Mitsubishi FWD F5A51: Jerky shift 3-->4

[Spetz]

Hi everyone,

I have a Mitsubishi FWD auto with the F5A51 transmission. Equivalent car to the US Diamante.

On very light to no throttle input, at the minimum upshift speed, the 3>4 gear shift is harsh, as if it does not allow any slip.

On partial throttle, or at higher than minimum upshift speeds this issue does not occur.

The fluid is about 30K miles, but still looks good.

Any ideas what this could be?
Or what to look at?
I should note that this is the original transmission and has 200,000 miles on it, but otherwise it behaves well without issues, shifts smoothly, no slip etc.

 

[dumkid]

What fluid are you using? What year Mitsubishi is it?

The v5a51 for rear wheel drive cars is picky about fluid, i don't know much about the f5a51

Maybe give jatco a call?

 

[Spetz]

What fluid are you using? What year Mitsubishi is it?

The v5a51 for rear wheel drive cars is picky about fluid, i don't know much about the f5a51

Maybe give jatco a call?

It is a 2003.
And normally I use genuine fluid, however as that is hard to find, I have used Castrol Transmax, which is the correct fluid for it