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LT230s what to do?


pugwash
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how common is it for LT320s to break? i've never seen one or heard of one.

but, if you stuck 350lb/ft through one would it survive? what could be done to strengthen them? they have a 2-pin diff don't they? are they a weak spot? does anyone do a 4-pin jobby? drilled input gear?

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Oh dear, my LT95 must be well overstretched then :blink:

Dont know about LT230, but the other gearbox designations are based on the size of the input shaft, or bearing, or sumthing, LT95 = 95mm compared to LT77 = 77mm, LT95 is the strongest box land rover/santana built, shame about the ratios :)

I know one of the engineers who developed the LT230 for TD5 so i can ask him about the torque rating when i get back to work in january

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I have always thought it to be about the strongest bit of kit that LR made out of the box. The Aussies seem to like it, as do the Bu****es accross the pond. I have never put more than about 400bhp and 500ft/lb through a standard one and that was with a TH700 to take the initial oooomph.

I have never had much luck with the LT95 over 350ish bhp/400ish ft/lb - snapped main shaft with 5.28:1 diff gears, and 35x15.50x15 Mickey T's. The Hybrid used to eat them when it had the Eales 4.6 in it, but both the RRC racers managed fine...

I know the R380 is named after it's max torque figure but I think the LT230 is named after something else - like the number of cups of tea drunk during it's design or the amount of oil (in Pints) it leaks in one year..

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Pugwash, LT230s are one of the few (actually very few) bits of drive train Land Rover ever designed that was really up to the job. As has been mentioned the centre diff is the weakest point but this can be improved. The standard setup is 4 pin but the cross shaft is split. Ashcrofts can sell you one for not a lot of money (about £150 for the cross shaft, a new set of gears to be on the safe side and a seal kit). Beware, though, that you can still blow a centre diff with one of these cross shafts fitted (I did) although I think the diff may not have been locked up when it happened (the diff lock warning light switch had failed). When locked up they're pretty tough - even the Aussies think they're OK!

The Quaife centre diff is a torque bias job and not cheap (£700 odd IIRC); its designed with racers in mind. I think unlocked it'll be stronger but locked up there probably won't be much to tell between this and a standard diff with a solid cross shaft.

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Dont know about LT230, but the other gearbox designations are based on the size of the input shaft, or bearing, or sumthing, LT95 = 95mm compared to LT77 = 77mm, LT95 is the strongest box land rover/santana built, shame about the ratios :)

I know one of the engineers who developed the LT230 for TD5 so i can ask him about the torque rating when i get back to work in january

I think it is the distance between mainshaft and layshaft in mm in gearbox's, bigger the distance, bigger the gears and bearings. Hence why the LT95 was regarded as a strong box, the LT85 stronger than the LT77 etc. R380 is the LT77 in disguise :ph34r: .... could just of called it LT77(suffix)x or something, could well be the distance from the input to output centres on the LT230 Transfer. I'll go and check!

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Don't you mean the R380 is simply a weaker version of the LT77, more prone failure when subject to low maintenance but with reverse in a nicer place :lol:

But the man at Land Rover marketing said it was "better and stronger and different...... ":rolleyes:

Yes it is 230mm between input and output on the LT230.

Regarding the original topic, I think its strength has a good reputation abroad, the yanks and aussies are happy to stick 350 small blocks and associated transmissions in front of them, adaptors are available :)

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the 2 1:1 LT230 s i have in the garage cost me £10 each from eblag and i got 2 free 3-speed autos with them!

i would have like to have used a BW as Dave says they are bloody easy to use and seem to create a shed load of traction- and you can't forget to put the centre lock in (a la James JST)

I do konw that Eliot Mez at www.mez.co.uk is putting about 450bhp (if not more) through his LT230, but then it is only a road vehicle and maybe doesn's suffer the trans shocks that off roading can create.

if anyone knows anybody that can supply adaptors to mate LT230s to yank autos then please shout- the only two i know of are advance adapt and marks adaptors- marks don't seem to have an amazing reputation and advance don't do what i need!

