Using an auto tranny as a manual

MrBooby

MrBooby

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Jul 20, 2008
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114
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new jersey, usa
How bad is it? My car has that Manual mode(complete crap), but at least it lets me down shift to whatever gear I need, out of the 6. I've been using my auto tranny to do engine breaking. For example, I would downshift (from 6th to 4th at ~40-45mph) if I'm coming down a hill and the person infront of me is riding the brakes.:mad: I do know though that it adds stress onto the engine and gearbox, but I doubt it could be too much.
 
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Which car/auto trans is this? Some don't seem to care, some will grenade after any significant "manual" usage.

That said, brake pads and rotors are invariably a hell of a lot cheaper than a transmission rebuild.
 
Depends on the car I guess - my transmission in my E34 will automatically downshift a couple of gears to keep constant speed down hills at fast speeds. I doubt BMW would program it to do that if it caused a large amount of stress on the ZF box.
 
I've been using my tranny in manual mode for quite a bit and it doesn't do anything to it. Really shifting yourself doesn't really do anything to the tranny that shifting automatically wouldn't. Only difference in my case would be the fact that in manual mode it locks the TC faster. I would avoid downshifting from 6th to 4th to engine brake on a hill though. Brakes are cheaper after all and made for that task :)
 
I've heard bad things about engine braking. But if your Lexus doesn't like it - it will prohibit you from doing it. Just like it won't let you rev the nuts out of it. That said; it doesn't make it good.

I think unless your car blips the throttle on down shifts, it might not be good. But I don't know, to tell you the truth....
 
Yeah I noticed the rev limiter thing, it's kind of a good idea though. I remember I hit the gas pedal once in some other car while trying to reach out of the window.
 
prizrak said:
I would avoid downshifting from 6th to 4th to engine brake on a hill though. Brakes are cheaper after all and made for that task :)
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Depends, out here in mountain land we have roads that go down relatively steep grades for miles on end. You can tell the people who aren't from there and the people who are by just waiting at the bottom. The cars with bad burning brake smell aren't from the area. You'll notice the little towns at the bottom of those roads always have a booming brake replacement place or three, because the tourists burn them off on the downhill drive and then can't stop properly because they've got no brakes left. You go into a lower gear with your auto in those situations and you don't need to ride the brake, just be smart and use the proper lower gear. I'll take harmless engine braking over not being able to stop.
 
Nabster said:
Depends, out here in mountain land we have roads that go down relatively steep grades for miles on end. You can tell the people who aren't from there and the people who are by just waiting at the bottom. The cars with bad burning brake smell aren't from the area. You'll notice the little towns at the bottom of those roads always have a booming brake replacement place or three, because the tourists burn them off on the downhill drive and then can't stop properly because they've got no brakes left. You go into a lower gear with your auto in those situations and you don't need to ride the brake, just be smart and use the proper lower gear. I'll take harmless engine braking over not being able to stop.
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Why not engage the highest gear you have and just ride it out? Free mileage!
 
If the hill is steep enough, you will be going way too fast by the bottom of the hill without some form of braking. Particularly if the road is twisty.
 
Posmo said:
Why not engage the highest gear you have and just ride it out? Free mileage!
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Also if there is a car infront you that tries to stay at the speed limit(40) by riding the brakes, then you'll always be tail gating them by constantly accelarating.

@SL65, it doesn't bleep the throttle, I'm pretty sure that's only possible on high tech dual-clutch trannies and obviously regular manuals with Heel-Toe. But since nobody does Heel-Toe in normal driving, why would it be bad for my car if it's not bad for a regular manual car?

The reason I'm confused is because the car has those craptastic paddle shifters which suggest that you can use the tranny in Sport mode. And the downshifts don't feel that bad.
 
MrBooby said:
@SL65, it doesn't bleep the throttle, I'm pretty sure that's only possible on high tech dual-clutch trannies and obviously regular manuals with Heel-Toe.
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If I'm not mistaken, automatics can be programmed to do it. HSVs (Tuned Commodores/Pontiac G8s) blip the throttle when you downshift in the manual override mode. They've got GM 6L60E 6 Speed Autos.
 
Posmo said:
Why not engage the highest gear you have and just ride it out? Free mileage!
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Downhill roads in wyoming often look like this

Beartooth_Highway.jpg


If you can coast down that with no brakes, you are a braver man than I*





*I've driven that road and at some points it is bloody terrifying.
 
well, i drive my auto as a manual, but i do blip the throttle on downshifts when i am slowing down for a corner (otherwise i just let it sit in drive, and drop it to 1st when i stop)

but, my transmission is an old ford "Select-Shift" 3 speed C4, so the shifts are slow enough that i *can* heel toe it lol :p
Its just a bit of a pain to do with the rather poorly positioned pedals..
 
prizrak said:
Really shifting yourself doesn't really do anything to the tranny that shifting automatically wouldn't.
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I agree. There is no reason why it would do something bad to your engine/transmission.
As long as you don't go from 6th to 2nd at 80mph!

And downshifting from 6th to 4th shouldn't be a problem either, I don't think it will even hit the limiter if you are not going faster than 70mph.
 
AFAIK it doesn't hurt the gearbox. Anything completely idiotic (like downshifting from 3rd to 2nd gear @ 90 kph, which is what I did in my old, manual Golf) is impossible because the auto box goes "computer says NO"
 
Crazyjeeper said:
Downhill roads in wyoming often look like this

Beartooth_Highway.jpg


If you can coast down that with no brakes, you are a braver man than I*





*I've driven that road and at some points it is bloody terrifying.
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Ha. Yeah that road is a bit silly. We have one about 30 miles west of town here that runs up the mountains so high you actually pass the tree line- elevation so high trees don't grow there.

On an unrelated note, I just remembered something in my Mustang's owners manual. It says you can shift into first gear at speeds up to 70 mph, and that's the 3 speed auto :blink:
 
Nabster said:
On an unrelated note, I just remembered something in my Mustang's owners manual. It says you can shift into first gear at speeds up to 70 mph, and that's the 3 speed auto :blink:
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70 in first? damn lol,,, I most likely have the same trans as you but I doubt I could do more then 40, 45 in first lol... hell, by 70 I am running out of gear in second
Thinking about it, even if I drop it down to first (at say, 60 mph) it wont actually shift into first until around 25 mph, unless I blip the throttle perfectly. (Been there, Done that ;))


but yeah, i don't think it would hurt anything either, unless the trans is an early GM 4 speed overdrive (700r4) which are known to be rather weak... and if it does break something, then you just gave yourself a perfect reason to go out and buy a manual car :lol:
 
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That would be limited to the earliest TH700R4s, where the input shaft would snap. That was fixed by 86, IIRC.

That said, it's a bad idea to manually downshift on a regular basis on most older automatics. Computer controlled ones are usually okay with it.

On the other hand, it still puts wear on the bands, and brakes are cheaper to service than transmission overhauls are.
 
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