Automatic Transmissions Ultimate Guide

[Alfador]

This thread is old as ***.... not too old, but old enough.

Second. Sure, AT is better in a straight line, accelerating. Then again you could train a monkey to shift a manual in a 1/4. I'll take my MT any day thanks. If I wanted a guide on how to make my car drive better in a straight line I'd join a mustang forum. No, I like to turn, and downshift into turns and all. Rev control is a nice thing to have.

[moyea]

Mild Build Budget:<<Option 1>> Valve Body Upgrade Items: RE4R01A Valve Body Time: 3 days (save on downtime by pulling a VB from the yard but adds to cost) Cost: $300-$500

Explanation by Gregg Evans and Lexus IS Forum http://www.chickenears.com/accumulator.htm

Shift Kit A shift kit is the most basic upgrade to a transmission. It usually involves the replacing of a few springs, adding a few spacers, which can range from small puck, small shafts, and washers. Drilling or enlarging a few holes in a separator plate. Adding changing or removing check balls.

* Separator Plate is the pcs that separates the main body and valves of the Valve body from the transmission case this is usually covered on both sides with a gasket with holes for proper fluid flow.

* Check balls are small ball bearings that are used to restrict flow threw a passage in the valve body so that excessive overlap does not occur or that a certain gear is not applied while in the middle of a gear.

Valve body upgrade

A Valve body upgrade is one step up from a shift kit it requires more skill and time to preform. It involves all of the basic items from in shift kit but will also include the following. Full replacement of necessary valves with new valves made to spec these usually replace the valves that were spaced. Involves increasing passage way’s and restricting flow threw certain passages of the Valve body and case. New redesigned gaskets for the separator plate and case.

***Not all of these items are necessary for a valve body upgrade but notice the differences between the shift kit and Valve body upgrade.***

IPT Performance Transmissions has a VB upgrade for our trannys http://www.importperformancetr...shtml

Blah, blah: What's it do?

Firmer shifts, increased cooling, durability, and all around performance can be expected from a VB upgrade. The nice thing about the VB is it will most likely outlast your transmission and can be moved from car to car(4R01A to 4R01A).

Mild Budget Build:<<Option 2>> Torque Converter Upgrade Item: RE4R01A TC or buy a custom TC Time: 4hrs-3days Cost: $400-$1050 (damn!)



I'm not going to get into the explanation of the TC because it was covered many times in the guide. You have two choices: Send your old one in for modification or have a super strong, smaller billet one custom built. The first one will save you money and give you great performance. The billet will reduce rotational mass, be indestructible, and give you superior performance. It will also cost you a small fortune. TC upgrade is the single most popular (and only) upgrade most A/Ters get because it tends to produce the best results. Before running out and get r' done, you should be able to answer these questions: What is my engine output (HP/Tq, etc.)? What is my transmission input and output? How it's all getting to the wheels (weight, final drive, etc.)? What I want from my TC? Here is an example: http://www.tcsperformance.com/ppdnew/techcard.html

If you find a shop, like IPT, that works on Nissan TCs, they can answer most of the questions for you. If your car is mostly stock this is even easier.

Remember this guide is to discuss Nissan A/T's upgrades and not your difference in opinion. Always read the entire post before posting your comments.

Stay tuned for option 3 (TCU) and high end budget.

[HashiriyaS14]

I might need to swap out my A/T altogether. Right now it's just sorta got rough 1-2 shifts, fluid looks clear (time to change), but I'm not very confident in it.

It's surprisingly hard to find a FAQ or writeup on swapping an auto for an auto, lol. Everyone seems to just go to 5MT.

[MinisterofDOOM]

Awesome thread!

You should rehost all these pictures on NICO's Photopost so this thread can remain useful after imageshaq decides to break them.

[moyea]

Not that I want to get into that area of discussion but swapping A/Ts is simple enough. Check your FSM. In the automatic section is detailed instructions on how to do it. I've practiced doing it at least a dozen times at my local junk yard. I suggest you practice there before you do it for real or take it to a shop. Most transmission shops will install it for around $300.

