Engine is 2008 Fit Sport A/T Turbo. I am adding an 8x11 B&M trans cooler and I would like to bypass the radiator as I plan on an upgrade and its "manual only"(no trans cooler).

I have read quite a bit on Honda autos and their trans cooler installs, all of them pertain to towing and the few times it was mentioned there was 'no need' to delete the original and just run them inline. I want to delete it for the aluminum radiator. I live in Las Vegas and the coldest it gets is right around freezing. (120 last week!)Will the auto trans warm itself up or does it need the engine heat? Thanks for any insight.

 

Heh, guess you are new. Yes the automatic transmission itself has a pump in it, which generates some friction, so at idle yes it will warm itself up. The engine heat itself im sure will radiate into it in park anyway. Are you planning on running a power steering fluid cooler as well? If you stick with the OEM Honda PS fluid, you should be fine, it doesnt expand anywhere near the amount auto-tranny fluid does.

 

New to automatics yes, older than you probably. You misunderstand so let me be more clear. Im adding an external trans fluid cooler, I want to bypass the factory trans cooler that resides in the bottom tank of the radiator. Some say that by doing this the trans might run too cold on start ups but if the trans needs a cooler to begin with then I would think it would reach normal operating temperature rather soon. I live in a very hot climate so no sub freezing weather to worry about. Power steering is electric.

 

BongoBennie, remember that the bottom of the radiator doesn't see "warm" coolant until the thermostat opens, so the idea of using the cooling loop inside the radiator to help bring the transmission fluid temperature up quickly is in fact incorrect. Feel free to bypass it and run hoses to the larger cooler core that you plan to use... the transmission will thank you for it. The key to long automatic transmission life is controlling the fluid temperature... more cooler means more life.

 

Thanks JR! That does make a lot of sense.

 

If you were wanting to consider warming up your a/t fluid faster (and given your application I don't see a need to) you could plumb in a physical thermostat for your a/t fluid before it goes to an external cooler, if you really wanted to. Again, I don't see this as needed. Your engine may warm up faster but so long as the coolant is doing its job, I've yet to see a stock Honda with an A/T that had temperature problems when everything worked correctly. As its regulated, I would consider as you have a turbo, a larger radiator and an external trans fluid radiator as you were planning.