Heating the transmission with engine coolant

[darcane]

With an automatic, this would be easy. So easy that it's already done in most cars.

Manual is a little trickier. That thick oil will only slowly warm up, and you will have to wait for the coolant to get warm before it starts heating it up anyways. Trying to run coolant lines back to your tranny to warm it up seems like a Rube Goldberg device that will likely end in leaks and no measurable gains with your short commute.

Replace the dyno squeezings with a decent synthetic oil and call it good. Add electric heating if you are running it elsewhere (coolant, engine oil).

[darcane]

Oh, and what temps to you typically see in the winter?

[jakobnev]

You could try thinning that oil with ATF. (Even switching to pure ATF if the manual specifies it for cold ambient temps)

You could also try an under tray keeping the tranny out of thr wind.

[markweatherill]

I doubt there is much to be gained from warm vs cold manual gearbox oil.
The main 'losses' are coming from the gears themselves. A synthetic oil with good cold performance may benefit more, or some additive like Molyslip.

In fact on a FWD car, I might guess that the gearbox casing will transmit a certain amount of heat from the engine anyway, albeit slowly.

[darcane]

Originally Posted by markweatherill

I doubt there is much to be gained from warm vs cold manual gearbox oil.
The main 'losses' are coming from the gears themselves. A synthetic oil with good cold performance may benefit more, or some additive like Molyslip.

In fact on a FWD car, I might guess that the gearbox casing will transmit a certain amount of heat from the engine anyway, albeit slowly.

Depends on how cold and what oil is used. That was why I asked about his winter temps. Conventional gear lube gets to the consistency of roofing tar at -40 degrees.

[Daox]

I have no idea what my temps actually are. Throwing a sensor on the trans would definitely be step one. I found some info online from truck guys measuring trans temps, but it really wasn't all that useful. They didn't measure warm up times or anything like that, and they're mostly automatics which I assume heat up much faster and farther than a manual trans.

[oil pan 4]

2x post

[oil pan 4]

I measured it once. My 5 speed transmission in a V6 Camaro would warm up to about 140'F after a lot of driving, this was also during warmer weather.
I have no idea how long it took to warm up, since there is no cooler or circulation I bet it took a long time to get up to that temp.
I also think a FWD car will warm a little better.

[aerohead]

At automotive refinishing supply houses they sell viscosimeters which could be used in testing.
Samples of gear oil,in baby food jars can be placed in the refrigerator and freezer,and also heated in an electric double-boiler.
With a good cooking thermometer you can test the pour-point viscosity of the oil at different temps and get a feel for what heating will do.
One thing we know,is that whatever equilibrium temperature we achieve in the winter, will be nothing compared to a summer day at Furnace Creek,Death Valley,California,where gear oil would be plenty happy.
At one point,VW as going to use the Schacht',eutechtic (sp?) salt thermal storage system for warm cold-starts.It's a very sound engineering concept.

[nemo]

Originally Posted by Daox

To control it, I would ideally like to use a solenoid valve. I would also monitor engine temperature and transmission temperature. Normal operation would be to leave the solenoid closed until the engine is up to 130-140F. This gets it out of its high idle / cold start mode, since the engine is more important to warm up than trans. After the engine hits that temp, the solenoid would open up and the coolant would be used to heat up the transmission. At some set temperature, the solenoid could close if the transmission gets too warm. If not, it would happily run at ~180F just like the engine.

Is this overly complex? Perhaps. But, I will have at least one arduino onboard controlling another modification, so adding a temp sensor and a solenoid valve wouldn't be difficult at all.

Daox, I like how you would control it specifically waiting for the engine temperature to take it out of fast idle.

As for the hardware several thoughts came to mind. My first thought was to use a heater core but thought it might be better to just use flexible tubing that could be molded to the transmission shape so it could actually be in contact or is there a flat spot on the transmission. Insulating the tubes from the air would be required, also insulating the lines to the throttle body and heater might also be helpful. Bottom mounting location would be best.

As for a FE bump it's all speculation without some testing 7 mile is a short distance. My personal thought is thinner lube whether oil or transmission oil as other have said would probably yield similar improvement if compatible with transmission components. Both heat and lube change would be better.

Always hated the way vehicles felt in freezing weather.The mod could be worth it just for smoother shifting.