Does anyone know what pressure the trans cooler lines run at. I am thinking about fabricating bigger lines out of stainless because I have two heavy duty coolers in front but I think the flow is to low with the std 5/16 lines. An engineer at work did some flow rates and if I use 1/2 inch lines I should get more than double the flow and with two high capacity coolers I think that would be better. At the moment temp are above 100f by 9am and towing my trailer has the trans running at a constant 190-205f.

 

Hey Frank,

Unfortunately, I don't have my E4OD books with me here. However, I think the normal peak pressure is around 100 PSI. If some one knows the cooler line pressure specs than please post them.

For safety factor, I would go to fittings and lines that are rated at minimum 300PSI since raw pressure is also compounded by that big rattling engine and bouncing around on the road.

I would like to go to a larger cooler line setup myself but haven't had the time so far.

 

I can get ss316 pressure fittings and tube rated at 600psi from work and we have the benders and I will get a new one way valve with a 1/2 inch id. My truck has had after market coolers since I owned it but as original did they have a flexible section between the cooler and the box to allow for movement or did they have solid lines the whole way.
Also what is the maximum safe working temp of these auto's.

 

600 PSI is more than enough.

The lines are generally hard from transmission to cooler at the front. The length is enough that it can flex/twist with the engine without causing fatigue. The frame of the truck does it lol

What I don't like about using rubber lines is they will eventually rot or leak at clamped connections. Metal will never weaken or get brittle over time from heat or oil exposure and will generally last the life of the vehicle.

The 93' GMC truck my dad had uses factory 3/8" steel tubing that is hard from the tranny to the cooler and that seems to hold up just fine (other than rusting out once). Usually what they will do is use rubber lines and hose clamps to plumb in an auxiliary cooler. All the trucks with extra coolers I've seen so far have soft lines at the front to make the extra connections. Nearly all the coolers I've seen have barbed hose fittings anyway so it usually can't be helped to use some rubber lines (my truck included).

Safe operating limit is 250F. Think of that as the high end of the yellow bar, not quite in the red, but really close to it. Its safe for short periods, but not for extended periods. Generally we try to aim for 150-160F while cruising but thats not always easy to do. Not sure how warm it is in your side of the island, but being summer will also limit you a bit.

Mine tends to run around 165 empty (warmer in very hot weather), but I never took readings while towing or pulling heavy up a hill. Your temperature could be better, but that is still well within the safe range. Some newer trucks run 210F right out of the box before attaching a trailer.

Something else I should mention, is there are differing views on weather to use the OEM cooler in the rad. I bypassed mine and it seems to work well but I am running 2 extra coolers. A new rad will cool very well, but if the engine runs hot or its an older rad with some solder bloom inside, it will run hotter. Some people say to bypass the rad cooler completely, while others say its required to keep the original, liquid heat exchange cooling.

The reason I mention this, is it might be worth a try to bypass it temporarily (assuming its not already) and keep a close eye on the trans temp to see what sort of changes there are.

 

The in rad cooler is already bypassed but my engine seems to run cool. I fitted a new thermostat because I thought it wasn't getting hot enough as it only runs at about 40-60 celcius (100-140f) which seems low to me even when towing in hot weather. For instance sunday I was towing close to 2000 kg trailer on a 36c day through rolling hills with some quite steep ones thrown in. Auto sat at around 200f all the way I had the air-con on full and engine didn't go above 75c (170f). I came out of overdrive as soon as I started in the real hilly bits and went to od on the long down hills. Also if I let my auto get over 210-220f I get the flashing od light and the code is excessive converter slip. This has happened twice and the converter lock works and the box was rebuilt less than10,000 km ago. I also heard that reading the trans temp from the oil pan was not accurate enough as my sensor is in the drain bung on the pan not up in the box somewhere.

 

Thermostats must be........
CAUTION:
The specified/required thermostat does not contain an internal bypass, since the bypass is located in the cylinder block. Whenever the thermostat is replaced, it is mandatory that only Motorcraft E5TZ-8575-C or Navistar 1807974C94 thermostat be installed.


Diesel engine coolant temperature at the top of the radiator where hose attaches after high rpm or under load condition for 20 minutes should be (195-237*F) 91-114*C nice time to have a temperature reading point and shoot tool.

Transmission upper limit is 250F for short term, 210-200F continuous........

Trans temp sender hole......... there is a test port on the drivers side ahead of the MLPS that members use for the temperature sender..... just do not block off the flow.

 

PLC7.3, your up late, or early depending on how you look at it.

I think Frank said earlier that he was able to order the correct thermostat. I wonder if the internal engine bypass could be open preventing full operating temperature.

