QUESTION FOR CROSLEY

[PeterR]

My daily driver has a 460LE transmission.    It has never caused any problems but from new has displayed something weird.

If the motor is started with the trans in neutral, vehicle on level ground, both foot brake and park brake released; the car moves forward about 3 feet then rolls to a stop.

I normally have my foot on the brake when starting, so can not remember how I first came to notice this, and just out of curiosity I have repeated the exercise a few times over the years always with the same outcome.

It is as if one of the forward clutches is engaged until the pump builds up pressure.

Do you have an explanation Crosley?

[Crosley.In.AZ]

My daily driver has a 460LE transmission.    It has never caused any problems but from new has displayed something weird.

If the motor is started with the trans in neutral, vehicle on level ground, both foot brake and park brake released; the car moves forward about 3 feet then rolls to a stop.

I normally have my foot on the brake when starting, so can not remember how I first came to notice this, and just out of curiosity I have repeated the exercise a few times over the years always with the same outcome.

It is as if one of the forward clutches is engaged until the pump builds up pressure.

Do you have an explanation Crosley?

The clutch packs are "applied " via the oil pressure from the pump.  Not disengaged.

What is happening is common. Some transmissions do this more than others.

it is simply the oil , frictions & steels draging against each other very slightly. The vehicle moves slightly.  If the transmission is in park. You may notice the vehicle will slightly drift forward till the parking mechanism stops the vehicle

When you start the vehicle. The input shaft of the transmission is spinning with the torque converter.  So  , a few internal transmission parts are spining at engine RPM.

You will see this more in colder temps than warm, simply because the oil is slightly thicker.

If the transmission has damaged clutch packs, they can cause  the vehicle to move forward to the point that the brakes need to be applied to stop the vehicle.  The vehicle can feel like it is in gear at all times such as:  neutral , park.

[PeterR]

Thanks for the explanation.

The clutch packs are "applied " via the oil pressure from the pump.  Not disengaged.

That is what I always believed and made this seem so strange.

You will see this more in colder temps than warm, simply because the oil is slightly thicker.

I suspect this has occurred after the vehicle has been parked and everything s cold, as an experiment I will try this after a trip when the transmission oil is warm.

[PeterR]

Well, I tried this at the end of a trip after the trans fluid was up to operating temperature.    The vehicle moved about two inches instead of about 3 feet when cold.