Hi,

I have a transmission cooler fitter to my VRX AWD. Anyone know of a suitable in-line bypass thermostat so it doesn't cool the oil excessively? I live in Canberra and wouldn't want to harm the transmission by over-cooling it during winter. As it is, I've noticed from the relationship between road & engine speed that the transmission takes longer to reach normal operating temperature with the cooler fitted.

You can get good control over the temps by the way you hook it up.
Cooler climates - put it before the radiator - so the radiator heats it again before returning to the Tranny.
Warmer climates - put it after the radiator - reduces the amount of heat put into the oil from the radiator.

I've seen removable "sheilds" used to reduce air flow onto the trans-cooler for the colder seasons in some countries.

I can get deraile units they bypass when fluid temp is cool if that is what you are after

Just a question, does it hurt to run he tranny a bit on the cool side? I've got a V8 cooler in mine & still plays up when I give it a hard time, thinking of getting something bigger but don't want to overcool if thats a bad thing?

You can get good control over the temps by the way you hook it up.
Cooler climates - put it before the radiator - so the radiator heats it again before returning to the Tranny.
Warmer climates - put it after the radiator - reduces the amount of heat put into the oil from the radiator.
Thanks,

I already have the auxilliary cooler taking the feed from the transmission before it goes to the cooler in the radiator. The way I figure it, that should allow the stock cooler to add a little extra cooling if the oil's still too hot after exiting the auxilliary cooler, and warm it up a bit if it's too cool. I'm not confident the latter will be enough with sub-0 weather, though.

I've seen removable "sheilds" used to reduce air flow onto the trans-cooler for the colder seasons in some countries.
Not a practical option with a VRX, I'm afraid - the auxilliary cooler can only be accessed by removing the entire front bumper. In any event, I could just as easily disconnet the auxilliary cooler.

I can get deraile units they bypass when fluid temp is cool if that is what you are after
Hi Mal,

That's probably the kind of thing I'm after. Any idea of $?

Just a question, does it hurt to run he tranny a bit on the cool side? I've got a V8 cooler in mine & still plays up when I give it a hard time, thinking of getting something bigger but don't want to overcool if thats a bad thing?A little on the cool side is probably a good thing, but I've got some serious cooling going on - two series 2 coolers in-line, for extensive caravan towing. Last year I went up north,via the east coast all the way to Darwin & back. Later this year, I'm planning to head back up to Katherine and around the west coast.

If you over-cool the fluid, you might end up with condensation build-up in the transmission. Not good. Plus, having the transmission continually pumping high-viscosity oil (if it's too cold by the time it exits the cooler(s)) can't be good, either.

Mal's suggestion sounds like it could work if you could "tune" the temperature at which it will bypass.
Another option would be to tee into the lines before & after the cooler, run a bypass line and install 2 valves so that you can simply switch between using the cooler or bypassing it altogether. Put the pre-cooler isolation valve after the tee on the bypass line, then put the post-cooler isolation valve after the cooler before the tee!
Just make the valves easy to access!

I found something that might do the job:
http://www.bulkpart.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=2&Product_Code=708-4739&Category_Code=cooler-fittings
Anyone know where I can get these (or an equivalent product) locally?