Overdrive off for engine braking

[domstriker]

I mentioned in a previous thread how my 01 is the first automatic transmission I've ever owned. I'm not used to constantly applying the brake to maintain speed when following someone or when just cruising around town.

I noticed that if I disengage the overdrive, engine rpms will go up and slow down the vehicle a little bit. Is this bad for my 4R?

 

[brian2sun]

No, it's not bad at all. O/D is just your high gear (like 5th in a manual) so all it does it make the tranny downshift into it's next lower gear (3rd in an auto). The autos are 4 speeds so... "L" locks it in 1st gear, "2" makes it so the tranny will only use 1st and 2nd gear, "D" makes the tranny use 1st, 2nd, and 3rd gear, and O/D uses all 4 gears.

 

[theizzardking]

personally i think that's a stupid idea, way to burn up clutch packs and heat up your tq converter instead of just taking your foot off the gas a few seconds earlier and feathering the gas pedal , the best thing you can do for the longevity of your truck is to change your driving style.

this is an automatic and actively trying to engine brake on the freeway is a bad idea, the only time you should actively be trying to engine brake is on the trail and then you just lock it in 1st or second, beyond that you just drive normally and feel where the truck is and give gas accordingly.

sorry but using the o/d off feature to drop a gear for engine braking is stupid imo and your going to burn through your trans far quicker then a person who drives normally.....

 

[theizzardking]

i should say though that you can just drive with it off all the time if you want more compression for engine braking, it's just re****ed to try and use teh o/d button as a cheesy shifter of sorts, every time you hit the o/d button to drop the rpm's it heats up the torque converter quite a bit and wears on teh clutch packs harder then normal, so choose a mode for the most part and stick with it and only use the o/d button when you need it.

 

[brian2sun]

personally i think that's a stupid idea, way to burn up clutch packs and heat up your tq converter instead of just taking your foot off the gas a few seconds earlier and feathering the gas pedal , the best thing you can do for the longevity of your truck is to change your driving style.

this is an automatic and actively trying to engine brake on the freeway is a bad idea, the only time you should actively be trying to engine brake is on the trail and then you just lock it in 1st or second, beyond that you just drive normally and feel where the truck is and give gas accordingly.

sorry but using the o/d off feature to drop a gear for engine braking is stupid imo and your going to burn through your trans far quicker then a person who drives normally.....

It really depends on the road you are driving. I descend a 20 mile, 6,000 ft. mountain road in which the average speed is ~60 mph and I have to do it 3 or 4 times a week. 2nd is way too low, and with O/D on it's too high. I would go through brake pads about 3 times faster if I don't lock it in 1st-3rd (with O/D off). To use it for engine braking on the freeway is kind of a wierd thing to do, but to descend a long hill, it works wondrfully, keeps your speed reasonable, and the torque converter isn't being used during that time, it's just in 3rd gear.

 

[theizzardking]

It really depends on the road you are driving. I descend a 20 mile, 6,000 ft. mountain road in which the average speed is ~60 mph and I have to do it 3 or 4 times a week. 2nd is way too low, and with O/D on it's too high. I would go through brake pads about 3 times faster if I don't lock it in 1st-3rd (with O/D off). To use it for engine braking on the freeway is kind of a wierd thing to do, but to descend a long hill, it works wondrfully, keeps your speed reasonable, and the torque converter isn't being used during that time, it's just in 3rd gear.

it's not wired ,it's stupid......

your point is becuase of where you live you drive with it off most of the time, and made reference to that in the post above you, you can just leave it off or on which ever you prefer for your area, you can't be cruising on a flat road doing 60 come up behind someone and hit the o/d button instead of your breaks to slow you down that will break shit far far quicker then normal wear, that's what the op's intentions are.... like a stick, sorry but that's really stupid, you use the o/d button sparingly as you actually need it, as described above, also meaning you use it to either engine brake on the way down from a mountain on a 60 mph road or you use it to go up a mountian at 60 mph ....you know use it as it was designed for not becuase you hate tapping your breaks or letting up off the gas before you come up on someone in normal driving conditions.

and really think about it which would you rather burn through 3 times as fast pads or transmissions?

 

[brian2sun]

Ok, I see now. I totally agree, the concept of using it randomly to slow down on the freeway is not a good idea. I didn't realize this is what he was actually talking about. I guess it's because the idea is so foreign to me. I just turn it off and leave it off for the entire way down and up. Once I'm on the freeway I leave it on and around town I leave it off. I would definitely not use it in the way that you're saying is dumb.

