Automatic Transmission Fluid Cooler. ??

[Wayno]

Making progress, but don't know whether I want to connect it up myself tomorrow and put oil everywhere or take it to a transmission shop.

[nlowell]

Not much oil comes out since its not under a lot of pressure. With the lost oil and to compensate for the oil cooler and lines I added just under a 1/2 quart of WS using a fluid pump.

[Wayno]

So you say the aux cooler is after the oem heat exchanger in this configuration?

Originally Posted by nlowell

I had the car up in the air today doing some prep for Buttonwillow and took a picture of the oil cooler connection points. This is looking from the front towards the stock cooler.

[snidd111]

I remember there being talk of it going before because then the cooler/warmer would bring it to the right temp if it were too cold?

[Wayno]

Yeah I want to put mine before the heat exchanger, so it looks like I'd use the other line (towards the inside/front of the heat ex) than the one nlowell used (on the outside/rear of the heat ex)...

Originally Posted by nlowell

I cut the hose exiting the stock transmission cooler, inserted my custom reducer, ran the braided hose down the drivers side, across the crash beam, to the passenger fog area where the cooler is, then back the same way and back into the transmission using the 3/8 to 1/2 barbed adapter and the existing stock hose still connected to the transmission inlet.

[nlowell]

I put mine after the stock cooler. It was actually recommended, since I live in SD, that I remove the stock cooler completely. I decided to leave it in for the time being. If I add an oil pump later then I might remove the stock cooler/warmer and try to put the pump in its place.

The center line on the stock cooler is the IN line and the outer line is the OUT line back to the transmission.

[Wayno]

Yeah I also thought it would be better just to remove it and reduce as much restriction as possible as I live queensland where you still sweat in winter anyway.

[snidd111]

Someone recommended it's removal? Hadn't thought about that.

[Sithspawn]

Originally Posted by nlowell

I put mine after the stock cooler. It was actually recommended, since I live in SD, that I remove the stock cooler completely. I decided to leave it in for the time being. If I add an oil pump later then I might remove the stock cooler/warmer and try to put the pump in its place.

The center line on the stock cooler is the IN line and the outer line is the OUT line back to the transmission.

I wouldn't recommend removing the factory heat exchanger from the system. You want the fluid to come up to temperature since viscosity changes with temperature. You may have noticed that the car shifts differently when cold compared to when it is up to temp. That is because the valve body orifice sizes were specified by the engineer who designed them based on the viscosity of the fluid at operating temperature. If the fluid is too cold and the viscosity is higher than the design parameters, pressure will increase and flow will decrease. You need flow through the valve body to actuate the pistons inside the transmission to engage the clutch assemblies.

Modifying a valve body generally increases the orifice size of certain fluid circuits to increase flow and consequently increase hydraulic pressure to the pistons and increase the normal force in the clutch pack assemblies (which results in a higher friction force). Running the fluid too cold will mitigate the modifications done to your valve body and you will not be reaping the full advantages that you paid to have.

In regards to a pump. Our transmissions use a gerotor fluid pump that is similar in design to an engine oil pump. As such, it has no problem moving fluid at higher pressures. In fact, the pressure regulator valve inside the valve body supplies the high line pressure necessary for valve body and clutch assembly operation (pressure the pump is already producing) and shunts excess flow through the torque converter and the cooler circuit. Having a slightly higher cooler circuit pressure due to a little added restriction is not even going to phase that gerotor pump. The pressure regulator valve is designed to prioritize flow to the line pressure circuit so even if the cooler circuit is demanding a little more flow, the pressure regulator valve will only deliver it if there is enough head room to do so without dropping line pressure. Having a slightly reduced flow rate through the cooler circuit during the brief interval that the transmission is shifting is not the end of the world here and OEM's do it all the time. Any pickup truck with a factory equipped "tow package" has an auxiliary air/oil transmission cooler installed in line with the factory heat exchanger. Adding a transmission cooler on this car is really no different.

Originally Posted by Wayno

Yeah I also thought it would be better just to remove it and reduce as much restriction as possible as I live queensland where you still sweat in winter anyway.

Haha...lived in Cairns for a year and a half and I recall the "coldest" winter night requiring a windbreaker and jeans. Even still, it's no 75 - 95 degrees Celsius that the transmission fluid should be operating at.

