Isuzu MSA gearboxes

What sort of selection problem?

When you checked the 'selectors' was it the forks in the lid you checked, or did you manually check the rings themselves?

The one thing I did that momentarily stuffed my ability to select gears was let the range selector (top shaft) drop into the box when I was making a new shift linkage. The drop allowed the finger on the end of the shaft to move out of position relative to the slot in which it normally sat.

Like the others above, I could only find the MXA manual. A bit odd really.

2nd and 3rd were Ok for a bit but notchy, then it got hard to get across to 4th 5th. Then I could get 4th but could not get into 5th so came home in 4th.
Took the top off but the selectors worked OK then. Sliding across and back and forth nicely off the box but when put back on still would not move far enough.
I have to look a bit further:(

Keith

Lying awake thinking about this the worse it gets.
With the gearbox and transfer boxes in neutral should not I be able to rotate some of the gears in the MSA.
Levering with a screwdriver on the edge of the box none want to turn.
Maybe the handbrake is jamming but thats too easy, with the T box in neutral that would not affect it would it?
It seems as if something has seized and as I have an adapter mating to the LT95 it may be there.
In the morning I will jack up a wheel and see if anything will turn. I dread taking out the box as the truck is too heavy for the 4 poster and it means crawling around under again. Getting to old for this.

Keith

Quote:

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Originally Posted by 123rover50

Lying awake thinking about this the worse it gets.
With the gearbox and transfer boxes in neutral should not I be able to rotate some of the gears in the MSA.

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Sounds like you're trying to turn the motor over. You'll need someone to put their foot on the clutch.

Wonder if you've ended up with reverse and a forward gear engaged at the same time while the selecter was off.

Steve

What are first and reverse like for selection?

Minor note, I found that when the box is not being driven (engine off stationary vehicle) it is a bit notchy at first when working through all gears from reverse through 5th, however after a few attempts everything lines up inside the box and shifting through the sequence is smooth.

Chase up any other suspicions by all means, but maybe take the top off again and this time see if you can move the rings by hand. Probably obvious but make sure your selectors are lining up with the grooves.

Did this difficulty in changing come about after any event or maintenance or has it been gradual?

I posted a photo of the top off my gearbox on my RRC thread under the isuzu 4bd1 section if it helps (need a few more views to get it to 10,000 :)).

All the gears on the shaft seem to have moved towards the front.
The big gear at the back now has about 10mm end play.
Perhaps this is why the selectors are not lining up and perhaps selecting two gears at once.
I have ordered a WSM from Isuzu . Have to buy the whole set just to get the MSA5G.
I have forgotten what holds it all together. Perhaps the big nut has come loose.
Looks like I will have to pull the Tbox anyway to see whats happening.
Another MSA 5G box I pulled the top off has bugger all end play in that big gear and the selector rings can be moved by hand 4th to 5th and back etc. On this box in the truck I cant, everything is tight.

My gold plated WSM arrived from Isuzu.
Interesting reading.
I cant remember if I bought a new drive coupling nut when I did the T,box conversion. I suspect I did not.
The WSM states a new nut must be used.
Now prior to 1998 boxes the nut was not staked, just tightened to torque.
The 1999 model had one caulking groove in the shaft to stake the nut into.
They must have had trouble with the nut coming loose as from 1990 on there are two grooves in the shaft to stake the nut into and instructions are given how to do this properly.
I have not pulled it down yet but I suspect the loose nut is my problem.
Looking at my spare boxes , one has one groove and the other has two.
The latter looks the better box so I think I will swap it over for the one that is in it now. The trip back with the synchros hard on has done them no good I imagine.

Keith