97 CR-V Lockup Torque Converter Problem

My '97 CR-V tranny won't lock up in 4th gear. I had a mechanic who had heard of the problem, but he left town and no one I've talked to has heard of this.

The remedy is supposed to be replacing the original thermostat with a hotter one. We had done this with a slightly hotter thermostat, but the problem persists. It's worse in cold weather.

Anyone have information?

:banghead:

Have you changed your tranny fluid?

Yes, did a complete tranny service.

It works correctly in warm weather. Only whewn the temp drops below 70 does it have theshifting problem.:banghead:

No Check engine light

Negative.

I readon another Honda forum that the culprit is the thermostat. But what I cannot find is a TSB or anyone who knows what temp thermostat I need to install.