So, here in Southern California we have a long, steep hill (the 101Fwy into Camarillo, CA). Would putting it into 3 or 2 damage the transmission when going down a really long and steep hill?

 

Putting the transmission in manual mode to hold your speed on a long downhill run will not hurt it at all, though I doubt you'll need to use 3rd or 2nd gears. In fact it's a good idea, it saves your brakes for when you really need them, and reduces brake wear.
Regards,

 

+1, I use the manual gate all the time going from my house down Haleakala Hwy on Maui. 8 miles long and 2000' to sea level. Often use the manual gate to slow down for traffic lights, as noted this really saves the brakes!

 

I know that hill well!! Whenever going down the hill in any car I have owned I always downshifted my automatic trans cars into a lower gear--doesn't hurt and saves the brakes.

The most harrowing experience I had with this hill was many years ago going up the hill in a rented Ford Pinto that had a failing fuel pump. It was like a bad (dangerous) comedy trying to coax the car to the crest.

Doug

 

+1: saves brakes and *fuel*

 

The flip side of the argument is that, when in doubt, it is better to put wear on a $50 set of brake pads than putting heat and wear into a $5,000 transmission. Obviously, this argument holds only up to the point where the brake fluid boils or the pads glaze from heat...

 

Nothing more to say.

 

Imagine trying to go up that hill in a 1974 Triumph Spitfire! Did that for over a year.

 

Not only will it not do any damage, it is even recommended in the Driver's Handbook:


(click on the image to enlarge it)

Graham