Go ahead and change your fluid, which should look pink/red. Smell the fluid (if it smells burnt thats bad) and check for any metal shavings in the pan.

Good idea Doom, I'm on it.

[koukidough]

Autos may be good on straights but on track its a different story. Manual for da win

[moyea]

Mild Build Budget:<<Option 3>> Aftermarket Transmission Control UnitItems: A standalone aftermarket TCUTime: 1hr to install, 1 day to tuneCost: $700-$900



Paraphrased from Powertrain Control Solutionshttp://www.powertraincontrolso...2.pdfhttp://www.powertraincontrolso....html

The Aftermarket Transmission Controller (TCU) is a fully programmable transmission control system. Through a friendly PC Windows interface users are able to program transmission settings based on speed, engine load, engine speed and other parameters. This powerful unit allows users to control every type of electronic automatic transmission from Ford, Nissan, GM, Toyota, Chrysler and many other manufacturers. Automatic transmissions have been mass produced only in electronic versions for many years without a satisfactory aftermarket solution. Now there is!

I will not go into detail about what the TCU is or does, since its explanation would require another post. Basically, it allows you change the way you’re A/T runs. The main parameters being shift points, shift firmness, TCC lockup, and shift speed. It sounds simple but trust me, it’s not. It took me almost a month to tune my TCU to my needs, and I’m still not done! I credit this device for being solely responsible for eliminating most of the disadvantages with automatic transmissions. Just like any type of tuning device you’ll be tinkering with it perpetually (even in your sleep, like me). This TCU also allows for several switchable modes; such as button shifting, snow, dyno, or calibration B (also known as Bad *** mode). There is also room to program other inputs or outputs like: coolant temp, trans brakes, etc. There is so much more you can do with their TCU, that it would require its own post.

The greatest feature about PCS’s TCU is that it is universal. The TCU can be wired into any electronically controlled A/T and updated as new software is available; thus, an aftermarket TCU becomes a lifetime investment. It is the foundation for all my project cars. Did I mention I like it? Despite the cost and effort, I guarantee A/T owners will never be the same.

High-end Build Budget: Performance Transmission RebuildItems: The RE4R01A transmission, performance rebuild kit.Time: Dependent on which route you take, roughly 1-3 wks.Cost: $600-$3000



http://www.importperformancetr...#main

If you rebuild the A/T yourself you’re looking at lower costs and high quality but not the highest. These kits include all necessary seals, gaskets, filters, shifting bands, and clutches that are required when rebuilding transmissions. Most of them are stronger and more efficient then the OEM rebuild kits. Remember, this doesn’t include a valve body upgrade.

The same quality goes into it if you have it done in your average transmission shop. The only difference is you must include the price of labor, which can be up to $2000 or more.

The best option is to go with a specialty performance transmission shop. They have the right tools for the job to exploit the maximum potential of the A/T. This usually includes VB upgrades, strengthened planetary gears, and other features not included in a DIY rebuild kit. Expect to sell your soul to fund this endeavor.

Once again I suggest pulling a RE4R01A from the junk yard to reduce downtime. IPT and Level 10 will send a freight to your door to pick up the transmission and send it right back. The guy from IPT claimed once they get the transmission it takes only 20-30 hrs to finish and less than a week to ship (about 2-3wks total downtime).

So Why Rebuild: Is that a stupid question?

You rebuild a transmission; whether M/T or A/T, for the same reasons you rebuild an engine or anything else for that matter. Increase durability and power transfer is the goal of the transmission rebuild. What’s the point of having all that HP if you’re losing power on the way to the wheels? Decreased times, more HP, and more torque can be earned from rebuilding the drivetrain system.

Closing Notes: “Nothing in Life is Free”

As you can see upgrading the A/T or M/T can be terribly expensive but the automatic transmission certainly takes the cake. My recommendation is to start with a good foundation and build up from there.

