Thread: MSB 5M to LT230

Very interesting. But I'm curious why you've started with a MSB box? They're a lot smaller and presumably weaker than the MSA.

I found some specs on the MSB-5S, it has 88mm shaft centres compared to the 97mm shaft centres on the MSA and 100mm centres on the MXA.

I don`t have the standard Isuzu diesel. I have the older 4bb1 non turbo. The gear box is normally behind a 4bc wich is slightly less in capacity, 4bb1 is 3.6. The 4bc is 3.3, but both have the same horse power, so I`m guessing about the same torque. So if the gear box is ok for a 4bc it should be fine for a 4bb1. The gear box I have read is rated to 275 torque.
Cheers Hall

That MSB-5S I mentioned above is fitted to a 4BC2 powered NPR in the family business. The only problem it ever had was eating a rear output seal, even after being run dry for a few thousand km it's suffered no ill effects.

It's a good gearbox and a lot more compact than the MSA.

Interesting that you mention the rear output seal leaking. The gear box I have also shows signs of leaking. I`m guessing that the tail shaft hand brake would not help. If the handbrake drum has any vibration or out of balance it would shorten the seal life real quick. This potential problem will not be a problem as the hand brake goes to fit the transfer case.
Cheers Hall

This one didn't just leak, the seal came apart with the lips going around on the shaft and casing still in the housing. This was around the 120,000km/20 year mark. I replaced the seal and it's good 5 years on.

The seal is the same part in MSA and MSB boxes.

Well it is all done now and working. Forget the google sketch. Was all wrong with that idea. Now it is a whole lot simpler. Took about a month or more too long due to my first plan of conversion. Once I realised how the gear box selected the gears internally in relation to to the two leavers on the out side the conversion moved along smoothly. Well not real smooth, was a basic plan with a fair bit of hmm maybe not that way and a bit of but scratching, navel gazing and just a little bit of deep thought. Once I got the gear box bolted to motor. I had to modify one lever. Also made a mounting bracket for the left side of the transfer case at this stage. Took the landy for a test run to day. Had only a minor issue with selecting 2nd. Only had to adjust the length of one link and all was ok. Was quite surprised how well the ute goes now. There is one particular hill that I travel up and down a lot. Before the conversion the ute used to get up this hill ok but would settle on about 70 k`s and not much faster. Now it accelerates up the hill. Got to like a gear box that is made for the motor. So now I will have to give a longer test around Gembrook/ Bunyip or Toolangi.
Cheers Hall

Looks like a Mk3 Zephyr floor shift

I initially used cable shift with my MXA 6 speed, but didn't like the cable route and small bends that resulted from using what I had at hand.

I started modifying the cable gear shifter that I was using to replace the cables with links.

In the meantime I have been distracted with moving and much other work, but this allowed time for a much better solution to come to mind - partly influenced by the grubbs kit, but far simpler. I plan to:

Weld a substantial sleeve to the side lever for the gear stick - the stick can pivot in the sleeve for the left-right shift, but when moved forward-back the stick will turn the lever in the box to select gears (or neutral).

Re-weld the top lever so that it faces to the rear and make a link to go between this lever and the gear stick so that when the stick is moved left-right it will turn the top lever to select gears.

I have dummied it up and it works fine, just have to find some time ...