eefmydee

So I just wanted to share my experience since I have never heard of anybody have any problems with this mod before (or at least no one ever posted it up on the forum). Before I go about writing all of this up I just want to list a few important things.
1) I use the car for autocross and late night street runs on curvy roads.
2) Tranny is A340E
3) Prior to doing this mod I did not know much about automatic transmissions just manuals (never had the need to learn until now).

Perception: When I was reading about this "modification" I was under the impression that there was a dampener in the transmission that was ironing out all the roughness in the shifts because this was a luxury vehicle. Obviously me wanting performance and faster shifts I read on. Another name for this is the anti-squat wire. The idea was to cut the wire and the transmission would get more lock-up on the clutches and it would give you a better holeshot performance.

Reality: What the wire actually controls is the 4th solenoid in the transmission via variable voltage (pulse width modulation). This is really important because this controls how much pressure will end up acting on the clutch packs to move the vehicle. Too much or too little will cause problems.

Explanation: So there are a bunch of pathways in the transmission in the valvebody and when the solenoids re-route the fluid in these passages it will apply pressure in the correct clutch packs. 3rd and the 4th solenoids in this transmission are controlled with variable voltages and will vary the position of the valve. 100% Duty cycle = 12 volts and 0% duty cycle is 0 volts (remember this!). I have seen many people data log transmissions and the solenoids on these transmissions never hit 100% or 0% duty cycle. Why? The reason is because these pathways are one way in and one way out. 0% means all of the fluid is going to the clutch packs and 100% means nothing is going to the clutch packs. When the solenoid starts reaching lower duty cycles it is closes the valve to make pressure but will never reach 0% duty cycle because as I said it is one door with a two way street. The excess fluid that ends up coming back out gets bypassed in a hole in the valvebody and returns to the oil pan.

What happens when you cut the wire? : YOU WILL **** YOUR ****! The wire you cut is to not let the solenoid move from the 0% duty cycle position (when the solenoid is disconnected it is naturally in this position from the start). You will have an overabundance of pressure build up and will eventually lead to failure. Surprisingly it took a while and that was with a bunch of abuse and a few drag strip runs as well.

Current Symptoms: What my 92 sc400 has started to do is whine every time I turned it on when the vehicle is cold (does not shut up until it warms up completely). If I put it in gear when the car is cold the shift into gear is the equivalent of doing professional bull riding type of buck. Also it will not shift out of first if it is not warmed up and my neighbors don't like it because I have deleted resonators. Recently it has started slipping and grabbing in first gear like if i'm clutch kicking it in a straight line. I have also lost MPH. In 4th gear at 3000 rpm I should be doing 90 MPH but now the car is doing 84 MPH at 3000 rpm. I have done 4 flushes in 40,000 miles and all have been with Redline D4. No it is not the fluid because the only thing that has changed has been cutting the wire (which I have on a switch). I know for a fact I have solenoid failure but I believe I have now ****ed the clutches. Please Note: I did a tranny flush once when I bought the car and with 140,000 I was surprised to find next to nothing worth of shavings and the filter looked new but I did the flush and changed the filter anyway (fluid was red as ****). Did another flush with no filter and still red. I did the mod after the second flush and when I decided to do the 3rd flush the tranny was already acting weird so that's why there was a 3rd flush. The filter was clogged and how brown and dirty the fluid was along with the pan was unbelievable but it was already too late.

Before the 3rd flush I went to the drag strip. Remember I had this on a switch so I had the switch "on" which is running with the solenoid on, my run was 15.5. And the run with the switch "off" disconnecting the solenoid was 15.5. So as you see it did nothing but break the tranny. I take full responsibility for breaking my car and if I had cared enough to really understand I would have taken the time to research like I had done many times before and made sure this was a legit mod. I should have known that a mod that cost $0 is worthless.

I made this post to be informative and to educate people on this mod and automatic trannys. Please next time you post something about mods and that it cost $0 dollars keep that **** to yourself and stop passing on bad info which damages cars and community. What is surprising is the guy who "found this mod out" really thought he had something and he put serious effort to pass around bad logic.

t2d2

iTrader: (8)

It sounds like you did your research, but have you ruled out the possibility that the tranny failure is due to the high stress of racing it? You connected a lot of the dots, but it still sounds like a bit of a leap of faith.

eefmydee

That is a very good question. It would seem that all the abuse would make it break now but I was a lot more abusive on the tranny before this mod. I decided to go back to school and I have less time to drive the car, I dont go out as much, I dont do events as much as I use to (or right now at all) and all I do is drive highway to visit my parents. For the record I havent done any events this year. The mod was this year, the failure was this year and the brown fluid and clogged filter was this year. I cannot rule out the previous abuse because it could be stacking up against me now and not know it but the way the events have unfolded I feel it is unlikely. This mod was max 3 months ago. I have had the cars for almost 4 years of pure spanking but I also did the maintenance early. (for example I changed the spark plugs, wires, distributor cap, rotors every 20,000 miles and that was twice already.) That is the maintenance treatment on my vehicle so I highly doubt I am wrong. plus 4 tranny flushed in 40,000 miles. I'll let you be the judge.

t2d2

iTrader: (8)

That makes it even more puzzling, and seemingly coincidental. I could probably be convinced that the mod is bad for long-term longevity when tracking the car, but if yours happened when you weren't doing so, then why hasn't anyone else reported similarly catastrophic results? I don't buy it that no one else has been willing to speak up. (I don't mean that in a rude way, just that it doesn't sound plausible.)

eefmydee

I dont know if you are apart of any SC communities in your area but I am. Im on three closed facebook groups in florida and go out to a specific SC meet here in orlando and no one ever speaks up or says anything. Most people do manual swaps anyway. I havent done events this year but still beat on the car going out to meets when I can. If you dont want to believe me thats your problem. I just want to save people the bull****.

