Offroad-Express

I know these gearboes have a bad rap....
This box has been rebuilt before also.

Problem:
As of late my terrano hasnt been selecting 2nd gear. (Intermittently)

Description:
So i drive alon it holds 1st then skips 2nd into 3rd when i get enough speed up.

I've checked the fluid level and condition - OK
If i use the "Hold/Power" switch and use "Hold" the shift is much softer and selects 2nd for a instant then slides into 3rd.

This is obviously not normal....
Any ideas? can anyone link me to a repair manual or info?

Cheers

I dont know why, but mine slips between gears, revs go up between changes. I think its on its last legs..... a shame terrano boxes are so shit