When to turn off Overdrive switch on Tundra?

When should the overdrive switch be turned off with an automatic
transmission Tundra? What's the difference(s)?

On Mon, 30 Jan 2006 05:03:24 GMT, Phisherman <noone@nobody.com> wrote:
[color=blue]
>When should the overdrive switch be turned off with an automatic
>transmission Tundra? What's the difference(s)?[/color]

1. Going down a fairly steep grade where you're tapping the brakes
(or hitting them pretty hard) to drop speed and hold your desired
cruising speed.

This will let the engine take some of the braking load, and keep you
from wearing out your brakes - or worse, overheating the brakes to the
point where the pad material goes into heat-fade and become far less
effective, or past that point to where the brake fluid boils in the
calipers and you get temporary total brake failure.

(This is Not Good.)

2. Going down a fairly steep grade when fully loaded and/or towing a
heavy trailer - See #1.

3. Going up a moderate grade when towing a trailer, or up a steep
grade when moderately loaded, and you notice that the transmission
keeps "hunting" back and forth between 3rd and OD to hold your desired
speed. Better to lock it into 3rd and save the wear on the trans.

And in all these situations, if it's a really steep hill and/or you
are heavily loaded, and the transmission is hunting between 3rd and
2nd, drop it into 2nd manually and don't be in a hurry.

The rule the Heavy Truck drivers use is "Do not go down a hill any
faster than you can go up it." You don't have to be quite as paranoid
about it in a small truck, but being a little more cautious can save a
lot of unneeded wear on the equipment.

--<< Bruce >>--

--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
5737 Kanan Rd. #359, Agoura CA 91301 (818) 889-9545
Spamtrapped address: Remove the python and the invalid, and use a net.

Good advice.
A point can also be made to turn off the OD whenever you are towing a
heavy load. OD gears up the transmission and tends to put more stress on
parts. Without OD, the engine will turn faster, but the transmission will
be in 1:1 (depending on the tranny) gear. The strongest gear you got.

If you need the engine to slow you down and stop the brakes from burning
out, then you are going too fast with too heavy a load. Slow down.
Brakes are dirt cheap next to a transmission rebuild.


On Sun, 29 Jan 2006 22:07:56 -0800, Bruce L. Bergman wrote:
[color=blue]
> On Mon, 30 Jan 2006 05:03:24 GMT, Phisherman <noone@nobody.com> wrote:
>[color=green]
>>When should the overdrive switch be turned off with an automatic
>>transmission Tundra? What's the difference(s)?[/color]
>
> 1. Going down a fairly steep grade where you're tapping the brakes (or
> hitting them pretty hard) to drop speed and hold your desired cruising
> speed.
>
> This will let the engine take some of the braking load, and keep you
> from wearing out your brakes - or worse, overheating the brakes to the
> point where the pad material goes into heat-fade and become far less
> effective, or past that point to where the brake fluid boils in the
> calipers and you get temporary total brake failure.
>
> (This is Not Good.)
>
> 2. Going down a fairly steep grade when fully loaded and/or towing a
> heavy trailer - See #1.
>
> 3. Going up a moderate grade when towing a trailer, or up a steep grade
> when moderately loaded, and you notice that the transmission keeps
> "hunting" back and forth between 3rd and OD to hold your desired speed.
> Better to lock it into 3rd and save the wear on the trans.
>
> And in all these situations, if it's a really steep hill and/or you
> are heavily loaded, and the transmission is hunting between 3rd and 2nd,
> drop it into 2nd manually and don't be in a hurry.
>
> The rule the Heavy Truck drivers use is "Do not go down a hill any
> faster than you can go up it." You don't have to be quite as paranoid
> about it in a small truck, but being a little more cautious can save a
> lot of unneeded wear on the equipment.
>
> --<< Bruce >>--[/color]

On Sun, 29 Jan 2006 23:17:31 -0800, Eddie <no@spamatall.com> wrote:
[color=blue]
>If you need the engine to slow you down and stop the brakes from burning
>out, then you are going too fast with too heavy a load. Slow down.
>Brakes are dirt cheap next to a transmission rebuild.[/color]

Yes, but it's not just a question of money and what is cheaper to
repair. If the transmission fails under those conditions, you pull
over and stop. Annoying, expensive, but not normally hazardous to
life and property.

