Trans resistor

Devilman · #1 04-13-2010, 12:06 PM

What is the best way to replace the transmission resistor in the engine bay? aside from going go-go gadget macgyver and modding up something that would make the professor on Gilligan's island envious. I'm assuming there isn't a brick and mortar that sells them anymore (not a common item)

A kick in the right direction would be appreciated

-DM

1986nate · #2 04-13-2010, 12:10 PM

Are you saying you need a replacement for yours? I have a couple extra and I'm sure there are others that have spares.

taylorbr · #3 04-13-2010, 12:23 PM

I have a spare as well (it's from a Lego, but it still works fine).

Devilman · #4 04-13-2010, 12:40 PM

Quote:

Originally Posted by 1986nate

Are you saying you need a replacement for yours? I have a couple extra and I'm sure there are others that have spares.

yep i need a replacement. Is this the same nate that went to massanutten?

anywho...cost+shipping?

thanks for the replies,btw....

DM

gbianchi · #5 04-13-2010, 12:42 PM

I say go for it on the professor project, there is a how to some where here, don't know where though..........G

nexus_7 · #6 04-13-2010, 12:55 PM

I need one too. send me a PM...Thanks

PaulCa13 · #7 04-17-2010, 07:03 PM

Another option is to use the vacuum-assist module from Smallcar Performance:
http://www.smallcar.com/index.php?di...08e2b40e48eec7
It's a pretty inexpensive ($60 or so) item that bypasses the resistor and uses vacuum to somewhat improve shifting.

I used one for a couple of years before replacing it with a TCU add-on module. If anyone wants my old one, they can have it for $35 + shipping from the Seattle area.

You can reach me at paulca13@yahoo.com if you're interested.

kwren · #8 04-17-2010, 07:46 PM

Quote:

Originally Posted by PaulCa13

Another option is to use the vacuum-assist module from Smallcar Performance:
http://www.smallcar.com/index.php?di...08e2b40e48eec7
It's a pretty inexpensive ($60 or so) item that bypasses the resistor and uses vacuum to somewhat improve shifting.

I used one for a couple of years before replacing it with a TCU add-on module. If anyone wants my old one, they can have it for $35 + shipping from the Seattle area.

You can reach me at paulca13@yahoo.com if you're interested.

smallcar kit=Bad idea

Keith

Naru · #9 04-19-2010, 08:09 AM

why smallcar kit is so bad?
seems not so bad idea.
what's wrong whit this system?

Bonestock · #10 04-19-2010, 09:36 AM

I made my own one and its adjustable for less than $10. I posted pics & p/n for anyone that was interested. Then of course, a pissing match ensued. Search my posts if you are interested in making one yourself. I think it was titled resistor mod ver2.0

Freeman · #11 04-19-2010, 10:56 AM

Smallcar anything is normally a bad idea. I say go for something like what bonestock has.

Naru · #12 04-19-2010, 11:32 AM

ok found the bonestock adjustable transistor mod.
seems realy easy to make.
i understand smallcar kit is not good. but why?
did the transmition can be damaged by this system?
why?
thanks!

kwren · #13 04-19-2010, 12:32 PM

Quote:

Originally Posted by Naru

ok found the bonestock adjustable transistor mod.
seems realy easy to make.
i understand smallcar kit is not good. but why?

can damage transmission...

did the transmission can be damaged by this system?

yes... can damage transmission...

why?
Makes things happen that are not supposed to happen that causes damage. I put one on my car and it ruined my transmission. Causes rougher shifting and that is not a good thing.

thanks!

Not sure about bonestock...

Keith

Trevor · #14 04-19-2010, 04:26 PM

SVX Transmission Line Pressure Control.

Line pressure is initially controlled via pulse width modulated, (PWM) electrical, normally closed, solenoid valve “A”. When open, this valve bleeds off pressure, rather than interrupts pressure, as a means of control. It provides precise control, but has only limited capacity. Therefore amplification is necessary, in order to achieve final control of the overall operative line pressure.

The adjusted pressure from solenoid “A” is applied as pilot control pressure, to a fully hydraulic pressure modifier valve. The pressure modifier valve, in turn controls the main pressure regulator valve. The result is a system of amplification, in two stages.

The use of a normally closed valve “A”, for electronic control of line pressure, renders the system fail safe. However maximum pressure must be limited and not allowed to runaway at high pump speeds. This is achieved by including the pilot valve, which sets the pressure, and the pressure modifier valve, within a feed back loop.

Solenoid valve “A” is controlled by means of a PWM signal, delivered by the transmission control unit, (TCU) via a direct circuit. This electrical signal comprises a series pulses, delivered at a fixed frequency of nominally 50 cycles per second. The length of the pulses, rather their frequency, controls fluid output from the valve.

The output pressure is therefore delivered in the form of waves at 50 CPS. However, due to the low volume delivered, the high frequency and the reciprocating mass involved in the pressure modifier valve, these waves have little effect. Furthermore, final control pressure from the pressure modifier valve, is smoothed by the pressure modifier accumulator, a device incorporated for this purpose, as is mentioned in section 3 within the Subaru manuals, under the heading Line Pressure Control .

The dropping resistor circuit.

It will be immediately apparent that the sudden on off pulse width modulated duty, to which normally closed solenoid valve “A” is subject, tends to cause what could be called a hammering of the valve seat, even though this is largely reduced/damped by the flow of the controlled fluid.

The dropping resistor introduces a second series of current pulses, applied in parallel with the control signal. These pulses are applied across the off cycles, so as to check the travel of the armature as it moves, thus reducing both shock and noise. These secondary parallel signals mean that in effect, during the closing/closed period, the voltage does not fall completely to zero.

This second series of pulses must be at a lesser level than the control signal, hence the dropping resistor. A resistor with a high current rating is required, which can not be mounted within the TCU enclosure.

Full voltage from the direct circuit operates the solenoid and quickly opens the valve. The low voltage dropping resistor circuit, holds in the solenoid and thus controls the point at which the valve is allowed to close. Therefore controlling the length of the low voltage pulse, sets the overall pulse length.

The full voltage direct circuit signal, comprises a very short fixed length pulse. This is immediately followed by an independent low voltage pulse, from the resistor circuit. The sum of the two provides the total pulse length delivered during each cycle.

It will be appreciated that increasing the resistance in the circuit, or opening the circuit by omitting the dropping resistor, will upset the normal pulse length, thus increasing the line pressure and making shifts more abrupt. Secondly, as an undesirable issue, shock loads applied to solenoid valve “A” are increased.

The resistor should measure between 9 and 15 ohms to be within specifications and is usually close to 12 ohms.

Trevor · #15 04-19-2010, 04:43 PM

Quote:

Originally Posted by kwren

I put one on my car and it ruined my transmission. Causes rougher shifting and that is not a good thing.

Keith

Keith,

You have made a definitive statement as above, specially emphasised in red. Can you be sure that the modification caused the ruin of the transmission and if so, exactly how and what happened? This is vital information of universal interest and requires confirmation.

I would have thought that because the modification operates only intermittently and is adjustable, there should be very limited cause for concern.