Factory tranny bypass

[weaponoffreedom]

As I am sure you all know, the LC\LX has a cooler bypass that needs to be pressed into position and held in place with a pin, when checking the fluid level.

Question is: Does that divert flow to the external cooler and away from the radiator heat exchanger? If not, how does in divert?

If one leaves the pin in place, does the fluid move to the external cooler 100% of the time?

 

[bloc]

The external cooler is on the same loop as the radiator heat exchanger, so the bypass can't send to one or the other.

Given the bypass pin must be pressed to do a fluid exchange, without it pressed I'm assuming most or all of the fluid stays within the transmission and it's own coolant/ATF heat exchanger.

 

[kcjaz]

Given the bypass pin must be pressed to do a fluid exchange, without it pressed I'm assuming most or all of the fluid stays within the transmission and it's own coolant/ATF heat exchanger.

^this is correct. Pushing the pin does the same thing as having the transmission thermostat open which allows the transmission fluid to circulate through the whole system including the front transmission coolers. I believe the main purpose of the little plate & frame HX on the transmission where the pin is, is to help warm up the transmission fluid on a cold start as the radiator fluid heats up more quickly. Plus with the tstat closed, your not initially cooling already cold transmission fluid by sending it through the air coolers up front.

 

[skrypj]

^this is correct. Pushing the pin does the same thing as having the transmission thermostat open which allows the transmission fluid to circulate through the whole system including the front transmission coolers. I believe the main purpose of the little plate & frame HX on the transmission where the pin is, is to help warm up the transmission fluid on a cold start as the radiator fluid heats up more quickly. Plus with the tstat closed, your not initially cooling already cold transmission fluid by sending it through the air coolers up front.

I suspect that is true. I have noticed my LX fluid warms up pretty fast.

My F150 used to literally take almost an hour to get up to full operating temp in the winter. Unless the torque converter was unlocked, it just didn't make enough heat on its own to warm up, and Ford's lockup strategy was aggressive and rarely ever unlocked once you were rolling. It also had a thermostatically controlled cooling loop but no warmer.

 

[bloc]

I believe the main purpose of the little plate & frame HX on the transmission where the pin is, is to help warm up the transmission fluid on a cold start as the radiator fluid heats up more quickly.

Also correct.

 

[weaponoffreedom]

I wonder at what temp the bypass opens? 195?

 

[misteracng]

On the 8 speed auto, I checked TIS procedures. There does not appear to be a cooler/tranny thermostat bypass to pin in the parts diagram and there is nothing in the procedure to pin it open. I can see this on the 6 speed auto. Can anyone confirm?

 

[gasman4u]

On the 8 speed auto, I checked TIS procedures. There does not appear to be a cooler/tranny thermostat bypass to pin in the parts diagram and there is nothing in the procedure to pin it open. I can see this on the 6 speed auto. Can anyone confirm?

No bypass/paperclip necessary on the 8 speed. I think you bring the transmission to appropriate temp to set fluid level using standpipe in drain hole.

 

[skrypj]

On the 8 speed auto, I checked TIS procedures. There does not appear to be a cooler/tranny thermostat bypass to pin in the parts diagram and there is nothing in the procedure to pin it open. I can see this on the 6 speed auto. Can anyone confirm?

I think the 8 speed might have a solenoid but I could be wrong. When I was doing my transmission fluid exchange there was some kind of wiring running to a device on one of the cooler lines

 

[TeCKis300]

Question is why?

If the goal is to improve transmission cooling, this won't do it. It won't have anymore ability to shed heat than when the thermostat normally opens.

Yet it won't have the benefit to self regulate to bring the tranny fluid up to a good working temp, while mimicing a 5 yr old driving herky jerky in the cold.

 

[skrypj]

Question is why?

If the goal is to improve transmission cooling, this won't do it. It won't have anymore ability to shed heat than when the thermostat normally opens.

Yet it won't have the benefit to self regulate to bring the tranny fluid up to a good working temp, while mimicing a 5 yr old driving herky jerky in the cold.

This. Add more cooler if you’re worried about temperatures.