Using Overdrive to downshift (automatic)
09-09-2007, 08:31 AM
#1
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Using Overdrive to downshift (automatic)
Hey everyone i was just wondering if there is anything i can damage by repeatedly downshifting with the overdrive button on the stick (automatic transmission). I use it to come to stops from high speeds etc. to save my brakes some wear. Sorry if the question sounds stupid... thanks 
09-09-2007, 08:48 AM
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While it might not cause any overt damage, it *does* generate significantly more heat and heat is the arch enemy of automatic transmissions.
Folks with two views are going to chime in on this, as they always have. Those who downshift their automatics and have had no problems, and those who believe it to be harmful.
The "expired ˟˟˟˟˟-cat" has it right, why build up the heat/risk it when brakes are cheap!
Folks with two views are going to chime in on this, as they always have. Those who downshift their automatics and have had no problems, and those who believe it to be harmful.
The "expired ˟˟˟˟˟-cat" has it right, why build up the heat/risk it when brakes are cheap!
09-09-2007, 08:48 AM
#4
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I agree with cougar -
The gearing in 3rd gear is 1 to 1 - the gearing in OD is less that 1 - 1 - so technically speaking, you should be able to downshift from OD to third with no problem, but why?
The gearing in 3rd gear is 1 to 1 - the gearing in OD is less that 1 - 1 - so technically speaking, you should be able to downshift from OD to third with no problem, but why?
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09-09-2007, 09:43 AM
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the only time i use that feature is when i really need to pass someone. other than that, if you put your foot down it will do the same thing. i see no reason to frequently use that OD button.
09-09-2007, 06:52 PM
#11
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i totally agree with the tranny being worth way more than the brakes so i guess that is good enough a reason for me to stop doing it. Especially since blowing up the tranny would not go to well with my budget.
PS: I wish i had a 5spd
PS: I wish i had a 5spd
09-09-2007, 06:57 PM
#12
eightnine, I don't think downshifting to 3rd to get a little engine break will hurt anything. Surely Toyota wouldn't put a button on their AT's that says "push me to wear out your transmission!"
Your tranny shifts a hundred times every time you drive it around. If you pull off OD from time to time to slow down when going downhill or if you need to stop quickly, then that's only another few times that it shifts.
Your tranny shifts a hundred times every time you drive it around. If you pull off OD from time to time to slow down when going downhill or if you need to stop quickly, then that's only another few times that it shifts.
09-09-2007, 07:00 PM
#13
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Rust Bucket you couldnt be more wrong. Granted I had a Camry but this still applies:
On my old Camry (93 V6) I used to do exactly what the OP is doing, the shifting solenoid (I believe blew) and I couldnt accelerate wortha crap unless I babied it when it was ready to go into gear. I couldnt accelerate off the line, it would go straight to redline and not shift till I let off.
Before it started happening I put about 20k on it using the OD button all the time.
On my old Camry (93 V6) I used to do exactly what the OP is doing, the shifting solenoid (I believe blew) and I couldnt accelerate wortha crap unless I babied it when it was ready to go into gear. I couldnt accelerate off the line, it would go straight to redline and not shift till I let off.
Before it started happening I put about 20k on it using the OD button all the time.
09-09-2007, 07:05 PM
#15
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09-09-2007, 07:49 PM
#16
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Look the shifter in the vehicle. Not that you don't have to start off or stay in 'D'.
What's the big deal with downshifting ? Brakes are there to stop and/or slow the vehicle. They're your friend...
As everyone else has said, brakes are cheap. They're a consumable item. They are meant and designed to wear and be replaced.
Fred
09-09-2007, 07:58 PM
#17
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Dont' sweat it. The torque required to spin a coasting engine is nothing compared to that which is required to accelerate the truck. Every sticks shift does this all the time.
What kills trannies typically is heavy torque loads for long periods of time. For example, when towing, it is FAR easier on the tranny to let the engine rev but at say half throttle than nearly full throttle at a lower RPM.
In our trucks, switching out of OD to downshift has the added benefit that the torque converter locks up which shears the fluid far less and keeps transmission temperatures down. You can save fuel as well as wear and tear by manually shifting to 3rd and climbing a hill with much less pedal than you would if you floor it to kick it down where the torque converter will remain unlocked (in OD setting but in 3rd)
I do not shift to 3rd to hold down speed unless descending a long and steep grade where you can get the brakes quite hot. In that case it is a good idea to use the engine because you can keep the brakes relatively cool in case you really do have to stop quickly. That is not often though.
Frank
What kills trannies typically is heavy torque loads for long periods of time. For example, when towing, it is FAR easier on the tranny to let the engine rev but at say half throttle than nearly full throttle at a lower RPM.
In our trucks, switching out of OD to downshift has the added benefit that the torque converter locks up which shears the fluid far less and keeps transmission temperatures down. You can save fuel as well as wear and tear by manually shifting to 3rd and climbing a hill with much less pedal than you would if you floor it to kick it down where the torque converter will remain unlocked (in OD setting but in 3rd)
I do not shift to 3rd to hold down speed unless descending a long and steep grade where you can get the brakes quite hot. In that case it is a good idea to use the engine because you can keep the brakes relatively cool in case you really do have to stop quickly. That is not often though.
Frank
09-09-2007, 09:04 PM
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i dont know how bad it is...
all i can say is im almost at 200,000 and i have used it most times to stop
i live in cali, and stopping asap can be a must, sometimes on the freeway/ 50mph road. i use my "emergency combo", shift auto down to 2nd o/d off and brake when i have to!
i dont know how bad it could be, ive NEVER replaced the tranny or had to.
one time (well many times)
i have a hard time stopping downhill especially, and it sucks, my buddies runner does a LOT better than mine. and had to swerve to the shoulder lol.
im a good driver though dont get me wrong ive never had a ticket/accident.
all i can say is im almost at 200,000 and i have used it most times to stop
i live in cali, and stopping asap can be a must, sometimes on the freeway/ 50mph road. i use my "emergency combo", shift auto down to 2nd o/d off and brake when i have to!
i dont know how bad it could be, ive NEVER replaced the tranny or had to.
one time (well many times)
i have a hard time stopping downhill especially, and it sucks, my buddies runner does a LOT better than mine. and had to swerve to the shoulder lol.
im a good driver though dont get me wrong ive never had a ticket/accident.
09-10-2007, 08:51 AM
#20
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This is not true, I have a tranny temp gauge and if you are in overdrive traveling down the road and you step on it and it shifts out on its own, your temp will shoot up. Now the same situation, you hit the OD off button, your temp will pretty much stay the same if not drop a bit. Elripster explained the reason very well.
