Gearbox only works when hot.

[dokworm]

I've got an odd problem with the stock Nimbus auto gearbox.
When cold it will only change up to 2nd gear. Once it's hot it will change up through the whole range.
Anyone come across this before?

 

[Rockabilly]

Lack of fluid & presure in the valve body. You could screw clockwise the pres screw 1/2 a turn to tickle her a bit.
Cheers !

 

[dokworm]

I'll give it a go. Thanks!

 

[4piknup]

When was the last oil and filter change for the auto?
Is the trans oil still red or is it black?