Stuck in 4th gear in D when pulling away

[planets]

Hi all. I’m having an issue with my 1275 auto transmission. When selecting d the car starts off in 4th gear. It changes manually through all 4 gears with the selector fine. It also does not kick down and the linkage is in place. It has been working fine prior to this.
It has had fresh oil and filter from minispares. Current mileage around 52k. Any ideas? I have tried adjusting the kickdown lever using the manual but this made no difference. Any Help greatly appreciated. Thanks. Paul

[richard1]

What oil - Specifically - have you been using and are you using?

You said it was from Mini Spares, but I do not see a 10W-40 oil listed on their site, nor an MA2 oil.

If you are using 20W-50, it will not circulate properly through the valves.

Tarija and Santa Cruz, Bolivia

[jockduck]

I used 20/50 mineral oil for years in my auto mini and while things are a bit sluggish when cold it works fine when warmed up.
Jock