Auto Trans NTK Thread

[kjoons]

I tried searching and couldn't find anything on this, if there is info out there, by all means lock and delete this thread.

NTK = Nice To Know

So, my question is, what to do and what not to do with the automatic transmission? Cruising at 40mph in 7th gear, down shifting while approaching a light or stop sign while the ecu is already down shifting for you, etc etc...

What is more likely to cause more wear and tear? Manual shifting in the mountains or around the city, etc.

I've done a bit of reading on the trans, and from my take, it's a traditional Auto trans, designed and tuned and built to perform as close to or better than a sequential gear box (like the M3s and GTRs). We still use wet clutch packs, planetary gears, automatic trans fluid, etc and yet the trans performs like a sequential gear box! i was actually almost 90% certain that they adopted a smaller and simpler version of the GTRs double clutch seq gear box until I finally read up on it the other day!

Any feed back is appreciated!

[DEpointfive0]

Dafuq did I just read?

[DarkJak]

I heard it's best to downshift as much as possible when I brake and to neutral drop it from every stop light. I also like to cruise on the highway in 3rd gear.

[kjoons]

Originally Posted by DEpointfive0

Dafuq did I just read?

exactly. it was a bit to grasp what Nissan was selling the transmission as, long story short its a traditional auto transmission (like ones in automatic Camry's) tuned and built to perform like a sequential gear box (GTRs and F1 cars utilize these).

not sure if it was confusing or if there was too much tech info, but this type of trans is new to me, and probably new to a lot of people, so i'm trying to figure out what exactly is good and bad for the transmission.

bare with me... i'm very meticulous when it comes to my mechanics, as I've been a mechanic for quite some time and most of my childhood, so i like to diagnose, fix, and understand every vehicle i drive.

[kjoons]

Originally Posted by DarkJak

I heard it's best to downshift as much as possible when I brake and to neutral drop it from every stop light. I also like to cruise on the highway in 3rd gear.

thanks on the feed back... so you smack the down shift as you brake (avoiding over rev obviously)? and neutral dropping meaning, you're in auto and as you come up to the light, you pop it into neutral?

also, i understand that "D" mode is the mode that wont cause any harm to the trans, as it's all ECU at that point.. what i want to know is, what's bad to do in manual mode?

example: the other day i was approaching a stop sign in manual mode, as i braked in 4th gear, the trans already began to down shift for me, being new to the car, i tapped the downshift paddle, only for it jerk and do a double down shift. bad? perhaps not. good? i doubt it. but everything adds up at the 100K mark.

[DarkJak]

Wait, I was totally joking. And no, a neutral drop is when you rev in neutral and drop it into D. Never do this O_O It's awful on your transmission.

If you want your transmission to last long, let it be in the highest gear possible, which is pretty much what it will try to do in D, for efficiency, but it's also the least stressful since the engine will have the least torque and rpm. Also, hard driving will heat up the transmission, and if it's really beaten on, the overheating could reduce life. Same goes for drifting, burnouts, or any sort of wheelspin due to the change in wheel speed when it goes from slip to grip, bringing a shock on the trasmission.
I don't think double downshifting is that harmful if you are only doing it during spirited drives. It'll put more strain on all the parts but the electronics that control our transmissions won't allow it to overrev, which is good. But you shouldn't use the engine braking from downshifting to brake. It's less predictable and causes more stress. Brake pads are MUCH cheaper to replace than a new transmission ($200-300 vs $7000+).

If you really want to help lengthen transmission life and power capacity, a transmission cooler and valve body upgrade would really help it deal with forced induction.

A small tip: to avoid any jerkiness in manual mode, keep your pedal position steady throughout the shift. So if you are cruising, don't mash on the gas halfway through the downshift.

[kjoons]

that was the answer i was looking for.

didn't quite understand your first post, it was a little too vague, but with the explanation i see the sarcasm now lol.

so downshift engine brake is bad and should only be used on spirited drives, meaning "rarely" ? ... i was under the impression the transmission was built for this, considering the wet clutch packs, the synchro rev, and the rest of the beefy drive line. like motorcycles, those driveline/engine combos require you to engine brake.

as long as everything feels smooth during the down shift engine brakes, i dont see a real problem with doing this often. unless, you've got solid evidence that it does? i'd like to see it, i'm still trying to understand how and why this transmission is efficient.