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oxford1327

Manual valve body in stagea auto

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Hello all, I am seeking information on real life experiences of having a manual valve body in a series 2 stagea, as in how harsh are the changes when just tootling around town etc. 

I've had a manualised auto before but it was in a Torana hatch with a 350 chev and power glide, so it be vastly different being a 4 speed. 

I already have a stage 2 shift kit installed from MV Automatics and am currently sitting at 295awkw and the new ecu is having an occasional fluff around, so have been contemplating the manual valve body. 

Look forward to the potential flame show coming my way. 

Cheers 

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On 5/4/2021 at 3:06 PM, oxford1327 said:

Look forward to the potential flame show coming my way. 

 OK

https://xyproblem.info/

Maybe specify whether you actually want to have to stir some lever all the time under full line pressure or whether it's intended as a stop gap measure for your real problem.

What do you mean by the ECU fluffing around?

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4 minutes ago, zoomzoom said:

 OK

https://xyproblem.info/

Maybe specify whether you actually want to have to stir some lever all the time under full line pressure or whether it's intended as a stop gap measure for your real problem.

What do you mean by the ECU fluffing around?

As stated I have had a manualised trans before and it was fine when under heavy acceleration, however it was only a 2 speed, hence I asked how much of a Pita is it gonna be with a 4 speed around town, and shifting gears/"stirring levers" isn't the issue. 

With reference to the ECU fluffing around, it is flaring on up shift between 2nd+3rd when cold, then sometimes between 3rd 4th in both directions when at running temp as the Trans Control Unit isn't accurately communicating with the ECU and it doesn't seem to know whether to keep the converter locked up or release etc

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And as a side note, yes the entire set of solenoids have been replaced with brand new units about 15000klms ago which was about 2000klms after the shift kit was installed as it was recommended by MV automatics as well as my local trans builder/service provider to do the solenoids as well just because they're 20+ yrs old

 

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Any other variables like how much throttle you're giving it when the gears flare?

Once the ECU actuates the solenoids, gear flaring really becomes a mechanical problem. The auto control should be similar to a series 1, in that the line pressure is determined by throttle position, not how much torque the engine actually produces. Once you start introducing tuning and different turbos, you can imagine the engine producing more torque than stock at a given throttle.

The type of transmission fluid can contribute to flaring. Ironically I tried the genuine nissan fluid years ago and it flared on gearchanges (back when I had a stock valve body), this was solved when I used transmax z.

In terms of dealing with increased torque from the engine, the standard line pressure ballast resistors should be replaced with a higher value or better yet a 2 step system works well, if you have an output from your ECU available (for example I have 2 resistors to vary the resistance once the manifold pressure reaches a few psi of boost)

Standard value is around 15ohms from memory, which I increased to 25ohms at low throttle, then switches to a couple of kilo ohms under boost, essentially maximising line pressure. Gets rid of flaring at part throttle with boost.

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4 minutes ago, zoomzoom said:

Any other variables like how much throttle you're giving it when the gears flare?

 

Generally only flares between 1st to 2nd, and 2nd to 3rd when under light load and cold, once it's warmed up and sink the hoof into it it shifts as it should, it's like it can decide to shift and is holding out for more throttle, the 3rd to 4th in either direction once warm and under light throttle cannot decide if it wants to shift or just coast with the convertor unlocked, well that is how it sounds and feels to me 

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Just called trans service and they've said box is currently out of the car being diagnosed and do far has shown signs of bands slipping, and potential clutch pack wear, so they're being replaced asap and uprated flex plate being installed as well when it goes back in

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If you're willing to sink the funds into a box rebuild then I'd be looking at an aftermarket trans controller too. Apart from retaining the choice of auto or manual gear selection, variable line pressure, and the ability to tweak all the shift and lockup points is a benefit once you've tuned the engine. Also I highly recommend retaining and optimising ignition retarding logic on gear changes, to maximise the life of the box, reduce shocks to the rest of the drivetrain, not to mention the inhabitants of the vehicle. 