To use it on long decents/ascents is a good thing though and that won't cause any harm to your tranny.

 

[theizzardking]

yeah it sounds like he has only driven manuals before or something, nothing wrong with doing that at all i would always down shift before hitting the brakes with a manual, it's just that concept doesn't fly with with an auto, it's like people who have only driven auto's don't usually know wtf engine braking is until you explain it to them, bottom line is they are different systems and you need to drive each as they were meant.


but then again i could be wrong brain, i just don;t get what teh op is asking, either way it doesn't make any sense to me, as if he was asking what you answered , then what's the point of the o/d in the first place?
and if he was asking the way i answered you'll brake something doing that,
i guess we need him to post up again to see what he was really after, cause really we're both right just arguing different points on the same side, lol

 

[brian2sun]

but then again i could be wrong brain, i just don;t get what teh op is asking, either way it doesn't make any sense to me, as if he was asking what you answered , then what's the point of the o/d in the first place?
and if he was asking the way i answered you'll brake something doing that,
i guess we need him to post up again to see what he was really after, cause really we're both right just arguing different points on the same side, lol

haha, for sure. OP needs to explain more what he's trying to do.

 

[JohnsD90]

Win for the Manual transmission, 5 gears Bltchs! No burning up torque converters.

 

[004Gunner]

Win for the Manual transmission, 5 gears Bltchs! No burning up torque converters.

I saw your name as the last reply from the main page and knew I would be reading a "f*** autos" type comment

I use the O/D off for engine braking on long hills like Brian described. I don't want my brakes cooked out if I need to make an emergency stop so that's why I engine brake. Hopefully it doesn't fry my transmission prematurely and hopefully my external cooler helps.

 

[brian2sun]

I've logged about 400K between 3 different auto 4runners and have always done this so I can say for sure, there is no harm in doing this 004Gunner. This is the main reason why Toyota made O/D selectable - not so much so you can turn it on, but so that you can turn it off and keep it in 3rd. It's just a way to isolate 1st-3rd.

For clarification, my practice of leaving O/D off when going down/up the mountain doesn't use the torque converter at all so it definitely doesn't cause it to wear faster. However toggling O/D on and off is basically shifting between 3rd and 4th which does use the torque converter while making those shifts and will cause premature wear.

If I leave O/D on when it really should be off (like when going up the mountain), I will put much more wear on my tranny. I have done this to see what happens before and in my 20 mile mountain drive...
-If I leave the O/D on: it will shift 25-30 times between 3rd and 4th during those 20 miles and sometimes the torque converter will lock up for minutes at a time which generates excessive heat and causes premature damage over time.
-If I turn O/D off: it will not shift at all during those 20 miles (just stays in 3rd the whole time) and the torque converter doesn't get used at all. And I have a lot more power too.

I can tell by the "heat of the hump" alone that leaving O/D off in these kinds of circumstances creates much less heat and is much easier on the tranny/TC.

 

[JohnsD90]

They could have just made the Shifter go, PRND321, like a normal car. SO what i am gathering here is that there is no overdrive, it is 4th gear, not overdrive.

 

[brian2sun]

They could have just made the Shifter go, PRND321, like a normal car. SO what i am gathering here is that there is no overdrive, it is 4th gear, not overdrive.

O/D allows the 4th gear to be used, but it also allows for the TC to lock up in between 3rd and 4th. If O/D is off, you only get 1st-3rd gears. With O/D on, you still get 1st-3rd (obviously) but you get 4th and the TC (or passing gear) between 3rd and 4th. If you're in O/D (4th) and give it about 1/2 throttle, instead of dropping to 3rd, it will lock up the TC and your rpms will be about 300-350 higher than just 3rd (which gives you that little edge for more power).

 

[brian2sun]

That locking up of the TC all the time (in reference to the OP's question and part of what izzard was saying) is what really generates heat and kills the tranny if it's used too much by pressing the button. Anytime you press the button, at least for a short time the TC is used during the shifting process. And that's like everything I know about trannies so I'll shut up now. :tongue: Oh, yeah and they look like the death star when you take the pan off. :vader:

 

[theizzardking]

haha that's exactly what i was trying to say all along Brian! good clarification man, much more articulate then the way i was tying to explain it, lol :driving: