700R4 torque converter questions.....

[davepl]

Originally Posted by Smokintire70

What is a lockup? Does it lock the engine and transmission at a certain rpm?

Yep. Strategy varies by model, but in most cases they won't lock up unless the transmission is in D and you're at a certain output speed. And there's usually integration with the brake switch so that it unlocks whenever you touch the brakes.

Ideally you'd never feel or know it's doing it, but it helps for mileage as there's then no slip, as opposed to just a little.