Thread: Isuzu MSA Gearbox to LT230

Isuzurover, as you say Sheldon can clarify as to heat treatments.

In regard to mating the MSA to LT230 transfer case I'm interested in the dilemma of going fully customised, or partially customised. Vern's discussion about retaining the 10 spline and easy field serviceability is of interest to me.

Just to refresh the memory, the standard LRover spud shaft is called the RTC5090, 25 spline female one end and 10 male spline the other end; it mates with the standard 10 spline input gear in the LT230 t/c. Sheldon in essence is proposing to beef up these two units by replacing 10 splines with 32 splines.

Sheldon is the following worth considering?

Take the 24 spline output shaft on my MSA for example. Mate to it a spud shaft terminating in 25 spline male. From this point onward 3 choices.

1) mate onto the first spud shaft a standard FTC5090 10 spline spud that can then terminate in the standard 10 spline input gear (your inbuilt weak point but easily replaced part for peace of mind)

2) mate onto the first spud shaft a second spud customised by you terminating in 32 splines; then to an input gear customised by you to 32 spline.

3) mate onto the first spud shaft a second spud customised by you to also terminate in 25 splines; then to an input gear customised by you to 25 spline.

The two spud shafts, what ever choice in the second, mounted sequentially should be able to be secured using one bolt, subject as you say to tapping the MSA output shaft centre to suite.

This way if you buy the proposed 32 spline arrangement, or a 25 arrangement, but are unlucky enough to break it you can install the standard cheap 10 spline set you carry as spares, while waiting on another custom 32 or 25 set - provided the first spud has not broken at the 25 spline.

Down side is having weaker 25 spline before the 32; but upside is removal of ten spline. Maybe, instead of 25 standard and 32 custom, go 25 standard and 25 custom? Any way of strengthening the 25 on the first spud making the second spud 25 slightly weaker by comparison? A compromise between ultimate strength vs improved strength, spares costs, ready availability and field servicing. Hope this is making sense.

Of course the counter argument will be forget mucking about with two sequentially mounted spud shafts - that ultimate strength design wins out - and Sheldon will carry spare stock. In which case my logic says buy two of Sheldons fully customised units, one set as spare. Any idea on cost of 32 spline spud shaft and 32 spline gear for the 24 spline MSA, just in case I ever do my Outcast unit?

Slow progress Vern, what with this RRC project and keeping 3 disco 1's rolling. Fires in the district so spent half of today slashing boundaries! Just recently got the industrial sewing machine fired up to make new quad bike seat cover, spanner rolls, as practice for reupholstering the RRC seats (an no, won't be croc hide, just some easy care something)

RRC, all the running gear is in place. No body on yet - rust to deal with - plus been having thoughts I can't resist about building a chassis rotisserie come body lift system come sand blasting booth.

Last little exercise on the RRC was making the gearstick system. Started out measuring all the photos I could of Sheldon's and the gearbox cover; learnt basics of FreeCAD so I could make some drawings and work out leverage ratios, points of interference etc; cutting and shaping all the flat bar. Redesigned the shift mechanism at the bottom of the gearstick (tested my milling skills) - didn't use Sheldon's idea of the adjustable rod. All works nicely, but the exercise did give me reason to think of another way of doing the thing. Anyway...

Sheldon, where are you up to in terms of photos of the bits and their installation examples, specifications, pricing on the spud shaft 32 spine arrangement? Is it true that the MSA output shaft can be drilled and tapped quite easily using standard high speed steel stuff?