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  #16  
Old 02-03-2010, 02:29 PM
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Re: trans question

I am not really sure if mine is doing the same thing. If I am driving at say 45 to 50 MPh on the high way and I depress the gas even slightly it seems to down shift and the RPM goes up about 500 RPMs and then settles back down . like there is no lock up in the converter .
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  #17  
Old 02-03-2010, 06:06 PM
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Re: trans question

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Originally Posted by Conn SVX View Post
I am not really sure if mine is doing the same thing. If I am driving at say 45 to 50 MPh on the high way and I depress the gas even slightly it seems to down shift and the RPM goes up about 500 RPMs and then settles back down . like there is no lock up in the converter .
This sounds a bit more like the TPS to me. My car could never choose between 3&4 while cruising, but did fine when I leaned on it a bit more. 1-2 shifts were also really hard. I knocked off $2k when I bought mine because it felt like a blown trans. That little sensor got it running like new and I haven't had any trouble since.

I know I'm no expert, so I won't muddy up the thread any more, but I wonder how many SVXs were scrapped over misdiagnosing this problem.
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  #18  
Old 02-03-2010, 06:49 PM
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Re: trans question

ROb is going to bring over his MODUS this weekend and we are going to graph the TPS.
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  #19  
Old 02-03-2010, 08:03 PM
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Re: trans question

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Originally Posted by Bonestock View Post
ROb is going to bring over his MODUS this weekend and we are going to graph the TPS.
You are looking for intermittent connection with the included conductive plastic resistive element. This does not necessarily require "graphing" the resistance during a sweep of the control shaft. A simple resistance test will usually disclose a problem.

However, the speed of response of the ohm meter is obviously important, so that a multi meter with a bar graph scale is preferable, or better still an oscilloscope. Alternatively there is a way of testing, involving audio devices.

Cheers Trevor.
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  #20  
Old 02-03-2010, 09:09 PM
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Re: trans question

I understand where you are coming from Trevor but are you familiar with the Modos? Most dealerships dont even have one of these amazing computers. Its a bit nicer than my "red brick" from a million yrs ago! LOL And I stand corrected, Rob was very quick to point out that he now has a Verus. I guess thats better, I never could keep up with all his "toys". I guess its a matter of trying to check and rule out everything before I bite the bullet and find that I am going to need a rebuild. Just my luck apparently.

So what did you think about the comment I made earlier about the shifts once the resistor was unplugged? I was thinking maybe just maybe I discovered a problem before much damage or wear occurred. We will see but I dont hold much faith.
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  #21  
Old 02-03-2010, 10:17 PM
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Re: trans question

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Originally Posted by Bonestock View Post
Well I tested it in 3rd this morning and sure enough it "hung" between gears. On my way home today I unplugged the resistor and it didn't hang at all. Shifted quite nicely, actually.

So, now what?
Well to me, it looks like the line pressure is low. Disconnecting the resistor, gives full throttle pressure. Low pressure can be caused by the screen in the pan, being restricted, or from a lot of wear..
You could get the line pressure checked, but if it is low, there is not much you can do, other than, get one of Svxfiles resistors that will allow a bit more line pressure,and drive it in 3rd below 40mph.

Harvey.
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  #22  
Old 02-04-2010, 04:59 AM
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Re: trans question

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Originally Posted by Bonestock View Post
I understand where you are coming from Trevor but are you familiar with the Modos? Most dealerships dont even have one of these amazing computers. Its a bit nicer than my "red brick" from a million yrs ago! LOL And I stand corrected, Rob was very quick to point out that he now has a Verus. I guess thats better, I never could keep up with all his "toys". I guess its a matter of trying to check and rule out everything before I bite the bullet and find that I am going to need a rebuild. Just my luck apparently.

So what did you think about the comment I made earlier about the shifts once the resistor was unplugged? I was thinking maybe just maybe I discovered a problem before much damage or wear occurred. We will see but I dont hold much faith.
I know nothing of “Modos” nor does Google.
As long as it performs the functions as I have mentioned all should be well.

The thread has become rather confused and I missed your post on the previous page.

Some info on the resistor circuit ---

Solenoid valve “A” is subject sudden on off pulse width modulated duty cycle at 50 CPS. This tends to cause what could be called a hammering of the valve seat, even though this is largely damped by the controlled fluid flow.

The dropping resistor circuit 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 reaches the closed position, thus reducing both shock and noise. This secondary parallel signal in effect, mean that during the closing period the voltage does not fall completely to zero, so as to reduce a closing shock.

This second series of pulses basically comprises an inversion of the main control signal, delivered at a reduced voltage, as a result of the in line resistor. A resistor with a high current rating is required, therefore it can not be mounted within the TCU enclosure.

