Heating the transmission with engine coolant

[renault_megane_dci]

The issue is to transform hot water in hot oil on a gearbox that didn't started life with an oil cooler ...

Even then, the control of the heat and additionnal way of getting rid of it when you need to avoid it calls for quite some work ...

I would try to fit an oil cooler first then insulate the gearbox.

Bringing extra heat is step 3 as far as investment goes ...

[wrw166]

just use synthetic transmission oil. It's pee thin

[DonR]

Here's an idea if your Trans Drain plug is large enough.

Drill two holes in the drain plug for a small flexible copper tube. Make a loop in the tube, run the ends through the two holes. Check for clearances inside the transmission. Braze the tubing to the drain plug. Almost looks like a screw in block heater at this point.

Tee into the heater core hose to feed the transmission heater. This should bypass the thermostat. Have the return line go to a low pressure side tee.

Get fittings to adapt the rubber hose to the copper lines.

You should be able to use an electric solenoid valve to turn the flow on & off.

Control can be manual unless you have the smarts to read coolant temps and trans fluid temps and have a home made computer turn the valve on & off.

[Daox]

Originally Posted by wrw166

just use synthetic transmission oil. It's pee thin

I have poured synthetic 75W-90 into a transmission in the middle of winter, and it is nowhere near that thin.

Here's an idea if your Trans Drain plug is large enough.

I like that idea DonR. I'm not sure there is that much clearance though. We shall see when I finally crack a trans open.

[Cobb]

12 pages and the rubber hasnt hit the road yet???

How about take my idea and use the heater either stick on, magnet, or dip stick for test of concept to see if there is any benefit before finding a way to use heat from the engine.

Now thats the nice thing about an automatic with a trans cooler inside the radiator. This allows it to get to operating temp faster for performance and keep it cool.

The bad side is if you over heat the car you can damage the tranny or a taxed cooling system can over heat from a hard working transmission.

[Daox]

As stated in the first post, the Tercel isn't on the road yet. I'll get there, I just wanted to discuss and evolve my idea.

Testing will definitely be done on how fast the trans heats up by itself.

[Cobb]

My bad, I see that was back in August.

Be interesting it you see anything or if its measurable considering rolling resistances, air resistances, etc. When its cold enough to effect shifting a manual its cold enough that even grill blocking and ethanol winterized fuel has an already significant effect on mpg not counting heater usage and electrical draw for that and replenishing the starting battery on the alt.

[renault_megane_dci]

Originally Posted by DonR

Here's an idea if your Trans Drain plug is large enough.

Drill two holes in the drain plug for a small flexible copper tube. Make a loop in the tube, run the ends through the two holes. Check for clearances inside the transmission

The end shape of the tube has to be able to go through the hole and to be spinned on.

After considering it with a lot of enthusiasm, I think using water to heat up a manual gearbox is a dead end ...

You can't turn it off easily and it uses a bulky setup.

Spinning on a thermoplunger in the drain plug to heat the gearbox as you heat the engine on grid seems like much less hassle ...

[Xist]

Originally Posted by wrw166

just use synthetic transmission oil. It's pee thin

Not if you have been drinking conventional transmission oil.

[Cobb]

Ive fooled with some amsoil synchromesh on the clearance isle. Its in a clear bottle and its red in color. Splashes around at room temperature like water. The same thing in the orange bottle was more like syrup.