'01 OBW Automatic Transmission lockup

How can you tell?

It will not lock-up until a reselected transmission tempter is reached. I protect the engine from lugging when cold. eddie. My 2000 Forester takes ~

ED, what would be bad about lugging an engine when cold? Is it an oil circulation thing? Generally, an engine will heat up more if lugged due to longer duration of exhast gasses in cylinder/head area.

tia

Carl

Edward Hayes wrote:

The lock-up doesn't work until the oil temperature reaches about 18-20C. I guess it is to protect the transmission, by warming the oil up to its working temperature as soon as possible; the torque converter slip will heat the oil.

I can tell by 1) watching the tachometer and 2)listening to and feeling the engine change pitch.

Mike

Carl 1; Lugging an engine is asking for high loads at very low rpms which raises combustion pressures very high which is tough on slow turning bearings. Hydrodynamic lubrication requires some minimum shaft speed to achieve best lubrication. In addition; cylinder walls & pistons are lubricated by oil thrown from the spring crankshaft and cold oil is thick. Porsche did an extensive study years ago and determined that oil has a preferred running temperature( where it lubricates) the best and it was quite high as I remember, something like 170 degrees F.

I think it protects the torque converter clutch from slippage when the fluid is too thick to allow it to lock up properly.

Maybe it serves a dual purpose R???? eddie