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8 minutes ago, zoomzoom said:

If you're willing to sink the funds into a box rebuild then I'd be looking at an aftermarket trans controller too. Apart from retaining the choice of auto or manual gear selection, variable line pressure, and the ability to tweak all the shift and lockup points is a benefit once you've tuned the engine. Also I highly recommend retaining and optimising ignition retarding logic on gear changes, to maximise the life of the box, reduce shocks to the rest of the drivetrain, not to mention the inhabitants of the vehicle. 

Cheers for the knowledge, who makes these control boxes and how many first born will need to be sacrificed for one? 

Also, how much buggering about would you expect to allow for set-up, and was it a drawn out process to get yours to work at an acceptable level or is it something that has a depth of knowledge available? 

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9 hours ago, oxford1327 said:

Cheers for the knowledge, who makes these control boxes and how many first born will need to be sacrificed for one? 

Also, how much buggering about would you expect to allow for set-up, and was it a drawn out process to get yours to work at an acceptable level or is it something that has a depth of knowledge available? 

@Kinkstaah
should be able to answer some.of those questions.or all of them.

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I used a TCM PCS 2000, which has since been superseded by other TCU's that that company makes.

Honestly the gearbox itself (in R34 GTT form) has something like... 8? Wires going to it. It was remarkably not-that-complicated once you have it all out infront of you and a fair understanding of what wire goes where (i.e have the service manual handy).

More modern engine ECU's can also control an automatic gearbox. These would actually be my pick because you can then have the engine ECU know about shifting and perform additional functions. I don't know off the top of my head which ECU's manage a motor AND an additional auto gearbox but I would wager the higher end known options do (i.e haltech, link etc)

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15 minutes ago, Kinkstaah said:

I used a TCM PCS 2000, which has since been superseded by other TCU's that that company makes.

Honestly the gearbox itself (in R34 GTT form) has something like... 8? Wires going to it. It was remarkably not-that-complicated once you have it all out infront of you and a fair understanding of what wire goes where (i.e have the service manual handy).

More modern engine ECU's can also control an automatic gearbox. These would actually be my pick because you can then have the engine ECU know about shifting and perform additional functions. I don't know off the top of my head which ECU's manage a motor AND an additional auto gearbox but I would wager the higher end known options do (i.e haltech, link etc)

I have a link G4X StormX ecu installed and that is what we think is giving the trans control unit the shits, there has been some development at link and haltech to start basic control circuit etc but it hasn't been refined as yet so there's not a lot of troubleshooting guidance so far, I've sent off an email to a TCU mob that list jatco RE4 +RE5 boxes however the model RE4R01B is not shown, so I've asked if it is supported with their unit, awaiting the response. 

I will look into the TCM PCS model range and see what I can dig up. 

Cheers again for the help 

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Yeah I could not find ANYTHING, at ALL for the RE401B on anything, at all.

It wasn't listed for the TCM PCS range either, but it didn't need a lot of smarts, and the TCU that we got was a universal, truly standalone one. In the end it just wanted speedo, tach, and the inputs on when to change gears (pretty much). You could set up the auto shifting and setup a full manual mode. You could change line pressures and such if you really wanted to, but it was hooked up with pretty much max pressure all the time. It had full control of the box and you could configure things like shift lockouts. However you did have to blip the throttle when shifting down - going from 2nd to 1st at 60+kmh would lock up the rears if you didn't blip it.

Mine was originally installed by DTM Autos in Geelong - I only really got my hands dirty with it when we re-shelled the car, and I had a GTT to work with instead of the original GT N/A car, so all the wiring for the TCU had to be worked out again! That said, it was a lot simpler than we thought, and we had it going in a couple of hours actually, with just a friend and me on the nature strip of all places.
 

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2 minutes ago, Kinkstaah said:

Yeah I could not find ANYTHING, at ALL for the RE401B on anything, at all.

