KC95SC400

iTrader: (3)

I might try it again. How much did you have to adjust it?

I did get the solenoids but they were wrong. I then found a great deal on a used 96 trans with half the mileage of mine. Plan on putting that in on Friday after doing some mods to it. We'll see what happens.

KC

forcefed86

Very slightly 1/8 to a 1/16 of an inch took several trys to get it right. I ran across another auto 2jzge with the same issues on the AEM forums. He claims replacaing the solinoids fixed his shifting issues. Sure wish you'd try those before throwing in another trans... otherwise we may never know...

KC95SC400

iTrader: (3)

Well, I was intending to replace the solenoids. But, I got the wrong ones. Then I found the deal on the trans which is cheaper than new (even aftermarket new) solenoids.

I'll be installing it hopefully on Friday. I plan on modding it first, hopefully I'll keep myself from rushing and take some pics of the mods.

If the newer, modded before boosting on it trans doesn't fix the problem, then I think a shift kit would be the next move. I think telling the trans to shift earlier, by whatever means, is putting a bandaid on the problem rather than fixing it. I think it's possible the hydraulics are just too slow for the power level.

I'll update soon.

KC

BigManne

iTrader: (3)

i have the same problem as do many 1jz auto guys. ecu pulls timing to prevent braking the trans. i have been researching this for a while and i have not come with a real answer to the problem. planetsoarer guys have discussed the problem also. i wish there was an answer out there.

sc250tt

There is.... .Go 5 speed .

KC95SC400

iTrader: (3)

I have read that the ECU does pull timing during a shift. There are a few answers to that problem and I don't think it would / should cause bouncing on the rev limiter.

I'm hoping this newer transmission will help for a few reasons. First, I'm going to up the pressure and shim the accumulators before it goes in. Second, in the 96 SC400 new model info from Toyota it is said that slight changes were made to the transmission to improve shift timing. Doesn't say what though...

Now my current transmission has gone through way over 50 track runs and 7-8 months of daily boosting before I did anything to improve it. This problem wasn't really very bad until I put on the headers and installed a complete mandrel 2.5 inch dual exhaust. I'm hoping that the 96 trans with about half the mileage that will be modded a bit before ever being abused will fix the problem. My fingers are crossed.

As far as the timing retard issue...a shift kit and / or the mods I'm doing should in theory make the transmission shift fast enough to keep the ECU from retarding the timing. Also, a TCU and / or an aftermarket EMS should fix the problem.

I'll update with soon.

As far as putting in a 5 speed, I really like auto better for daily driving and auto trans cars are much faster for racing use, when they shift correctly.

KC

KC95SC400

iTrader: (3)

So I was planning on installing the new(er) auto today but apparently FedEx has lost it.

How you lose a giant blue rubbermaid container that weighs near 150lbs, I don't know. They told me it's possible the label came off, they put a trace on it. It should be, at very least, in Charlotte according to the tracking info.

I was also hoping to get back on the dyno today, after the install.

Sigh, I'll update when / if I ever get it.

KC

KC95SC400

iTrader: (3)

So I might be getting the trans tomorrow. If it arrives early enough, I will likely be modding it and putting it in. Possibly running the car on the dyno as well.

There is only so many things that can be causing it. I think I've listed these already but I'll do it again.

1. An interanal trans problem. Looking at the clutch application chart, my biggest suspects are the foward one way clutch which is only held in second gear, it's allowed to over run in all other gears. Or, the second brake. I'm not an expert but neither of these seems likely. I'd try to explain but I get confused myself thinking about it.

2. ECU control. This seems very likely for a couple of reasons. I would think that no matter what, it takes a certain amount of time for the hydraulics to move the shift valve(s), apply the clutch packs, ect. I also would think that this is considered when the ECU is programmed at the factory. For example let's say the ECU commands a shift at 6000 rpm when at WOT. It might take three tenths of a second to complete a shift. It might take an unmodified car half a second to go from 6000 rpm to redline. It might take a car with significantly more power than stock two tenths of a second to go from 6000rpm to redline. Redline is reached faster than the auto can physically shift. Possible I think. Fix for this would be a shift kit to make the trans shift faster and / or a TCU.

The whole timing retard thing. I don't really buy it personally. I don't doubt that the ECU retards the timing to reduce engine power I just don't see how this would prevent the shift. Seems like bouncing on the rev limiter would do more damage then shifting at full power. The ECU cuts fuel while bouncing on the limiter, I logged it once and saw my AFR go 18 to 1 with 10-11 psi of boost. It's amazing I haven't blown the motor yet. I also think that it should shift better with reduced engine power. I do know for sure that my car will shift much better (still not great but better) if I let off the throttle a little before it shifts. Fix for timing retard would be an EMS. Now that I think about it, I think forcefed86 is implying some guys on the AEM forums have the problem so seems like the timing retard is a non issue as far as shifting goes.

3. Hydraulic problem. Bad solenoid(s), clogged filter, weak pump, sticky shift valves, check *****, internal leak and who knows what else.

Again, I'm not an expert, just my opinion.

Now in my case, if I put this newer trans in and the problem is gone then I know at very least something inside of my current trans is bad. I probably won't be able to say what with 100% certainty though. It should be noted that I beat on my current trans quite a bit before I did any mods to it.

KC

IS_250

iTrader: (2)

in for the updates....

KC95SC400

iTrader: (3)

Did a few things today, finally got the transmission. To re-cap, I have a 95 and this trans is from a 96 with about half the mileage on it.

Things I did...

