Transmission heating and cooling
 

First rule of externally heating your transmission is you can not add heat to the transmission in an uncontrolled manor. You will fry it. The #1 killer of transmissions by far is heat.

My current transmission is the GM TH700R4, its current cooler setup does what its name implies.
It cools the transmission, too much at times in the winter.
Also being a light duty transmission it has proven to me that it can not pump enough fluid through its cooler circuit to properly cool its self during the hot summer. I am going to fix all that in the next revision.

Any one up north or on the east coast is thinking what I was thinking before I moved to New Mexico and that is they don't really even have winter.
Well so far every year has produced numerous winter nights at, near or below 0'F. Some years more than others. The coldest year so far has had a full week of -10'F nights in a row with a -16'F night that froze almost everyones pipes.

I am going to harness 2 sources of heat for the transmission, internal and external. Keep the internal heat in side the transmission when its cold out and add external heat when the transmission is in need of warm up.

When it gets near freezing my temperature gauge doesn't move past the lowest mark, 100'F. This should fix that.

External transmission heating will be accomplished 2 ways. With engine heat and external vehicle power.

Trapping internal heat will be accomplished by installing a thermostatic valve on the transmissions existing cooler circuit. When the transmission fluid coming out of the discharge port is below 120'F it will all be looped through the hot side of the valve to a plate heat exchanger and right back into the transmission.
My suburban has a "transmission cooler" on the hot side of the radiator. So it is useless for warming up the transmission at the same time the engine is warming. This set up will only give up heat to the transmission only once the thermostat starts to open, as the engine reaches operating temperature. On very cold days the thermostat doesn't even open or doesn't stay open.

On the flip side New Mexico gets well above 100'F every year.
The thermostatic valve will have a cooling side in addition to the hot side of the valve. Once the transmission heats up above 120'F the thermostatic valve will start to activate and the cold side of the valve will start to include more fluid from the front mount coolers (already installed) as it closes off the hot side of the valve and its hot fluid.
The thermostatic valve will function to maintain fluid temperature between 120'F and 140'F.

Heating with external power will be done by direct heating of the fluid with a repurposed engine block heater. I have found the stick on heaters to be almost useless.
I will use a 400 watt Kat's engine block heater. The one I found uses a 3/4NPT connection. So you could use this block heater almost any where.
http://ecomodder.com/forum/attachmen...1&d=1435897722
I need to test this to make sure it wont scorch the fluid.

To add heat from the engine coolant to the transmission I am going to put a plate heat exchanger on the hot side of the thermostatic valve.
I impulse bought a 30 plate heat exchanger off ebay just before typing all this.
Its 316SS, pressure rated for 445psi and temperature rated for 300'F. Which should be sufficient. It has male 3/4NPT ports on all 4 corners. The 3/4NPT ports are perfect for hooking up coolant, but I will weld a 304SS 1/2'' pipe coupler cut in half on to the ports I am going to use for hooking up transmission fluid.

The vessel that I am going to use to house and attach all this new equipment is a Moroso aluminum transmission pan. The Moroso has 2 drain plugs. Why they put 2 drain plugs I do not know but I can reuse them.
http://ecomodder.com/forum/attachmen...1&d=1435898489
The pan is going to be painted black to increase infer red emissivity.

That little problem I mentioned in the start of the post where the transmission doesn't pump enough fluid to cool its self will be fixed by adding an external 3.2GMP seaflo oil pump to a stand alone cooler. Controlled by 150'F Reznor fenwal thermoswitch and manual switch.
This thermoswitch will also disable the external powered fluid heater.
I already have the horizontal mount auxiliary trans cooler with fan installed, just need to get a good supply of hot fluid to it.

Kat's part number: 11409, $40
These Reznor fenwal switches are cheap on ebay right now. $10 each
30 plate heat exchanger $82.
Seaflo oil transfer pump $80 (only for cooling)
Thermostatic valve $?? (I have not found the one I want to use)

Very interesting project. :)

I'd be a bit worried about that 400W heater scorching the trans fluid too, perhaps you can use the pump to circulate things while plugged in? I'd imagine that would alleviate the issue.

Auto trans have pretty huge cold start penalties, this should really help you out.

I'm looking forward to more pics and progress! :thumbup:

If the block heater puts to much heat on the transmission fluid and scorches it then I can put a power diode in line with the AC power going to the block heater and just feed it half wave rectified DC effectively cutting its power in half.
I really don't think 200w over that much surface area will cook the fluid.
So I know one way or another I can get the block heater to not cook transmission fluid.
All I have to do is find some one who can weld aluminum. Fluid tight joints on aluminum is about the only kind of welding I don't do.

Bulkhead fittings?

I need to do something like this to my transmissions even though they're manuals. When it gets around thirty below they sure get hard to shift.

Instead of using an engine block heater that is supposed to heat water why not get a dedicated oil heater. I think they usually have a bigger surface area cast onto the heating element. That way the heat spreads out more. 400W doesn't sound like much to me. I use a 1,600W heater for the water on my Golf. I'm considering a 2,000W heater for the astro.

Interesting project. Curious how the aggressive heat cycling impacts the hydraulic oil longevity.

