Having found another owner of a J26 in japan who can read & write basic englich - tons better than my Japanese - I have found that my 4 speed gearbox is a M140.
These are modified 3 speed T90 units on the Willys CJ3B.
Splines = 10, Teeth = 29.
The problem I've got is it's often difficult getting 1st and 2nd gear (also the Warn OD tends to jump out of direct into neutral but I guess thats another kettle of fish).
The chap in Japan is offering to send me a parts list, diagrams and if the parts needed are small ones then parts too.
However, do you helpful folk know of anyone within striking distance of Tewkesbury who can look at the problem, tell me what's causing it and, on the basis that parts are obtainable, rebuild the box for me?
I'll pay the going rate for the work involved for both diagnosis and rebuild.
As I use my Jeep daily this is something that I'm going to get done this year rather than next month as I can work with the problem by shuffling between 4 speed and OD gears when the problem occurs.
e.g. pulling away in 3rd with Direct engaged when 1st and 2nd refuse to play ball
.
All help will be very much appreciated,
Bernard