What is this switch under the radio for?

Crazy question guys, but I figured someone could answer this far me. Looking at a gen 1 tundra for my son. What is the switch under the radio, that says shift L?

 

Never had a gen 1 or sat in a gen 1 4x4, so just curious. The 4wd selector switch is located a little lower than this switch in pic.

 

ok, odd yes, but thanks for the reply. Good to know.

 

For the love of God, don't push it to figure out what it does while doing 40km/h like I did. I thought I was gonna tear the transmission out!! LOL.

 

Yeah, it was not one of my better moments. I have a thing for just experimenting, especially with mystery buttons. I noticed it on the 2nd or 3rd day I had my truck and it went basically like this:

"I wonder what that does..."

*push*

"fuck fuck fuck fuck!!!!"

*frantically un-push button, pull over the road side, check vitals to ensure the heart attack was of only minor seriousness, then assess truck for damage*

Got away with that stunt once. Not gonna tempt fate again. LOL

 

Looks like 4L

 

You need to be in second gear to activate the shift L button.

 

Only the later 1st gen Tundra's have this button, up to 2004 they used a 4spd auto transmission, then switched to the 5spd auto in 2005 IIRC. They added this switch to avoid redesigning the whole column shifter to accomodate the 5spd, at least that is my theory, and I'm sticking to it.

 

This button locks it in 1st gear. It's primary function is for steep descents on the trail. When climbing it'll downshift to first no problem. If you don't activate it you'll be riding the brakes downhill. Scary moment, when I was descending a steep, loose trail without the L button engaged, the ABS kicked in, its supposed to be disabled in 4wd, and my son and I went careening down the mountain. Luckily I was able to get er slowed enough to hit the button. Lesson learned!