Have you personally done this mod on your SC? Do you know anyone who has? Not online a person you can call and meet in person right now?

Also all your saying is it is not plausible because I am the only person who has spoken up. Where is your experience? Have you figured out how these specific transmission work? Your sir are blowing smoke. You obviously didnt understand the function I described. Do me and everyone else a favor and re-read what I wrote about how the solenoids work. I you pressurize a space with no outlet you get a bang. Is that not simple enough?

t2d2

iTrader: (8)

Dude, chill. All you're doing now is making people question whether you did something hotheaded to blow the tranny.

Yes, I have done this mod and know others who have. I wouldn't have had any reason to chime in otherwise. You're the only one who has reported the problem that I'm aware of.

I gave you credit in the first reply as appearing to have done your research.

eefmydee

Okay well anyone feel free to chime in anytime. What do you do with the car and have you done the mod? How long have you had this "mod"? Do you leave it off the whole time or do you have a switch? Please anyone.

eefmydee

And also does anyone have drag times of them using this mod and the time slips to accompany those runs? I will post them up when I get the time to show you the difference (which is nothing).

eefmydee

Kitabel. You are correct. I was getting my terms mixed up there. It is analog meaning variable voltage. Thank you.

I do not know what temperatures I reached because I do not have a temperature sensor. But I had a transmission cooler with a fan that was rated for I believe 500cfm. The size of the cooler is 9x11x1/2 inch. (thickness I cant remember correctly but I think it was somewhere close to 1/2 inch).

eefmydee

MY CAR IS #174 IN THE RIGHT LANE ON BOTH!
The slip on the left is with the Solenoid disconnected. The slip on the right is solenoid connected. There is no gain at the strip at WOT.

For the people who have done this mod you know that when you do disengage the solenoid that the shifts are a tad quicker (up and down) but that is all you gain. When I get the transmission out I want to take it apart and see what happened though I cannot blame all the wear on this mod I will be testing the #4 solenoid to see if it has been damaged.

t2d2

iTrader: (8)

Those slips look like it helped you at least a little bit. You were faster on every segment despite a slower reaction time. Whether it's a significant amount is up to interpretation, but there's definitely a difference.

eefmydee

The faster time is on the right and that is with the solenoid CONNECTED. I went slower with the solenoid "off". 3 hundreths of a second is the difference and that is not something I would call a significant difference unless I was .5 seconds faster instead of .03 seconds faster. If I was doing .03 seconds faster and I was already doing 5 secs in the quarter I would agree but on a stock car in the 15 seconds range thats a joke. Moral: There is no performance to be gained doing this mod. end of story.

Also the engine is stock. No power adders, no tranny upgrades no lsd, it is completey stock in the drivetrain. Just added the tranny cooler. I have seen many people take these trannys to 400hp without breaking them so clutches being to small is probably not the cause either. A malfunction with solenoids will definitely do so.

t2d2

iTrader: (8)

My bad, I thought they were reversed. In that case, your job is to explain to the skeptics how faster shifts and a faster reaction time resulted in slower splits... Something else had to have changed, such as weather or road conditions, how much throttle you gave it, health of the engine and tires, etc. Maybe you didn't push it as hard the run you were behind in? Are those the only head to head comparisons?

eefmydee

I should have been more clear. For me I felt slightly quicker shifts under normal driving conditions up and down but we proved that WOT it doesn't matter and I couldn't tell the difference in shift speed at WOT. But for downshifts for example: If you manually moved the lever from 3rd to 2nd it would shift down a tad faster as well. Like I said .03 difference is NOTHING TO TALK ABOUT. There is no difference in time. And yes only head to head comparison.

I sort of dont understand how you cant rap your head around it.

At slower speed and less throttle position the duty cycle should be higher to relieve pressure that is un-needed but when you give it more throttle the duty cycle goes lower giving the clutch packs more fluid (keep in mind that with less throttle position you are not transferring a large amount of torque through the transmission and you do not need to put as much pressure on the clutches to keep them from slipping) . Now if you had the duty cycle at 0% then you would have mad pressure all the time and make slightly faster shifts because you already have a lot of fluid flow that is coming in unrestricted (basically). If toyota tuned the duty cycles to be 50% while crusing and your at 0% at crusing then yea you are going to feel a difference when the tranny shifts under normal circumstances. But if the duty cycle is near to zero (stock) at WOT then you gain nothing because the valve itself is close to the same position on or off. Over pressurizing the clutches doesnt do nothing but create more heat and heat kills automatics.

t2d2

iTrader: (8)

Makes sense if correct.

Most people probably aren't pushing their stock trannys at 100% with the mod.