Thread: strongest box

Originally Posted by JDNSW

Just a couple of comments on the history of the boxes discussed.

As I understand it (and correct me if I am wrong) ;

The LT77 and R380 are both evolved from a 1940s four speed Jaguar box, with fifth gear an add-on. The latest versions are handling powers and uses that the original designers would not have dreamed of.

By contrast, the LT95 was a new design (as far as I know from a clean sheet) in the mid sixties, intended for a gun tractor (101) with a powered trailer, but also targeted at the planned Rangerover.

John

I can believe the 101 box development story John, the shafts and bearings in these are just immense. It is also a very, very simple transmission

JC

Yes John AFAIK the lt95 was a new box. And since the Range Rover market unknown, and only enough budget for one new box design, they felt the 101 market success a lot more certain so that influenced the design more.

Originally Posted by justinc

I can believe the 101 box development story John, the shafts and bearings in these are just immense. It is also a very, very simple transmission

JC

Not just a story - this bit of my statement is quite well documented. The Rangerover, I think, actually was in production first, but the 101 was designed at the same time, so the box needed to meet both requirements - and the 101 was the one that dictated the strength. It also dictated the unique power takeoff provision, giving an output shaft with the same speed as the prop shafts, for the powered trailer in both high and low range. And used, of course, in the Perentie 6x6.

To complete the story the Series gearbox was introduced in 1932, when Rover moved up market, selling to middle class buyers, in a strategy very reminiscent of the Discovery story, after failing to compete with Morris and Austin in the mass market. It had synchromesh added to the top two gears in the late 1930s, I think, earlier relying on freewheel for easy gear changing, and full synchromesh with the Series 3 (actually some very late S2a).

John

Originally Posted by JDNSW

Not just a story - this bit of my statement is quite well documented. The Rangerover, I think, actually was in production first, but the 101 was designed at the same time, so the box needed to meet both requirements - and the 101 was the one that dictated the strength. It also dictated the unique power takeoff provision, giving an output shaft with the same speed as the prop shafts, for the powered trailer in both high and low range. And used, of course, in the Perentie 6x6.

To complete the story the Series gearbox was introduced in 1932, when Rover moved up market, selling to middle class buyers, in a strategy very reminiscent of the Discovery story, after failing to compete with Morris and Austin in the mass market. It had synchromesh added to the top two gears in the late 1930s, I think, earlier relying on freewheel for easy gear changing, and full synchromesh with the Series 3 (actually some very late S2a).

John

Sorry wrong use of words, 'story' meant as I have heard and read about it, so yes well documented but I was in 2 minds as to what came first, the RRC development in the late 60's, or the 101FC around the same time.

JC

Originally Posted by justinc

Sorry wrong use of words, 'story' meant as I have heard and read about it, so yes well documented but I was in 2 minds as to what came first, the RRC development in the late 60's, or the 101FC around the same time.

JC

Yes, although the first tries at a Rangerover design go back to the early sixties, and the 101 first appeared in 1972, the 101 was well into the design stage by the time a gearbox decision had to be made for the Rangerover - and since no Rover gearbox could handle the V8, once the decision to use that engine was made, it would have to be a new design, and so would the one for the 101. Since Rover could not afford to design, test, and tool up for two new gearboxes at the same time, obviously the same one would have to be used - and while the 101 needs dictated the strength of the box, it is likely that without the Rangerover requirements, the design would have been a lot more agricultural than it turned out.

John

Originally Posted by justinc

The LT95 is a mans transmission, the R380 a toy, the LT77 an even more insignificant toy. The LT85 is reasonable, but it too has some issues...


JC

What you gunna call the MXA ? May be BHP

Originally Posted by justinc

And baby bear said, "....And its sleeping in Myyy bed"


That MT82 seems like a good unit, use the CORRECT oil, and change at reasonable intervals and it should serve well. I am a little perplexed at the size of the Puma clutch, although NEVER have I had one slip OR heard of it (even heavily loaded chipped ones), they are a smaller diameter than the Td5 one by a long way. The clamping force must be way higher, not noticeable at the pedal I think due to the design of the slave cyl etc.

JC

They are having problems with the clutch too JC,most pre 2010 but they have been updated.Mine was changed for some reason,the new one feels no different to the old one.I couldn't go back to a four speed with 2 foot of stick throw,I struggle with the R380,there's nothing better than a close ratio six speed. Pat

Originally Posted by PAT303

They are having problems with the clutch too JC,most pre 2010 but they have been updated.Mine was changed for some reason,the new one feels no different to the old one.I couldn't go back to a four speed with 2 foot of stick throw,I struggle with the R380,there's nothing better than a close ratio six speed. Pat

Certainly are Pat, have fitted many of the latest design from LR/Ford which seem to have cleared up the rattles and the odd plate centre failure. They don't seem to slip though, but have mechanical/ design issues.

JC