Once again I restate that this post is not to debate which is better, M/T vs. A/T, but simply to discuss what can be done with the Nissan automatic transmissions. Debating transmissions is like debating drivetrain set-up. Which is better front wheel drive or rear wheel? Neither both have their advantages and disadvantages. Purest like to say anything that’s not an M/T RWD is not a real sports car. Or they right? There are many paths to the same goals. A/Ts can do ANYTHING an M/T can! This means drift, drag, road, circle, rally, straight line, or turn. Please don’t comment about “How A/T’s are only good in straight line” or “I hate my A/T”. If you read the entire post before you reply most of the common disputes have been rebutted already. This is not the intended purpose of the post but rather to share the wealth of information for those interested in the automatic transmission. Besides my car is tangible proof that you’re wrong. If you have any question, upgrades, tips, or suggestions feel free to reply.

The World’s First and Only Paddle Shifted 240SX Sponsored by Twist Machine



Special thanks to Steve Chryssos of Twist Machine whose sponsorship allowed me to reach my goals and dreams.

Special Thanks to J. Ballenger and the good people of Powertrain Control Solutions whose customer service and technical expertise transformed my dreams into reality.

Great appreciation goes out to the folks at IPT Performance Transmissions who answered the plethora of questions I had for them. I look forward to doing business with them.

Thanks NICO for letting me clutter your forums with my lengthy posts.

And to the nay sayers………………. Well, Nun Quam Non Paratus.

*Note* This post is not to discuss the paddle shifted 240SX (Shrifter SX) in detail. It is meant only as an example and is to encourage experimentation and discussion of the automatic transmission. Yes it works, yes it will be on the track, and yes I will make a detailed post about it. Just a taste folks!
Modified by moyea at 2:43 AM 6/13/2006

[CRyan]

i just spent 47 minutes reading this whole thing

AWESOME - its great to hear that A/T's are capable (or in some cases more capable) of doing things that were thought of as only M/T's doing

very nice write up - and i like the paddle shift - looks great!

[moyea]

Thats an old pic. I have since painted the Shrifter (thats Shrifter with a "r") black in order to match the interior. Once Steve and I work out all the kinks, Twist Machine will then have a production template to use with all 240sx or at least S13s. I'll post a better pic of the car and Shrifter in my next write-up.

Thanks for reading! Sorry it was so long winded but I wanted this post to become a reference for all those asking questions about their A/Ts.

[fatpringleman]

question: i know i can manually downshift/upshift in my auto... but when i downshift in a corner the revs don't match up smoothly and it jerks the car forward as the revs match suddenly. is there a way to get the revs to match more smoothly on the downshift? or are jerky shifts the only option?

a lot of times i worry that this jerk will send me fishtailing out of control in a high speed corner...

[moyea]

question: i know i can manually downshift/upshift in my auto... but when i downshift in a corner the revs don't match up smoothly and it jerks the car forward as the revs match suddenly. is there a way to get the revs to match more smoothly on the downshift? or are jerky shifts the only option?

a lot of times i worry that this jerk will send me fishtailing out of control in a high speed corner...

Good question. But....... I need a little more info. What are you driving? (I assume a 240) What kind of course style driving (drift, autoX, open track)? What gears are you in? Remember to read the owners manual and FSM to know the safe speeds to change gears in.

To start off, make sure the transmission is ready for action. Its good? Ok, move on.

All trannys will jerk and drop revs when down or upshifting. In some performance M/Ts it feels like the transmission is going to break right off the car. This is normal! What you are feeling is the clutch plates disengaging and reengageing. If your in 4th and you feel a slight jerk, this is your TCC locking up. All this is normal to some extent. If its really really strong or it does it when driving normally, there may be a problem.