It will be appreciated that increasing the resistance in the circuit, or opening the circuit by omitting the dropping resistor, has two outcomes. Firstly the voltage during the closed time becomes zero, thus increasing the line pressure and making shifts more abrupt. Secondly, as an undesirable issue, shock loads applied to the valve are increased.

N.B. Disconnecting the resistor does not result in full line pressure. Line pressure will remain controlled by the ECU, but at an abnormal increased level.

If the line pressure is low, it will be obvious to you that there is much you can do about it. You can replace solenoid valve "A" if the seat is leaking, and check the filter screen fairly easily. Very worthwhile before rushing into something major.

Best of luck with it, Trevor.
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Last edited by Trevor; 02-04-2010 at 01:56 PM. Reason: Item added.
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  #23  
Old 02-04-2010, 05:56 AM
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Re: trans question

http://buy1.snapon.com/products/diag...IN&dir=catalog
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  #24  
Old 02-06-2010, 12:37 AM
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Re: trans question

Its fixed. Turns out the external filter was pretty old and not happy! Once I took care of that I performed the power mode mod. Still not as good as I thought it would be. Gonna get a performance valvebody next.
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  #25  
Old 02-06-2010, 02:22 AM
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Re: trans question

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Originally Posted by Bonestock View Post
Its fixed. Turns out the external filter was pretty old and not happy! Once I took care of that I performed the power mode mod. Still not as good as I thought it would be. Gonna get a performance valvebody next.
You were wrongly told, --- “but if it is low, there is not much you can do,”

and properly advised. --- “If the line pressure is low, it will be obvious to you that there is much you can do about it.

For years and for good reason, I have I have disagreed with the fitting of an external filter. The reason has been illustrated here.

Do not continue with the “power mode”, by changing the resistor.

Test the line pressure again, with the resistor circuit as per specifications. There should be 65 - 80 psi at idle (500 - 700 rpm.), at normal engine operating temperature, with the selector in all positions except reverse, when there should be 85 - 100 psi.

If it the pressure is below specification, replace the “A” solenoid valve. Cheap and easy.
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Last edited by Trevor; 02-06-2010 at 02:51 AM. Reason: Typo
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  #26  
Old 02-06-2010, 02:31 AM
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Re: trans question

Quote:
Originally Posted by Bonestock View Post
Its fixed. Turns out the external filter was pretty old and not happy! Once I took care of that I performed the power mode mod. Still not as good as I thought it would be. Gonna get a performance valvebody next.
Sounds good, but I doubt that is the cause of your trouble.
That filter is on the torque converter cooler circuit. It would not alter the line pressure, if it was blocked, only destroy the planetary gears.

Harvey.
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  #27  
Old 02-06-2010, 09:27 AM
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Re: trans question

Well I dont know what to tell you Harvey. All I did was get a new one and drain and fill the fluid.

Trevor, you advise against using Subaru's filter kit? Sorry, I am going with the guys that built the car on this one. Its not a problem with the filter, its basic maintenance that was an issue. This car has been setting since at least Aug of last yr.
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  #28  
Old 02-06-2010, 02:35 PM
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Re: trans question

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Originally Posted by Bonestock View Post
Well I dont know what to tell you Harvey. All I did was get a new one and drain and fill the fluid.

Trevor, you advise against using Subaru's filter kit? Sorry, I am going with the guys that built the car on this one. Its not a problem with the filter, its basic maintenance that was an issue. This car has been setting since at least Aug of last yr.
Subarus are very common in thus part of the world. Many transmission specialists remove external filters as a matter of course, when doing a rebuild, because blocked filters have so often been the cause of major problems. They also do so when fitting an auxiliary cooler to taxis etc.

When I had my cooler fitted, I also asked for a filter as was advised within this site. I was told not to fit one, even though this would have provided the shop with more money for the job. I accepted the advice.
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  #29  
Old 02-06-2010, 02:47 PM
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Re: trans question

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Originally Posted by oab_au View Post
Sounds good, but I doubt that is the cause of your trouble.
That filter is on the torque converter cooler circuit. It would not alter the line pressure, if it was blocked, only destroy the planetary gears.

Harvey.
The cunning idea was a quick post to hide mine and save embarrassment. The final result is the embarrassment of three wrongs in a row.

The cooler circuit is not confined to the torque convertor. It has been stated here many times that a cooler not fitted adjacent to, or involving the radiator, will result in slow heating of the transmission fluid and an inconvenient delay before lock up.

Lock up is controlled by the TCU and initiated via n/c solenoid “B”. The TCU receives a temperature signal from a sensor on the valve body, in the lower part of the main transmission assembly. No more needs to be said.

If the filter is confined to the torque converter circuit, how could it possibly be that, “if it was blocked, only destroy the planetary gears."
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  #30  
Old 02-06-2010, 03:29 PM
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Re: trans question

Trevor I appreciate the input. However, I think the guys at Subaru are a bit mote familiar with their own product than some bloke at your local menders.
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