I have used one hydraulic oil filter in a piece of equipment I worked on years ago. It used a 3 phase 4 wire 6,600 watt heating element, it was rather large and had quite a bit of surface area.

I am using the 3/4'' pipe thread heater assuming that's all I can get to fit in the transmission pan. I have ordered both 1''NPT and 3/4''NPT weld in aluminum bungs.
If I can use the 1 inch bungs then I can use hot water heater elements and transfer 600 watts worth of heat to the transmission fluid over a much greater surface area. Using hot water heater elements they will be ran at a fraction of their normal operating wattage.
If I were to use a hot water heater element I would run a 2400 watt 240 volt heater at half voltage giving me 600w watts of heat, or a 1200 watt 120 volt heater on half wave power, again giving me 600 watts.

I picked the 3/4''NPT heater because I knew if I didn't use it in the transmission I can always put it in the differential cover.

Looks like the dedicated oil heaters are only 200W. I guess it's to advoid scorching.

http://www.jegs.com/images/photos/500/555/555-23675.gif

JEGS Oil Pan/Sump Immersion Heater - Free Shipping on All Orders @ JEGS

200w just seems a little slow.
I can try to install a 2400w 240v hot water heating element, run it at half voltage and supply it half wave rectified power. Cutting its output down to about 300 watts.
Then fit the pan with a thermostat and thermal fuse for backup.

I had a 200W pad heater under the oil pan once. I couldn't tell if it made any difference. I think once the oil got pumped up into the cold engine it was cold again. The nice thing about my 1,600W water heater is that it circulates that water through the engine as it heats it. I wonder if you could circulate the transmission fluid through a heater. Or maybe just cover the entire transmission in 200W pad heaters.

I work for an electric utility. The 2008 and newer small bucket trucks have a 12 volt oil heater in the hydraulic oil reservoir. The trucks also have a thermostat in the tank so my drivers just leave the switch on year round. The heater has a 30 amp breaker on the circuit. The heater looks like the one in post 9.

I could put a bunch of 200 watt heats all over it but the transmission still needs to be able to radiate and conduct heat away from the case when its 115'F in the summer.
I am thinking if I leave the transmission fluid hot enough for long enough it will convex and radiate heat at least up into the valve body. Not really sure how well the pan heater will work, that is why I am going to test it and still add a 55,000BTU/hr 30 plate heat exchanger to warm the transmission fluid with engine coolant, just in case.

The suburban is getting a new version of my 240 volt powered coolant heater. The 5500 watt (18,000BTU/hr) version is just waiting for me to make an improved lighter weight more stainless steel housing as opposed to 15 pounds of steel water pipe I was going to use. Sounds like a lot but the coolant has always heated the engine oil and will now have to also heat the transmission, fuel and the rear compartment maybe more.

Actually I did make a hot water heater element oil pan once, got it all finished then I realized I was trying to put a non-turbo oil pan on a turbo block (the rear main bearing cap is bigger on the turbo block) and it would not fit, not even close.
So that was a waste of time.
I could do this again.
Obviously I would not run the in sump oil heater any where near 1200 watts.

Pre heat control
 

How about running a 150° -15f. fan control switch NC (normally closed) just above the heating element~ 1" (get it as close as the threads will alow). Like this (°.) one above the other . This would cycle As the viscosity is very high when cold. Heated fluid would trip the switch alowing the elements to cool .I'm guessing that in a thick fluid ~1"above the element @150would be @180+- down at element surface, experiments are needed to un gess this part.The residual heat would convect cooling itself and controlling sender turning the power back on. For higher viscosity diff fluid a lower temp. setting may be needed to keep from burning the fluid.
adjustable 160°-240°f -15° normally closed switch
This switch is active(closed) up to the set point then opens the circuit cooling 15°f reestablishing connection, and backand forth.
-----220°f sounds kinda hot
http://www.jascoautomotive.com/jpspe...heat_chart.PNG
I used a similar chart to explain why a Trans. Cooler was "nesasary " when adding a hitch to a car ,van,or non-towing package vehicle back when I worked @U-haul as a Hitch Pro.
Sold 1 cooler out of 60 hitches ~250 hitches a year.
GM was having a lot of auto trans. Over heat failure problems when they bumped the Corvette up to a 210°f thermostat. Back in the early 2000s
-----
Would running 2 heaters in series cut the heat output in hafe?
If so ,then 2 600w heaters with more surface aera would put out 300w ea. Reducing the chances of burning the atf resulting needing a transmission service @$$$ or failure @$$$$ synthetic atf is spendy. Rebuilding is more than any possible FE savings.

Gumby stay flexible.

This sounds like a good solution for tsb 07-01-89And would alow more time in OD

I would only use the transmission heater on cold days when not towing a trailer.

600 watt heaters are too small, even two 600 watt heaters both running at a total of 300 watts could still be too hot. I am thinking more along the lines of using a 1500 watt heater and running it at 200 to 400 watts.

Any progress report on this Oil Pan?

Not a lot, I picked up some NO 110°F switches to use on this project and my home hot water recirculation project.
I also scored some new longer 1500w heating elements I plan to use specifically for oil warming.
Then I was also considering using that plate heat exchanger as an oil to coolant heat exchanger on my big block Chevy 8L build and not using it on the transmission.