I shimmed the b-2 and c-2 accumulators on the new transmission using washers. I had used 7 washers on the old trans, bumped it up to 8 on the new one. This makes .6 inch or 15.24mm worth of shim. At this point, the accumulator travel is only like 1/2 inch or less. I also raised the main line pressure via the regulator adjustment.

I took the filter out of the old trans for install on the new one since I had just replaced it a few weeks back. I also used the pan from the old trans, the pan on the new trans was damaged. I also used the throttle valve cable from the old trans since I damaged the cable on the new one by accident. I also replaced the front pump / converter seal. I used all of the sensors that came with the transmission.

I finally removed my EGR pipe.

Installed the new transmission.

---------------------

A few notes..........

I've read that the dragon converters are painted with a special paint that changes colors with heat, mine looks the same as it did when I first installed it way back when.

As far as I can tell, there is no difference between the 95 trans and the 96 trans, internally or externally.

On my first and only test drive, I did not have the throttle valve cable adjusted quite as tight as I had it on the old trans.

I did not reset the ECU.

---------------------

Results...........

I'm not going to say it's totally fixed but there is definitely a HUGE improvement. With the old transmission, the engine would bounce on the rev limiter 10 times or so. Sometimes it would be so bad that I could actually feel the car lose forward momentum, I could feel the weight transferring back to the front.

I drove it home from my work which is about 11 miles away. Due to traffic and low speed limits I only got three chances to try it. All three times I stomped the gas from about a 20 mph roll. The first time it bounced 1 time followed by a quick shift. The second time it bounced twice followed by a quick shift, I'm pretty sure my tires were spinning on this attempt. The third time it did not bounce at all.

For light to heavy driving (but not WOT) it shifts MUCH better. First to second shift is no longer mushy. Shifts quick and tight. This is also true for 2-3, 3-4 and tq clutch lock-up.

Of course, this is only one test drive, I will report more when I have more to report.

---------------------------

Some other notes.........

After I got home, I readjusted the throttle valve cable to where I had it before.

I'm likely going to bump the TPS a little before I drive it again.

I removed the valve body on the new trans on the bench. I'm not convinced it's any easier to do on a bench compared to on the car.

For some reason, when using the shifter, the new transmission goes through the gears (PRND2L) mush easier.

I will likey do a full flush within the next few days, couldn't hurt.

I think that's it.

I'm horrible at taking pictures, I work on cars for a living so I have a hard time stopping to take pics. I just want to get the job done as fast as possible. I did take a couple of the accumulators.

Let me know what you guys think.

KC

In this pic I have already removed and shimmed the b-2 accumulator. This is how it sits with .6 inches worth of spacers.

KC95SC400

iTrader: (3)

Here, the c-2 accumulator is being removed. You could shim the c-o (left most) if you wanted to, but it's for the 3-4 shift. I don't really think it's needed.

KC

forcefed86

Awesome... defiantly play with that TPS. It was night and day on my factory ECU car. My trans finally let go this weekend on a few sporty 25psi passes. The new 66mm turbo sure felt good! I have found a local here in wichita thats has built a few high HP supras. So it's getting removed and taken to him this weekend. He's going to check over the valve body and replace all the clutches and bands. Shim up the pressure and just look everything over for $750. He tells me once properly "modded" They will hold the power for a year or two. Then it's rebuild time again. But I'm not going to drag race mine anymore so he said it would last quite a bit longer. It's the 2nd to 3rd that always goes....as we all know. So he suggests keeping it to 3rd gear WOT highway pulls.

Good luck let us know how it goes! I'll create a thread on mine as well. Once I open her all up maybe I can expose all BL secrets to you... I'll check there line pressures and We'll see if they even shimmed the accumulators....

What fluid are you using BTW?

KC95SC400

iTrader: (3)

Hey, sorry to hear about your transmission. Any idea of your power level at 25psi? $750 is a good deal for a performance auto rebuild, whish I was closer.

On mine, it definately is better, even for normal driving. On the TPS, just to be sure, you turned yours clockwise correct? Do you know if this raised or lowered the voltage? Turning mine clockwise raises the voltage, doesn't seem to make sense that it would shift earlier with higher voltage. I haven't played with it more yet but plan to.

KC

PS, sorry to be so breif, at work..LOL.

forcefed86

No prob. This trans builder is assuming the BL trans already has all the goodies/upgrades. Sprags, valve body, accums, extra cluth etc... He's just looking it over and installing new clutches. If it needs any "mods" it will be expensive.... Probably pushing 560 wheel? Not sure really. Made almost 500 crank on the 60mm @ 26psi.

It will shift earlier with higher voltage becuse the ecm uses the TPS as a load sensor for line pressure (Which makes no sense) It's designed to raise the trans pressure with a higher TPS load signal. More press in the valve body equals sooner shifts. So if your car is clunking into gear when going from park to drive the line pressure is already up. Which in turn will cause you to shift sooner. If you get a smooth P to D transition your line pressure is down and it it will shift higher in the RPM band. (like is is suppose to).

What you are doing by advancing the TPS is raising line pressure (good thing IMO) at the expense of clunking into gear and grabbing clutches sooner and shift earlier.

Dunno if that makes sense, I'm at work too gotta type fast when they're not lookin!

KC95SC400

iTrader: (3)

Wow, 560 + - wheel, daily driver?

Your explanation makes sense, but I'm confused on one thing..

Untill 98 (I think) the ECM has no electronic control over line pressure...other than maybe by using the accumulator pressure control solenoid, which I have disconnected.

Your transmission probably doesn't even have the accumulator pressure control solenoid, don't think it was used in SC3's unti 98 (again, I think).

KC