Ideal LT230 for 4bd1T?

[THE 109]

From what I've found so far the 1.003:1 ratio out of an auto RR would be best suited to the engine,but I'm not sure if the input gear is crossed drilled
for better lubrication like in later units.Can someone explain which vehicles had a LT230Q as they seem to be stronger and quieter?
Aslo would the 1.003:1 gears fit the later transfercase?
Cheers Eric

[Dougal]

Ashcrofts can build you a modified 1.003 LT230.
I run an LT230R, only had it in for 15,000km and it's back out to fix some leaks (old, hard orings) There's no sign of input shaft wear in the last 15,000km but the LT230T which had done about 500,000km didn't heve any wear either.

[Bush65]

From what I've found so far the 1.003:1 ratio out of an auto RR would be best suited to the engine,but I'm not sure if the input gear is crossed drilled
for better lubrication like in later units.Can someone explain which vehicles had a LT230Q as they seem to be stronger and quieter?
Aslo would the 1.003:1 gears fit the later transfercase?
Cheers Eric
The input gear can be drilled with difficulty. There is a part that can be added to help with lubrication.

From what I can find (not seen) the LT230Q has smaller gear teeth so would be weaker than either R or T versions. They were fitted to disco II's - I don't know what years.

[Bearman]

There is a part that can be added to help with lubrication.


Red Rocket makes a modification for lubricating this gear. Send him a PM.........Brian

[Dougal]

There is a part that can be added to help with lubrication.


Red Rocket makes a modification for lubricating this gear. Send him a PM.........Brian

Like the rear cover plate that Ashcroft sell?

[THE 109]

Thanks for the replies everyone,the aftermarket plate for the lube fits in place of the pto cover if I understand correctly.
That won't suit me as my winch runs off the pto.
So the R and T versions are the ones to look out for then,although to get the 1.003:1 gearing I'd have to get a gear set and make it fit.
Am I on the right track here?
Cheers Eric

[Dougal]

Thanks for the replies everyone,the aftermarket plate for the lube fits in place of the pto cover if I understand correctly.
That won't suit me as my winch runs off the pto.
So the R and T versions are the ones to look out for then,although to get the 1.003:1 gearing I'd have to get a gear set and make it fit.
Am I on the right track here?
Cheers Eric

The R box fitted to the 3 speed rangie auto was 1.003:1 high ratio. I have one of these.
The 1.003:1 T box is rare. Ashcrofts can do it and there may be Isuzu county LT230's with that ratio.

If you're running larger tyres you may not need the 1.003 high range. That'd make it really easy.

[THE 109]

Thanks Dougal,
It's all becoming clearer now.
Eric

[justinc]

The R box fitted to the 3 speed rangie auto was 1.003:1 high ratio. I have one of these.
The 1.003:1 T box is rare. Ashcrofts can do it and there may be Isuzu county LT230's with that ratio.

If you're running larger tyres you may not need the 1.003 high range. That'd make it really easy.

I chose to run a LT95 with .996:1 High range and 33" tyres. but if I had an LT230 and R380 or LT85 Santana, I would run the 1.2:1 gears and 33"tyres.

The 'Q' gearset isn't as strong, I have seen chipped/ damaged ones more than the early 'coarse' gears, even in Td5 D2's.

JC

[THE 109]

Justinc
The idea is to use an isuzu 5 speed and 235/85/16's if I can get it all to fit lengthwise,as I can't push the transfer back because of my winch.
Eric

[Dougal]

Justinc
The idea is to use an isuzu 5 speed and 235/85/16's if I can get it all to fit lengthwise,as I can't push the transfer back because of my winch.
Eric

The Isuzu engine and box is shorter than a landrover engine and box. I have a 3" spacer plate to keep the transfer in the original position.

[Bush65]

Thanks to the short bell housing, you should have enough room for an adapter between the Isuzu 5 speed and LT230, without pushing the LT230 back.

[THE 109]

If that's the case I might push the whole lot back a little for more room up front,of course that depends on the adapters thickness.Then the air filter probably won't fit behind the engine if I do that:(
I will just have to try it and see what can be done.

[Bigbjorn]

The 1.003 ratio was standard with the 4BD1 and LT85.

[justinc]

The 1.003 ratio was standard with the 4BD1 and LT85.

That is apparently true, BUT mine was an ex 1988 110 and had a 1.2:1 High range and LT85.

