Noob questions re using automatic transmission

[90GXL Lurker Find all posts View Profile Close 90GXL]

Hi all,

I’ve only ever driven manual-transmission cars and recently picked up a 2001 90 series with automatic transmission - as such (despite being reasonably mechanically-minded) I have a couple of complete noob questions re using the automatic transmission:

When stationary, with the engine idling and the transmission selector lever in D / 2 / L or R, where is the clutch between the spinning and stationary parts of the drivetrain? Is this within the trans? or between the engine / trans or trans / wheels?

Next, when moving the transmission-selector from Reverse into a forward drive position (D, 2, L) - is there any merit to pausing momentarily in the ‘N’ detent? Just thinking along the lines of allowing any spinning parts to slow/stop before sending them into the other direction? I’ve noticed the transmission-selector can easily just ‘skip’ through the N position when moving it from R towards D.

Cheers - sorry if the questions are a bit basic!

[carco Advanced Member Find all posts View Profile Close carco]

Instead of a friction dry plate clutch bolted to the flywheel as in a manual, an auto has a fluid coupling called the torque convertor.
The actual flywheel is also a flimsy arrangement renamed as the flex plate and simply carries the starter ring gear and the heavy torque convertor.
The fluid coupling is designed to slip until certain rpm is achieved. So in answer to your question, it's the torque convertor that is the link between the stationary and spinning components.
However the transmission also has multi plate wet clutches which will slip until oil pressure increases with engine rpm.
The convertor also has an inbuilt wet clutch that "locks up" at highway cruising speed, thus there's no further convertor. The lock up clutch improves fuel economy and reduces transmission oil heat buildup.
The slipping action between input and output of the torque convertor heats the oil a lot, so your transmission recirculates transmission oil through a heat exchanger mounted inside the bottom tank of your radiator.
Working the vehicle hard in soft sand etc with the convertor slipping constantly can boil the transmission oil so it's advisable to select low range to reduce the load on the transmission.
Fitting an aftermarket transmission oil cooler will also help cool that oil.
Your car has a dash mounted transmission over temp warning light.

[carco Advanced Member Find all posts View Profile Close carco]

When moving the gear selector from D to R etc, you're only actually opening /closing electrical contacts, nothing mechanical. (except P)
I think it's good practice to stop the car before changing gears but you'll find the auto is so forgiving that pretty soon you'll be as lazy as the rest of us and grab R while she's still rolling ahead.
The drive line is quite heavy, has a lot of inertia and will clunk (D to R)
The auto was a well built model and will give excellent service when driven as a car only. Towing will reduce its life considerably especially since it's already 15 years old.
Heat is the enemy with an auto and your oil condition (colour, smell) will tell you everything you need to know.