Transmission too cold?

[itsbo1313]

So it’s been cold lately and my tranny hasn't got over 105 degree’s. Should I be concerned?

 

[swathdiver]

So it’s been cold lately and my tranny hasn't got over 105 degree’s. Should I be concerned?

Nope. Mine rarely gets to minimum temps which is 158 for the HOT fill check. Still going strong!

 

[Donnie Yukonie]

Nope transmissions are essentially a big hydrualic pump. being a bit "cold" is better than too hot. heats the worst enemy of any trans.

 

[Doubeleive]

i have mine modified to run cool and it will sometimes run that low, no problems

 

[itsbo1313]

Okay, thanks.

 

[Miami-Dade]

Nope transmissions are essentially a big hydrualic pump. Being a bit "cold" is better than too hot. Heats the worst enemy of any trans.

I just had my transmission replaced last week due to the heat killing it.

 

[itsbo1313]

I had mine rebuilt before we moved out of California. 30k miles later I’m debating a tranny flush or drain and fill.

 

[Charlie207]

It's been stupid-cold around here lately, and yesterday the ATF temp didn't hit 100* F (per the dashboard digital gauge) until almost 45 minutes of constant driving. For the first 20 mins it was at like 30*F and felt like molasses.

 

[SNES Avalanche]

I had mine rebuilt before we moved out of California. 30k miles later I’m debating a tranny flush or drain and fill.

Drain and fill.

 

[Geotrash]

I've done a ton of reading about this topic over the past year, and so far I haven't found a single person who knows precisely why GM (and other manufacturers) explicitly recommend a minimum continuous operating temperature for transmission fluid. For the 6L80E for example, it's 150ºF. Some speculate that it's for fuel economy reasons, and others speculate that cooler fluid being more viscous, can increase wear in some components. Not only does it appear in GM service literature, but some transmissions ship from the factory with thermostats designed to allow the fluid to warm up to operating temperature faster before sending fluid through the external cooler.

For some reason seemingly unknown to the universe of shade-tree mechanics and forum participants, there is a minimum recommended operating temperature for transmission fluid. Anyone know a GM (or other) powertrain engineer who can answer that question for us? Without that key insight, we're all just speculating about ideal transmission temps, or if running them cooler than 150ºF has any consequences worth managing differently.