Volkswagen Passat Forum banner

21 - 30 of 30 Posts

·
Registered
Joined
·
23 Posts
Discussion Starter #21 (Edited)
EDS1( N215) is used for line pressure control only, and operates from 0 to 0.8 amps. When the solenoid is "OFF" (0 amps), pressure is high. EDS 1 pressure is "Lowered" as the solenoid is modulated by the control unit.
EDS 2, EDS 3, and EDS 4 Solenoids are also pulse modulated but are exactly the opposite of EDS 1 Solenoid. When these solenoids are "ON" oil pressure in the hydraulic circuit is high, and when they are "OFF" pressure in the hydraulic circuit is low.
EDS 4 Solenoid is used for Torque Converter Clutch apply and release only, and depends on throttle position and vehicle speed as to its application.
Line pressure is the priority oil and converter charge is secondary. So what happens when the cooler pressure drops is the TCU restoring the line pressure after 2-3 and 3-4 shifts by lowering the amperage to N215 to 0.096 A. The question is if it is normal for that pressure dip to last 2-3 seconds. The cooler pressure also is lowered to 5 PSI when oil is hot in D and R at a stand still. In D, if you you stay long enough at a stoplight, the cooler pressure is raised because the N215 stays somewhere above 0.250 A, but only to about 10-15 PSI. So I try to keep it in N at stoplights and the pressure stays at 20-25 PSI and N 215 stays at 0.696 A. Obs.: Flow/pressure in N seems to be higher than when the trans is in P so, if you also try to cool the trans, keep it in N.
As far as warm-up and cooling goes, I am happy with the result except for how the 4 port thermostat allows too much oil to flow through the cooler before reaching normal operating temperature. I will replace it with my costum build thermostat that has 3 ports and is designed to restrict cooler flow before oil reaches about 70*C and shut the warm-up path completely once the fluid reaches 80*C. The only other issue I have is cooling in city traffic. Since I did not have enough space to fit a fan on the Setrab, I was hoping that the viscous coolant fan and the A/C fan will move enough air to also cool the trans but it doesn't. Trans temp go up to 88-90*C and lower to 80-82*C only when the car is moving 50-60 Km/H for a few minutes. I will shroud the Setrab to the A/C condenser so the air flow through the trans cooler is raised when the fans are on. Also the viscous fan does not seem to get stiffer as the engine gets hotter so I will check that too.

I also forgot to say that I modified the PWR Steering cooling. I am using the former trans cooler in the radiator for that now. I have also a Magnom magnetic filter before the cooler and a Magnefine 3/8"magnetic and paper filter between the cooler and PWR steering reeservoir. Flushed and than filled and bled the steering system using almost 2 L of new OEM fluid so now it is "green and clean" ( for those that don't know what I say watch this
)
 

Attachments

·
Registered
Joined
·
9,544 Posts
View attachment 100117
Pressure sensor on the external thermostat on the cooling lines.
The only thing missing in the above picture is the Magnom thermostat which is located on the cooling outline before the remote spin-on filter.
That pressure sensor is only reading the pressure generated by the flow through the resistance in the external circuit,
the pressure would vary with changes to flow and/or temp.
It is not related to the various pressures within the transmission.
 

·
Registered
Joined
·
1,949 Posts
For what it’s worth in the name of meaningfully contributing to this conversation but I installed a large trans cooler and TransGo kit on my AWM-5HP19.

Observed that the trans fluid temp. Never exceeds 81C even in stop-go Atlanta traffic when outside temp is 37-38C (100F)

Normal highway driving, the trans fluid is around 75-76C. Yet to see how it performs in winter temperatures here (40-50F)

I installed the TransGo kit after I saw a BMW X5 guy on YouTube (50sKid) who said it eliminates the engine/trans vibration particularly at red light traffic stops with the gear on D. I thought it worked fine initially but gradually it went back to what it was before. Still vibrating.







Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
23 Posts
Discussion Starter #25
100434

Tom,
Unfortunately only one of the three things you said is true: pressure changes with temperature. Pressure in the cooling/lubrication system is generated by the fluid volume trying to feed the lubrication. There is barely any resistance in the cooling circuit except the coolers back pressures which are minimal. That volume of the fluid depends very much on the pressure loses within the valve body and the rest of the transmission.
 

·
Registered
Joined
·
23 Posts
Discussion Starter #26
Is that cooler in series with the factory one from the radiator? No external thermostat?
 

·
Registered
Joined
·
1,949 Posts
Is that cooler in series with the factory one from the radiator? No external thermostat?
I bypassed the factory cooler and hooked the cooler up directly to the hoses coming from the transmission.

No external thermostat.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
9,544 Posts
Tom,
Unfortunately only one of the three things you said is true: pressure changes with temperature. Pressure in the cooling/lubrication system is generated by the fluid volume trying to feed the lubrication. There is barely any resistance in the cooling circuit except the coolers back pressures which are minimal. That volume of the fluid depends very much on the pressure loses within the valve body and the rest of the transmission.
I am not going to argue this with you, and I probably should have been more specific about the resistance in the return and included the lubrication system.

Regarding heating the ATF through the engine cooling system.
It doesn't work.
During warm up, the ATF temp rises much faster than the coolant around the OEM ATF cooler.
The only time the coolant around the ATF cooler would be above the normal ATF temp, would be in extreme heat conditions which
would also cause the ATF to be hotter. It is unlikely that heat would ever transfer from coolant to ATF.
 

·
Registered
Joined
·
23 Posts
Discussion Starter #29 (Edited)
Tom. There is no need to argue, just read the Sonnax article attached earlier and look at the diagrams I attached. You can also read this Hydraulics Fundamentals Part VI: Converter Limit Valves and the 5 previous articles to understand better how wear in different valves can affect the system as a whole. Sonnax sells a tool to check cooler flow and detect flow-related transmission problems during vehicle road tests or on a dynamometer SonnaFlow® Kit - FM-01KA

Also I am sorry if I did not make myself clear about what I am using to warm-up the trans. I posted earlier that the cold return from the external thermostat goes through an Audi A8 trans cooler that has warm coolant flowing through it coming back from the cabin heater. And that makes a huge difference on how fast it gets warmed up and also on not allowing the trans fluid to cool down too much at higher speed.
You are absolutely correct about the OEM ATF cooler and I talked about why I gave up on using it and switched it to power steering cooling.

I have a 2010 Audi Avant 3.0 TDI Quattro that is awaiting the same modifications to the trans cooling, warm-up and all the other goodies. OEM trans cooler is similar to the Passat and there is also a coolant return sensor that shows how cold the radiator stays until the thermostat opens. So I know that OEM trans cooler does nothing for warm-up. Check my posts in this thread ZF 6HP19A tiptronic gearbox (A6 3.0 TDI Quattro) - Page 38
 

·
Registered
Joined
·
23 Posts
Discussion Starter #30 (Edited)
Bad news. I received the Sonnax Vacuum test kit and tested the main pressure regulator valve on one of the valve body that I have dismantled. It is supposed to be reamed to an oversize valve if it fails to hold the recommended minimum -18 in-Hg out of -25 in-Hg. This one holds less than -5 in-Hg, yet there are no signs of wear on the anodized valve. So using the TransGo shift kit on this particular valve body would be useless. There is too much wear than cannot be picked up by the extra seal this shift kit has. This valve body comes out of a transmission that had the D/G drum broken.
Most likely the valve body that is in the car right now has wear too but we will see soon.
 
21 - 30 of 30 Posts
Top