JC

[Albert]

I got a LT85 from a V8 & bought a set of gears that I ws told was standard for this set up. I dont know the ratio but it is way too high. Third gear (no tacho) runs to 100km/h, 1st gear is a pain to start with a bit of load or uphill.
When I work out my ratio I will change it.
Can this be done without pulling the box/tc out?

[mox]

Probably of interest to those who have an LT230 with 1.003:1 high:
I have one of these. Was after a 1.2 box which would be better for my purposes than 1.4 in a Defender. It was pulled out of a Discovery but serial no indicated it came from an earlier Rangie with 3 speed Torque Flite auto.

Did some looking thinking and measuring. Then got a new input gear cut that drives directly onto the high range gear of the cluster, similar to the layout of Series Transfer boxes. 22 teeth to 44 instead of the standard 26 tooth input to 41 tooth middle gear on cluster. Overall ratios 1.27:1 high and 4.21:1 in low. ie Nearly as fast as Discovery high range and nearly as slow as Maxidrive 30% reduction in low. Cost of gear design, cutting and hardening a bit less than Maxidrive low gear set. Did not include teeth for PTO dog clutch on it. This would have added the order of $200 for something that very few people use. Holes to allow oil to lubricate the spline were included. The original gear did not have any. Probably it and the short input shaft from the Torque flite had been replaced as silastic on gasket faces indicated box had been taken apart since original assembly and splines are in perfect condition.

With my present priorities, will probably be 3 months before I get around to assembling box and installing it. Intend to post some photos then.

Mick

[Bigbjorn]

That is apparently true, BUT mine was an ex 1988 110 and had a 1.2:1 High range and LT85.

JC

What vehicles used the 1.2? Yours may well have been changed out.

[Bearman]

I got a LT85 from a V8 & bought a set of gears that I ws told was standard for this set up. I dont know the ratio but it is way too high. Third gear (no tacho) runs to 100km/h, 1st gear is a pain to start with a bit of load or uphill.
When I work out my ratio I will change it.
Can this be done without pulling the box/tc out?

Hi Albert,
Yes you can change out the gears without removing the transfer case. Pull the intermediate shaft and change the high range gear on it and then remove the centre diff assembly and change out the high range (small gear) on it and reassemble. An afternoons stroll in the park........Brian

[Dougal]

With my present priorities, will probably be 3 months before I get around to assembling box and installing it. Intend to post some photos then.

Mick

I look forward to it.
I'm very happy with my 1:1.003 high range with 3.54's, 29" tyres and .0.77 overdrive. Even if I get bigger tyres later on (will require a taller garage) I won't be going lower in gear ratios, I've got plenty of torque for 5th gear passing duties.

[Bush65]

Probably of interest to those who have an LT230 with 1.003:1 high:
I have one of these. Was after a 1.2 box which would be better for my purposes than 1.4 in a Defender. It was pulled out of a Discovery but serial no indicated it came from an earlier Rangie with 3 speed Torque Flite auto.

Did some looking thinking and measuring. Then got a new input gear cut that drives directly onto the high range gear of the cluster, similar to the layout of Series Transfer boxes. 22 teeth to 44 instead of the standard 26 tooth input to 41 tooth middle gear on cluster. Overall ratios 1.27:1 high and 4.21:1 in low. ie Nearly as fast as Discovery high range and nearly as slow as Maxidrive 30% reduction in low. Cost of gear design, cutting and hardening a bit less than Maxidrive low gear set. Did not include teeth for PTO dog clutch on it. This would have added the order of $200 for something that very few people use. Holes to allow oil to lubricate the spline were included. The original gear did not have any. Probably it and the short input shaft from the Torque flite had been replaced as silastic on gasket faces indicated box had been taken apart since original assembly and splines are in perfect condition.

With my present priorities, will probably be 3 months before I get around to assembling box and installing it. Intend to post some photos then.

Mick
The down side of this is that you effectively halve the life of intermediate gear. That may or may not be an issue.

Gear ratings are based on strength and wear for 12000 hours. Gear strength is for fatigue strength of the teeth, gear wear is basically for pitting of the surface of the teeth flanks.

Because load is applied twice to each tooth on every revolution you halve the fatigue life and double the load cycles for wear.

If the gears were to be designed for this in the first place then the material and hardness of the intermediate gear could be selected to suit.

Generally the pinion (small gear of a set) has the lowest strength and wear rating if both gears are manufactured from the same material, so usually the pinion is made from higher strength material and the larger gear is made from lower strength material so their ratings are more or less matched.