If the brakes overheat and fail you DON'T STOP - and that can get
you killed, or seriously mess up your vehicle...

Given those two choices, I'll drop a gear (or two) and ease down the
hill without overloading the brakes every single time. Save the
brakes for when traffic comes to an abrupt stop at the bottom of the
hill.

Welcome to the North I-405 approaching the US-101 interchange at any
time of the day - a 3-mile 8% downgrade with a perpetual traffic jam
at the bottom. Being able to stop when you need to is a good thing.

Been There, Done That, Have the T-Shirt.

--<< Bruce >>--

--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
5737 Kanan Rd. #359, Agoura CA 91301 (818) 889-9545
Spamtrapped address: Remove the python and the invalid, and use a net.

On Mon, 30 Jan 2006 05:03:24 GMT, Phisherman <noone@nobody.com> found these
unused words floating about:
[color=blue]
>When should the overdrive switch be turned off with an automatic
>transmission Tundra? What's the difference(s)?[/color]

If you RTFM, it will tell you.

Overdrive = no engine braking and lower torque.

If you're pulling not only switch off the OD, but switch ON the "Power
Boost" (IF the Tundra has one - Tacoma does).

On Mon, 30 Jan 2006 09:27:28 -0800, J. A. Mc. <jaSPAMc@gbr.online.com>
wrote:
[color=blue]
>On Mon, 30 Jan 2006 05:03:24 GMT, Phisherman <noone@nobody.com> found these
>unused words floating about:
>[color=green]
>>When should the overdrive switch be turned off with an automatic
>>transmission Tundra? What's the difference(s)?[/color]
>
>If you RTFM, it will tell you.
>
>Overdrive = no engine braking and lower torque.
>
>If you're pulling not only switch off the OD, but switch ON the "Power
>Boost" (IF the Tundra has one - Tacoma does).[/color]


I read the manual, then posted here. The 2006 Owner's Manual says
nothing about when to turn the Overdrive off, just how to do it. By
default the Overdrive is ON.

To make matters a bit more confusing, there is a "Shift L" switch on
the dash. The manual says to turn this Shift L switch on to enable
maximum braking--does this mean the Overdrive switch should be off
when the Shift L is on? Further, it says not to use the Shift L
switch for "a long time" when climbing a hill or hard towing, else it
could result in severe transmission damage or overheating. So what's
"a long time?"

While climbing very long hills, and the transmission constantly shifts out
of OD -- downshifts -- and back again -- upshifts -- it is a good idea to
use the button to defeat the OD functiion. Let the truck climb the hill in
3rd of 4rt, whichever the highest gear is that you have, but is not
overdrive.

The same rule of thumb applies to ANY overdrive transmission, not just the
Tundra.




"Phisherman" <noone@nobody.com> wrote in message
news:d77rt1lgfc0rjfgqihv24a2breq9vrqkua@4ax.com...[color=blue]
> When should the overdrive switch be turned off with an automatic
> transmission Tundra? What's the difference(s)?[/color]

Phisherman wrote:[color=blue]
> When should the overdrive switch be turned off with an automatic
> transmission Tundra? What's the difference(s)?[/color]
2000-2002 Tundras have a weak overdrive section in the transmission.
Always switch out of overdrive when towing or when hauling a heavy
load. The other advice given is also very good, except the part
about not using the transmission to slow the truck on long
downgrades. If your brakes overheat and fail, you crash. The
brakes are best for short downgrades, and the transmission best for
long downgrades. On a long downgrade, downshift to the gear that
keeps you near the speed you feel is safe. When you gain to your
max safe speed, brake moderately hard to slow below that safe speed,
then get off the brakes and let them cool. When you're back up to
your max safe speed, brake again, etc., etc.


Ken