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Don't you mean the R380 is simply a weaker version of the LT77, more prone failure when subject to low maintenance but with reverse in a nicer place :lol:

i prefer reverse where it is in the LT77, better for rocking the car in low - i tend to go 2nd/rev to rock it. plus my R380 is carp & refuses second or reverse if you shift fast

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TF727- it's much underrated over here- i would use it myself except i fancy an overdrive box. it's a good choice for a V8 conversion for a landy- take off the adaptor ring and bolt up a MOPAR and away you go

I meant which auto are you going to run?

The LR spec 727 is weak compared to a proper 727

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TF727- it's much underrated over here- i would use it myself except i fancy an overdrive box. it's a good choice for a V8 conversion for a landy- take off the adaptor ring and bolt up a MOPAR and away you go

you can get overdrives for them, lock up, splitters and full manual control (the proper name escapes me) manual valve body maybe, bit that looks like a maze and controls shift patterns.

then you could run a hot rod style pistol shifter, muahhaah

sorry

i think the range rover didn't get such good internals as would normally be found in an A727 so maybe its not such a good place to start.

someone on outerlimits uses one in a racing discovery i think to good effect. only issue was keeping it cool enough, which proved to be quite a big issue i think. one that was resolved, however. i'm sure if you do a search for tf727 or a727 there you might find some threads.

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I meant which auto are you going to run?

The LR spec 727 is weak compared to a proper 727

it's not too bad- it's just because it's a light duty 727 and not the full bor "big block" version. I guess a rangie is light duty compared to some stuff

i'm using a 4L80e with a manual valve body and removal of the line pressure dependant shifts (ie box will shift to any gear even if it blows the box as opposed to standard which would stop the box from downshifting)

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I run a mod'd 727 in the hillrally car.

Reverse pattern, manual shift on a ratchet shifter with the 4 pin centre diff mod in the LT230 and no problems.

post-1563-1167435789_thumb.jpg

This box runs a seperate cooler at the front with its own fan to ensure it does not get too hot and, touch wood, all's been OK so far!

This setup has been run with a supercharged 3.9 and now just a "built" 3.9......

Bob

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LT230 can take a lot more torque than that - remember engine torque is multiplied by gearing in the gearbox (minus mechanical losses).

Regarding naming conventions:

LT stands for Leyland Transmission. When there was a Leyland group, the convention was to name gearboxes and transfer cases with the LT prefix, followed by the centre distance (in mm) between the mainshaft and layshaft for gearboxes or the centre distance between the input and output for transfer cases.

The LT85 was designed by Santana, for Leyland, when they were affiliated.

The R380 was designed after the demise of Leyland. The R prefix stands for Rover, and 380 is rated torque in Newton metres.

The weakest part of the LT230 is the 2 piece cross pins in the centre diff. There are aftermarket one piece cross pins (Macnamarra in Aus for example) which overcome this. Same problem with the LT95 centre diff.

Early LT230 had needle rollers in the intermediate shaft assembly. These are not as strong as the later versions, which have taper roller bearings. Same problem with the LT95, which has a similar intermediate shaft assy, if you push them, the needle roller thrust bearings fail. In Aus, there was a taper roller conversion for the army LT95, but I don't know of any conversion for LT230's.

Apparently, the gearing in LT230's has changed from time to time. When I ordered a 30% reduction gear conversion for my LT230, I remarked to Mal Storey about how low the pressure angle was for the LT230 gears. He said that they have changed the pressure angle and also the helix angle over the years.

In the early days of involute gearing (before gear tooth generating, cutting machines), the pressure angle was 14 degrees, but this was mostly replaced by 20 deg (with gear tooth generating cutters) and 25 deg has often been used many years when higher strength is required. The main downside of higher pressure angle is noise if the tooth profile and tooth to tooth accuracy are not of a high standard. The other downside of higher pressure angle is greater tooth separating forces, but should not be a design problem.

I have not had anything to do with the so called LT230Q (quiet gearing) transfer cases. From pics, diagrams that I have seen (could be unreliable), it appears to me that Rover have used a larger number of smaller teeth for some (maybe all) the gears. Although it will help to reduce noise, the strength will definitely suffer, if this is the the case. I suspect (again from pics I have seen), that this (more small teeth) also contributed to the reported (unsubstantiated) weakness of the 80% reduction gears that Dave Ashcroft had for a short time.

I would stay well clear of LT230Q if you want strength, unless someone can confirm otherwise.

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