[mox]

I look forward to it.
I'm very happy with my 1:1.003 high range with 3.54's, 29" tyres and .0.77 overdrive. Even if I get bigger tyres later on (will require a taller garage) I won't be going lower in gear ratios, I've got plenty of torque for 5th gear passing duties.

What motor are you running?
In Defender with 300Tdi, faster high fifth and /or overdrive would be good for some high speed work. However faster gearing after the gearbox would be a disadvantage for some situations Land Rovers are used for with first and reverse high being too fast. Reckon for my purposes going to 1.003 is overdoing it.

The six speed gearbox in combined with approx 1.2 high in Pumas have slightly lower first and reverse gears and higher top than R380's. So probably owners will feel less inclined to use non standard transfer and diff ratios.

Mick

[mox]

The down side of this is that you effectively halve the life of intermediate gear. That may or may not be an issue.

Gear ratings are based on strength and wear for 12000 hours. Gear strength is for fatigue strength of the teeth, gear wear is basically for pitting of the surface of the teeth flanks.

Because load is applied twice to each tooth on every revolution you halve the fatigue life and double the load cycles for wear.

If the gears were to be designed for this in the first place then the material and hardness of the intermediate gear could be selected to suit.

Generally the pinion (small gear of a set) has the lowest strength and wear rating if both gears are manufactured from the same material, so usually the pinion is made from higher strength material and the larger gear is made from lower strength material so their ratings are more or less matched.

The above factors are undoubtedly important with reasonably high loads and much more so when they approach or exceed that designed for, especially shock loads. However, I doubt it is an issue with an LT230 unless considerably more torque is applied than can be generated by a standard Rover motor and gearbox. Or in Series transfer boxes, where the input gear drives what is also high gear on the cluster like my LT230 modification.

Reports of these transfer boxes being busted seem very rare compared with those for Land Rover gearboxes, diffs and axles.

When there is a large factor of safety regarding gear strength, other than rapidly wearing them out and /or overheating by running without oil, a major destroyer of gears is failure of bearings causing them to not mesh properly. Normal loads can then then cause very heavy wear and /or stress and breakages.

In many gearboxes the cost of a complete set of new bearings may be similar to the price of one typical gear in it. Therefore if there seems any risk of bearing failure, it is good insurance to replace them.

One of the rare instances I have come across gears breaking - after relatively short periods of heavy load is final drive bull gears and pinions in my header (ie combine harvester). This was harvesting summer (growing ) crops in heavy muddy conditions in winter in the early 1990's. (Seems to me that will be our turn to have wet seasons and floods again in Murray Darling Basin in not too distant future despite record recent droughts. One effect - more uses for Land Rovers!)

Header was on rice tyres which were larger than standard ones on the machine and treads are much longer and further apart than tractor pattern. Loads encountered would have been far in excess of those considered by the designers. However, it is interesting to note that most of the trouble was with the left side final drive. Probably because the gearbox was close to it , with only a short drive shaft. The long right side drive shaft would have flexed a lot more, acting as a shock absorber to reduce fatigue and failure in final drive gears.

Note regarding Land Rover axles which are prone to breakage - usually next to the spline, "waisted" ones where the diameter of the axle is similar to the inner rather than outer diameter of the spline seem to be more reliable. They are more inclined to flex over their whole length and less likely to develop fatigue in one or two areas.

Mick

[Dougal]

What motor are you running?
In Defender with 300Tdi, faster high fifth and /or overdrive would be good for some high speed work. However faster gearing after the gearbox would be a disadvantage for some situations Land Rovers are used for with first and reverse high being too fast. Reckon for my purposes going to 1.003 is overdoing it.

The six speed gearbox in combined with approx 1.2 high in Pumas have slightly lower first and reverse gears and higher top than R380's. So probably owners will feel less inclined to use non standard transfer and diff ratios.

Mick

I'm running the Isuzu 4BD1T. Roughly twice the torque of a 300tdi.
I'm also running the Isuzu gearbox which has a spread of 0.77-5.8, reverse is similar to first.

I don't use low range much. Even boat launching is fine in high.

Rough comparison with the R380, my second gear is similar to it's first gear (3:1 for me, 3.4:1 on 380) but 5th ratios are almost identical.

The puma 6 speed has a slightly higher top gear and slightly higher first gear than my Isuzu, but the overall gear ranges are similar.
Puma 5.44/0.74 = 7.35 spread.
Isuzu 5.8/0.77 = 7.47 spread but one less gear.

Using this webpage for reference:
http://www.expeditionlandrover.info/gear_ratio.htm#seriesxfer