Lazy trans after warm up

[hawaiianmini]

Aloha,

One of our JDM automatic Minis has a problem once warmed up after 15 minutes or a few miles. Cold it shifts fine, but after awhile, it starts to flare, and if shut down and restarted hot it has trouble getting into gear. An oil change to an MA2 oil made a difference. But not a cure once driven for a while the problems come back.

Am I looking at a rebuild?

[jockduck]

Hi again, its been said on this list before, the first thing I would do is a transmission oil pressure test/stall test, its in any decent manual. It sounds like you have a drop of oil pressure once the engine is warm, or perhaps the friction surfaces of the clutches have been contaminated with friction modifiers from a previous oil fill.
Jock

[richard1]

It sounds to me like sticking valves in the valve body. more time with the new oil might fix it, but you might also try another oil change, since 31% of the old oil remains in the engine/trans assembly. It would also help with what jockduck says, as the old oil will have left friction modifiers behind. But I would try to get 500 miles or so on the current oil before changing.

For those that dispute the 31%, check your manual. You will see that:
Mini oil capacity: (same for all engines)
Dry: 16 pints
Wet: 11 pints
5 pints old = 31.25% of total




Tarija and Santa Cruz, Bolivia