It wasn't listed for the TCM PCS range either, but it didn't need a lot of smarts, and the TCU that we got was a universal, truly standalone one. In the end it just wanted speedo, tach, and the inputs on when to change gears (pretty much). You could set up the auto shifting and setup a full manual mode. You could change line pressures and such if you really wanted to, but it was hooked up with pretty much max pressure all the time. It had full control of the box and you could configure things like shift lockouts. However you did have to blip the throttle when shifting down - going from 2nd to 1st at 60+kmh would lock up the rears if you didn't blip it.

Mine was originally installed by DTM Autos in Geelong - I only really got my hands dirty with it when we re-shelled the car, and I had a GTT to work with instead of the original GT N/A car, so all the wiring for the TCU had to be worked out again! That said, it was a lot simpler than we thought, and we had it going in a couple of hours actually, with just a friend and me on the nature strip of all places.
 

Awesome work, thanks heaps for the knowledge, truly appreciate it and will try to put it to good use, I'll have a chat with mv automatics and my tuner to see what they can find/recommend etc, and show them this thread to have a kick off point. 

I'm gonna start researching as best I can in the meantime and smashing the inboxes of manufacturers to see what shakes out. 

Cheers 

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Have heard back from 2 controller manufacturers and neither support the RE401B, they both support the A model but the B has extra solenoids and harder to get around electronically apparently. 

So the search continues, next step is to get hold of MV and see what they can suggest 

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The kit that I used specifically only mentioned the A too, but the B was no issue.

Maybe contact DTM in Geelong (they're closer than MV) and they may be able to assist/recommend something.

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The kit that I used specifically only mentioned the A too, but the B was no issue.

Maybe contact DTM in Geelong (they're closer than MV) and they may be able to assist/recommend something.

Cheers, will look em up and hit em up

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The kit that I used specifically only mentioned the A too, but the B was no issue.

Maybe contact DTM in Geelong (they're closer than MV) and they may be able to assist/recommend something.

So yours was a B? 

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Mine was the B, the B is what is in the R34 GTT. I'm not 100% certain what the A is actually in. I've read the "A" is the non triptronic version, but I've also read the "A" version is also triptronic in the non turbo auto skylines.

They have a triptronic auto but it is not the same internally. I sent a melted/destroyed to hell MV built auto which was originally the GT Non Turbo auto to DTM.

I also sent a stock GTT auto to DTM and asked them to build it. They said the Turbo one was substantially different to the N/A variant, so not a fault of MV that it melted itself, it just had a lot less of a base to work with.

There was also the option of fully manualizing it, which is simpler, and cheaper, and more direct - However I quite liked the idea of the steering wheel buttons working, and the ability to "Just put it in D" with a lazy, smooth mode, then an extremely aggressive mode in "Manual" mode with the wheel buttons.

The latter setup requires the TCU to drive it - When they said it was doable I pulled the trigger on doing it that way, and retained the stock shifter, shifter buttons, etc which was nice.

(none of this is better than being manual, though, if it's an option, do it)

The shifts with the max line pressure the modified body could provide weren't actually that savage, more of a little firm bump than being kicked around etc. It took the power and lasted ages (and I sold it in the end, as a kit!) but keep in mind the total cost was in the 5-10k region all up, in a roll in, "hmmm how are we gonna do this", and drive out scenario.

As always, decide what you want to do with the car, honestly before doing anything. The stock ECU running the gearbox actually does a pretty decent job in regard to requesting line pressure in a R34. The benefit of aftermaket control was/is

a) Using a standalone ecu, you could consider changing your engine to run Nistune etc.
b) The ability to shift less harsh than the OEM ECU would shift for you once you massively uprate the physical gearbox capacities.

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I am fine with not having the steering wheel buttons working, and no issues with having to move the shifter etc, was more about dulling the thumping between changes, especially on down shifts. 

Will see how it goes with new clutch packs and band for now, but full manual valve body is looking more and more likely in the future 

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