% or by 49% (2 options).

Originally Posted by weeds

could you have somebody in boat to assist in getting while the prop is still in the water than cut the engine once moving

thats not bad either, youd want a pretty good bow mount on the trailer tho