Obviously if the clutches are disengaged revs will drop during upshifts unless you keep pushing the gas, then it'll rev up and drop back down when the gear catches. In the downshift the car will jerk and rev up. The key to driving a A/T like an M/T is to DRIVE AN A/T LIKE AN M/T. There are two methods of attacking a corner which produce the best results (M/T or A/T):

1) Before entering a turn you need to do all the downshifting, braking, CD changing, soda drinking or whatever before turning the wheels. Most pro-drivers know what gear they need to be in for each cornor so you should do the same. Knowing your vehicle is essential to knowing what you can do with it. Example, your in 3rd (OD off) from the straight away coming into the cornor at about 85ish@4-5000rpm, you'll need to brake till you get to a safe speed/rpm range(55ish@ 2-3000rpm) then make the shift to 2nd. Continue through the turn until you exit, then upshift to 3rd. For the drift its the same, just at a higher rpm (5-6000). This method provides the best traction, times, and safety.

2) Second method involves entering the turn at a higher gear and then downshifting to powerout of the exit. This method is very brake intensive. Used mostly by beginners who cant handle all the foot work involved in the first method or for long sweeping turns where downshifting+braking is unecessary.

So yes, the jerks can be normal. No, you shouldn't be shifting in the middle of a turn. Reducing the jerks can be done with changing to a better fluid, adding a cooler, or installing an aftermarket TCU.

Personally I calibrated the TCU to provide firm upshifts with almost no jerky downshifts. This keeps the car from shifting too much weight to the front allowing a more flatter braking feel to the car. I also tried a technique called heel-to-toe-to-finger which is the same as heel-to-toe only I shift the gear(paddle shifter) with my pinky.

Let me know if that helped and watch videos to see how the pros take a turn.

[fatpringleman]

from what i gathered about your reply, the only way i can really get softer/smoother downshifts is to modify my automatic (which can be very expensive). i have been downshifting my auto (95 240sx) before the turns, like you said, in order to avoid uncontrollable shift of weight to the front. then apply power during the turn to balance the under/over steer through the throttle...

the thing that intrigued me is... is there a cheap or easy way that i can modify my A/T to have firm upshifts but smoother downshifts?

thanks for all this A/T chat... gives me more things to think about in the upgrade/mod path.

maybe the better question is, can i reprogram the stock TCU to achieve these goals?

[moyea]

As it stands, there are not many cheap options for import A/Ts. If you had a GM I would say buy a shift kit (about $80). But, I'm unaware of such a cheap kit for Nissan.

the thing that intrigued me is... is there a cheap or easy way that i can modify my A/T to have firm upshifts but smoother downshifts?

maybe the better question is, can i reprogram the stock TCU to achieve these goals?

The only free/DIY option I've seen so far is this: http://jime.homeip.net/DR%20Mod.html The accumulator mod will certainly quicken upshifts but I'm not sure about downshifts. I assume your complaint is the downshift 3rd<=>2nd. The TCC has a lot to do with that. Sorry, nothing you can do with a stock TCU. Unfortunately, expense is one of the curses of the A/T. It can be worth your time if you're willing to invest.

Unless your some kind of super genius programmer because its a computer similar to the ECU.

[supreamS14]

a/t = alot of mass+heavyer+not every 1 knows how 2 drive stick!m/t=lighter+less mass=less stress on the motor+FUN FACTOR auto{ }manuel

[98koukile]

a/t = alot of mass+heavyer+not every 1 knows how 2 drive stick!m/t=lighter+less mass=less stress on the motor+FUN FACTOR auto{ }manuel

Why is it that no matter how many times someone says they're just doing a write-up, some ******* has to flame what they're saying. Just post your I love manual crap in a manual post, obviously people agree with you.

You drive a 2.4 liter "sports car" you don't have enough power to lose anything worthwhile from driving an auto anyways

[RazoE]

a/t = alot of mass+heavyer+not every 1 knows how 2 drive stick!m/t=lighter+less mass=less stress on the motor+FUN FACTOR auto{ }manuel

You brought up and old thread for this lame ****?

my 240 was auto and i loved it...

my Supra's 5-speed and i love it more...

while im getting another 240 soon, it'll definitely be stick..

but still Automatics have their advantages..

[slipstream_pnoy]

wow this is a very good and informative thread... finally people can really see wats autos can really do... (i love it ) now if i can juss have money to buy everything.... ohwell save save save............. neways love the thread good job dude