[Wayno]

Thanks guys. This is pretty much the single most important thread for AT owners.

For future reference the recommended flow is:
1. From transmission to bottom of auxiliary oil cooler
2. From top of auxiliary oil cooler to center line of heat exchanger
3. From outside line of heat exchanger to transmission using factory hose.

Thanks to sithspawn for sharing all the data from testing and nlowell for the hose direction.

I really didn't like pushing the "quick mounting kit" plastic bits through the condenser and radiator. My poor car!

I bought 3m of hose and had to use the absolute shortest route including mounting the cooler on its side and when it came time to cut the loop at the heat exchanger to connect it up, I was really pushing it. Buy 5m hose to keep your options open.

[Wayno]

I'm confused. Am I supposed to perform the level adjustment with the engine RUNNING?! (In about one ft of space)


2) When shorting TC terminal circuit
(1) Short the data link connectors No. 13 and No. 4.
(2) Start the engine.
(3) Turn off all parts effecting an electrical load such as air conditioner, audio and lights.
(4) Operate the select lever in P  R  N  D  M  D  N  R  P to circulate ATF in the transmission.
(5) Operate between N D within 1.5 sec. for a continuous 6 sec. or more to switch to the oil amount
adjustment mode. When the vehicle enters into oil amount adjustment mode, the upshift/downshift permitted
indicator lamps [ ]/[ ] in the combination meter light up simultaneously for 2 sec. and turn off
with no relation to the range position.
(6) After changing to oil pressure adjustment mode, switch to the “P” range.
(7) Remove the short of data link connectors No. 13 and No. 4.
(8) Check the status of the upshift/downshift permitted indicator lamps [ ]/[ ].
CAUTION:
If only the [ ] indicator light is illuminated or both [ ] and [ ] are illuminated simultaneously, stop
performing procedures and leave the vehicle in a cool location. Start over and repeat procedures
from Step (1) after the ATF temperature decreases to a point where only the downshift permitted indicator
light [ ] when shifting to oil amount adjustment mode.
PM-00630
PM-00726
PM-75
Automatic Transmission Fluid
PERIODIC MAINTENANCE SERVICES
(9) Adjust the oil as soon as the proper temperature for oil amount adjustment is reached.
CAUTION:
Always be sure to adjust the ATF when at the proper temperature.
3) Remove the overflow plug and check the oil amount when at the proper temperature for oil amount inspection.
• The oil amount is proper when fluid flows out of the overflow tube and then the flow of the fluid is thin.
• If fluid does not flow out of the overflow tube, fill through the refill hole until fluid flows out of the overflow
tube. The oil amount is proper when the flow of the fluid is thin.
4) Install the overflow plug using a new gasket.
CAUTION:
Tighten the overflow plug with the ATF temperature at 43°C — 47°C (109.4°F — 116.6°F) (indicator
lamps [ ] and [ ] are illuminated simultaneously).
5) Perform final tightening of the refill plug using a new O-ring.
6) Install engine under cover No. 2.
7) Install engine under cover No. 1.
8) Lower the vehicle.
9) Turn the ignition to OFF.

[nlowell]

If you are just adding the oil cooler then really you just need to account for lost fluid plus the capacity of the cooler and lines.

My view is that you only need to go through that procedure if you are doing a fluid replacement. I had Infamous do the procedure when they installed my SSP valve body. They warmed the car to the set temperature but I don't think they kept the car running immediately after. If you do, the temperature will exceed the target range. If you take too long on the drain and overfill then you might need to restart the car to hit the target again. They did it all on a lift which is much easier.

If you want to just top off the "right" way - I think you would add a quart, warm up the ATF to the right temp (shifting slowly from P to D and back), turn off the car, open the drain and wait for the fluid drain to be a hair-thin. That's what I understood anyways. The car needs to be level when draining.

Sithspawn has way more knowledge then me and should verify though

[Wayno]

The last adjustment i did was with the car running and i just put the overflow plug in when the fluid changed from gushing to trickle. I ended up draining 2L overall due to emptying when the car wasn't running and filling about 2.5.

So yep if you don't have the car running and you pull the overflow plug you lose over a litre of fluid that has drained into the pan while not running, then it complains when you shift ranges.

[nlowell]

good to know, thanks!