6R80 Thermal Bypass Valve Removal

[Ecto1]

Has anyone removed the Bypass Valve in their 6R80? Now that I know mine has a Thermal Bypass Valve I'm thinking I might be better off without it. The Trans temps do get a lot warmer than I'd like and I'm hoping that removing the Bypass Valve will allow the Trans to run a lot cooler. Apparently there are "Bypass Valve Delete Kits" available for this reason.

Any downsides to operating the trans without the OEM Thermal Valve? I have no intentions of racing the car, just normal grocery getting and highway cruising. Occasional light towing.

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[offroadkarter]

Define "warmer than I'd like", 6R80's are meant to run in a 180-215 range give or take.

 

[PSI]

There would be zero benefit. Trans temp is only something to start worrying about from 230 on up.
These modern fluids can handle much more heat than the older conventional fluids.

 

[Ecto1]

Well... My trans temps routinely reach 210ish. That seems high to me. Everything works fine but I'd prefer temps well under 200. More like 180ish. I can't see how higher temps improve durability.

The other issue is flushing the trans. With the bypass valve in the way it makes replacing the trans fluid a more frustrating problem.

Just looking for any one with experience removing this valve.

 

[PSI]

Whether or not removing the thermostat would actually improve reliability, I can’t say. Maybe it would. I will say that I’ve had two 6R80s and one 6R140 that have all been perfectly happy at factory temps, including lots of towing with two of those transmissions. I’m not the only one, the 6R units have reliability that could be considered legendary, with the exception of the lead frame issues that some have had.
Of course I also have an old GM 4L80E that has been over cooled for over 100k miles with no thermostat and it is doing well too.
I just don’t think they’re that sensitive in general unless you truly overheat them.

 

[Ecto1]

Whether or not removing the thermostat would actually improve reliability, I can’t say. Maybe it would. I will say that I’ve had two 6R80s and one 6R140 that have all been perfectly happy at factory temps, including lots of towing with two of those transmissions. I’m not the only one, the 6R units have reliability that could be considered legendary, with the exception of the lead frame issues that some have had.
Of course I also have an old GM 4L80E that has been over cooled for over 100k miles with no thermostat and it is doing well too.
I just don’t think they’re that sensitive in general unless you truly overheat them.

Thanks. It's the recall on the 6R80s in the F150s that got me started down this rabbit hole. First I found out about the Lead Frame headaches and decided my trans was overdue for a fluid & filter. 11 years & 60K miles. But the only practical option with this trans is a flush. Except that the bypass valve prevents a flush from replacing anything but the fluid in the radiator trans cooler. So, if I have to remove the pan to do a drain & fill I figured it might make sense to remove the stupid bypass valve while I'm at it. Makes a flush more realistic and in theory lowers the operating temps. Seems like a win/win to me.

Since I don't know if there are any down sides to removing the bypass valve I'm waffling.

Thanks again.

 

[Zrussian13]

Most good transmission shops i know will tell you not to flush the transmission. Just drain and refill. Flushing can cause metal shavings to recirculate through the trans and cause premature failure. I don't know how much truth there is in this but it makes sense, especially a transmission that's at least 9 years old.

Also, if your not putting your car through extreme conditions (racing, heavy towing) i wouldn't be considering the bypass delete. Modern cars are designed to run warmer. I wouldnt be over thinking it under normal circumstances.

 

[Skye]

I do not have an answer.

Without an answer and data I can study, I'd prefer the valve in-place for a street-driven car.

Retaining the valve will allow the transmission to come up to its operating temperature quicker. I'd think temps would be more stable with it. As with the engine's coolant thermostat.

My car has radiators for the engine coolant, engine oil, trans oil (Manual) and diff. Some are controlled by valves and pumps, some aren't.

In my examples, I'm not one to question what Ford did. I don't have the education, experience or data leading me to change things.

For those with trans and vehicle mods or that track occasionally or frequently, things do change. There is history and guidance from others to support making adjustments.

For the topic in-general, I'd start by trolling threads to see what others typically see, under similar conditions. If you're exceeding those temps, I'd then start studying why. Maybe it is the valve. Maybe it's a small cooler or poor airflow throughout the engine bay.

Several have installed a larger trans cooler. There is also a track cooling thread with ideas and examples showing how to improve cooling in-general.

https://www.mustang6g.com/forums/threads/the-big-fat-track-car-cooling-thread.53695/

https://www.google.com/search?q=mus...Hc3kEawQrQIoAnoECB0QAw&biw=1460&bih=740&dpr=2

https://www.google.com/search?q=mus...HbTPFwgQrQIoAnoECB4QAw&biw=1460&bih=740&dpr=2

YMMV.

Edit,

For maintenance, the schedule in the Owners Manual is the minimum standard. You could improve on that by using well-known fluids and Ford or premium filters. You could also change the fluid more frequently. Each person will be different. I did not check if Ford has a Severe Duty schedule.

My experience with flushing did not go well. Years ago, "power flushing! " was justing coming out. In the truck I had, it seemed like a good idea. I found out after-the-fact it was a great way for the techs to blow out every seal, leaving me to begin replacing several a few hundred miles later.

Flushing can be useful if there was damage and you believe some of the aftermath circulated through any coolers. Otherwise, I'd just drain, replace filter and refill.

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