Thread: What's a normal trans temp for the 4T65E?

I have a 2006 Pontiac grand prix with the 3.8 N/A version. I changed the trans fluid around 70k along with a new filter it has 104k on it now. My trans will run around 160-170 degrees when the temps outside are around 40 degrees. In the summer time when I'm driving to work (50 miles one way) the trans will sometimes reach 202 and 204 degrees. Most of my driving is at 70 mph it shifts fine and runs good. Is this normal?

Do I need to install a trans cooler? Is so what brand and where do I need to tap it in?

Originally Posted by GR8racingfool

^yup.

Those are normal temps.

GM wants them to run hot. Getting them to run cooler will just make things last a lot longer, including keeping your fluid from breaking down. I installed a B&M supercooler. Summer time mine doesn't reach higher than 170-175*F I don't drive it in the winter time now, but when I did, i would cover it up.

You want your trans. temp to be atleast 170* before you start romping on it.

Might also add, when I installed my cooler, its plumbed directly into my transmission, the radiator was capped off. I don't trust the factory radiators at all, not worth the risk of the side tank splitting and mixing your coolant with your transmission fluid, and wiping out your transmission 90% of the time. Seen it happen too many times.

~F~

Do you have any pictures of your setup? I would like to see how you capped it off from the radiator as well. Also do you have a part number or a link to the trans cooler your running?

I think the temperature you have is perfectly normal.