Temperature difference I saw from the pan to the valve body was about 10F.

Frank, you might have mentioned this before, but remind me what size of cooler your are running?

 

Got the motorcraft thermostat. Luckily I found this forum just after I bought my truck so I research every part before I buy it because when you freight it this far it had better be right. I have never seen those sort of engine temps even on the hottest of days but have also not checked in the top tank. My sender is in the side of the block so maybe not getting totally accurate temps but OEM gauge has never got above "A" on "NORMAL" scale. If 200f continuous is ok for the auto then I am less worried but would be interesting to see if bigger lines makes a difference and since I can do it for free why not. Just wanted to make sure I wasn't going to hurt anything.

 

I have twin coolers not sure of sizes but they both have 3/8 inch hose tail inlets and outlets I think. They are running in parallel which is why I suspect bad flow with the small lines.

 

The oem guages are notoriously inaccurate. I have a mechanical guage on mine and when I drove it to alaska pulling a pretty good load it ran in the 195 to 205 on the long hills it would get 205 and the fan would come on. This was with ambient temps from 60 to 30 below on the trip,as soon as I dropped the load in wasilla and headed to fairbanks empty my guage would not get over 130 and idled lower to the extent the heater blew cool air but this was at 20 to 30 below temps. As soon as I got to fairbanks I got a thermostat at the int dealer and it would then idle at 180 and run at 190 heater would run you out. I'm betting you that the factory guage is off.

 

So I've got this other idea(dave's stop laughing).
If I fitted two threaded spigots into my trans oil pan could I plumb in an electric recirc pump with higher flow to an oversized cooler up front either with or without the OEM cooler lines aswell. It would take hot oil from one side of the pan and return cooler oil to the other side, My guess being the cooler oil would move towards the filter pick up rather than just straight back out the other side again. Thoughts? (again, stop laughing).

 

A few things to keep in mind, I have always been told that if the fluid moves too fast in the cooler, it will not have enough time to cool down.
If you turn the overdrive button off to hold the tranny in 3rd while climming a hill or it downshifts on it's own, the torque convertor should stay locked up(0 slippage). The torque convertor is where most of the heat is comming from in an auto tranny. I don't understand why you get the excessive converter slip when the convertor should be locked. Did you put a new convertor in with the tranny rebuild? are you sure the convertor is not slipping?
Liquid to liquid heat exchangers ( like the factory trans cooler in the radiator)are far more efficient than air to liquid exchangers. I run the my tranny fluid in the factory cooler in the radiator then to another cooler. This ensures the fluid is up to temp quick to make sure the fluid lubricates everything and it will always be cooler than the engine temp.

 

The po of my rig installed a similar setup on the T19 manual tranny in mine, it even has it's own electric fan.
I've never had a guage so I can't tell you how much difference it made, it only sees light duty now so I have disabled it so the pump and fan no longer runs but did not remove it so I can hook it back up if I want.

 

Actually I think I've seen kits like that before but they usually come with an oversize aluminum pan that is ready drilled and tapped for the fittings. Nothing crazy about that at all. Some have an electric fan like starmilt describes although I can't imagine why the T19 would ever need one

 

the pump system to the pan is a waste of time and money it will have zero effect
first the trans temp should be kept below 200 degrees f. if at all possible 250 is beyond factory overtemp in fact 240 degrees is the overtemp threshold
it is also close to where the red dye in atf will turn clear due to temperature breakdown
the cooler lines recieve the fluid from the torque converter and after cooling go to the rear lube circuit then to the pan
the reason you have excessive converter slippage codes is because when the transmission gets too hot the lube circuit pressure falls off and there isnt enough pressure to hold the converter clutch applied and slippage results
and any automatic that is towing needs the in radiator cooler to remove heat through liquid transfer
air only coolers cannot achieve a radical transfer of heat from oil
if air only would work ford would have saved money by not using the radiator cooler
it was tried in 99 and 2000 with no radiator cooler which spawned a tsb to install a radiator cooler for towing
i prefer installing the gauge sender in the front transmission outlet cooler line so that the actual trans temp is read before cooling is done
in the pan or in the pressure test port is unreliable because both get the fluid after cooling and with massive coolers will give a false sense of trans temp
you also need to istall a pump modification kit from superior transmission it seperates the lube circuit and converter apply circuits to correct pressure loss to the converter
i use it on every E4OD overhaul , except the bushing they supply i prefer a factory style bronze bushing
the cooler is also low pressure there is no way a radiator cooler could withstand a 100 psi pressure
good luck and for the record late model production vehicles have 1/2 inch cooler lines
the larger the lines and coolers the longer the fluid remains in the cooler by reducing the speed due to increased volume
its that py square formula