Transmission Temperatures and How it Relates to Life of the Fluid

[octanejunkie]

I can't find data or literature that shows a low-temp bypass in the B&M 70264. Where can I find info on this? I want to run this in series with my OEM setup, but it is important to me that trans fluid gets up to temp normally.

Both B&M and TruCool have rads that incorporate a low-temp bypass feature which is actually not temperature dependent, it's fluid viscosity based. Cooler, thicker fluid cannot pass into the cooling fins and is "rejected" through the bypass. Once hotter, and thinner, the fluid fills the core and passes through the cooling fins. It's simple and elegant.

 

[19963.4lsr5]

Both B&M and TruCool have rads that incorporate a low-temp bypass feature which is actually not temperature dependent, it's fluid viscosity based. Cooler, thicker fluid cannot pass into the cooling fins and is "rejected" through the bypass. Once hotter, and thinner, the fluid fills the core and passes through the cooling fins. It's simple and elegant.

And B&Ms cooler is made by TruCool. The machine shop that made them (Long Manufacturing) sold to Dana.


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[mtbtim]

https://static.summitracing.com/global/images/instructions/BMM-bm_cooler_techdoc.pdf

Check last page for "LPD" feature.

Here's the description Amazon gives for the B&M 70264:

Product description
Adding this B&M SuperCooler keeps the ATF and transmission cooler, and keeping a vehicle's transmission cool is essential for dependability, especially in performance applications. The unit is designed to be very efficient for its size and weight, to cool much better than an ordinary 'fin and tube' cooler, and to reduce the risk of lube system failure. Using fluxless, oven brazed construction for vibration resistance, it is built out of lightweight aluminum alloy and features a revolutionary 'stacked plate' design with multiple oil flow paths. The unit monitors resistance to flow by allowing a controlled amount of ATF to pass through a self-regulating orifice. Controlled by viscosity, thicker ATF is returned directly to lube through two bypass openings in the stacked plate core, while thinner ATF is directed through the core to cool as operating temperatures increase.

 

[mtbtim]

And B&Ms cooler is made by TruCool. The machine shop that made them (Long Manufacturing) sold to Dana.


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In the FAQ section of the Trucool website, look at what they say about bypassing: Frequently Asked Questions | Tru-Cool

Should I disconnect the radiator in-tank oil cooler when I install a Tru-Cool cooler?

Do not disconnect the in-tank oil cooler if you can avoid it. Your in-tank cooler offers additional cooling and helps preheat the transmission. In colder climates the in-tank cooler should never be disconnected from the system.

 

[19963.4lsr5]

In the FAQ section of the Trucool website, look at what they say about bypassing: Frequently Asked Questions | Tru-Cool



Should I disconnect the radiator in-tank oil cooler when I install a Tru-Cool cooler?



Do not disconnect the in-tank oil cooler if you can avoid it. Your in-tank cooler offers additional cooling and helps preheat the transmission. In colder climates the in-tank cooler should never be disconnected from the system.

That's how I feel too. The puppy hauler I bypasses because I seen wisps of white in the ATF. Now it's a new rad as part of the head gasket job and the rad cooler will be hooked back up.


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[spartacus]

I can't find data or literature that shows a low-temp bypass in the B&M 70264. Where can I find info on this? I want to run this in series with my OEM setup, but it is important to me that trans fluid gets up to temp normally.

For a data point / FYI:
For my 100% current OEM setup: Normally I see scangauge trans temps 205F or below for normal use. If I'm driving a ton on a hot day up to 210F. If I'm driving in mountains 230F. If I'm on steep mountain roads in 2nd gear at lower speeds (35mph) on a hot day I have seen 248F. 4LO offroading / rockcrawling I have never gotten over 210F.

yours temps are a tad high. keep your OD off when in the mountains and when going up switch backs or dirt on incline keep it in 4x4i and that would keep help the temps down. I think you could definately benefit from putting a external cooler in series. Replace your atf around 20k mikes and youll be fine. I've driven a lot in the mountains and have the same tranny with almost 400k miles.

 

[theriddler]

Both B&M and TruCool have rads that incorporate a low-temp bypass feature which is actually not temperature dependent, it's fluid viscosity based. Cooler, thicker fluid cannot pass into the cooling fins and is "rejected" through the bypass. Once hotter, and thinner, the fluid fills the core and passes through the cooling fins. It's simple and elegant.

Thank you for explaining this. I talked to Shawn from TruCool yesterday to confirm the 4590 had a low temp bypass and he said it did but it was kind of confusing the way he explained it...your statement cleared that up for me. So yes, it's a low temp viscosity based bypass and NOT a true thermostat...and that's ok. A good idea actually. I don't feel the need to run it to the radiator anymore after confirming this...one pink milkshake is enough for me.

I was concerned about the fluid not being able to get up to temp fast enough with cooler weather on the way in a couple months. I don't know about you guys but my 4runner does NOT want to shift out of first gear when it's not up to temp.

 

[Drcoffee]

Thank you for explaining this. I talked to Shawn from TruCool yesterday to confirm the 4590 had a low temp bypass and he said it did but it was kind of confusing the way he explained it...your statement cleared that up for me. So yes, it's a low temp viscosity based bypass and NOT a true thermostat...and that's ok. A good idea actually. I don't feel the need to run it to the radiator anymore after confirming this...one pink milkshake is enough for me.

I was concerned about the fluid not being able to get up to temp fast enough with cooler weather on the way in a couple months. I don't know about you guys but my 4runner does NOT want to shift out of first gear when it's not up to temp.

So its a toyota design to keep the transmission in a lower gear until the coolant reaches a specific temperature which you will see when the needle is between low and midway. The ecm is programmed to do this in order to warm the enging faster. If you pay attention to the coolant temp, it will happen at the same point every time and you will feel the trans upshift. Put on the cooler and install a gauge on the dash if you want to monitor it. I would be/am more concerned about cooking the ATF :flame: than running it cool.

 

[theriddler]

So its a toyota design to keep the transmission in a lower gear until the coolant reaches a specific temperature which you will see when the needle is between low and midway. The ecm is programmed to do this in order to warm the enging faster. If you pay attention to the coolant temp, it will happen at the same point every time and you will feel the trans upshift. Put on the cooler and install a gauge on the dash if you want to monitor it. I would be/am more concerned about cooking the ATF :flame: than running it cool.

Yeah me too! We have 3 3rd gens in our family but mine seems like it takes forever... Definitely a lot longer than the other two. No big deal just strange. If that's the only thing wrong I'm doing good I guess.

 

[DK327]

If you pay attention to the coolant temp, it will happen at the same point every time and you will feel the trans upshift. Put on the cooler and install a gauge on the dash if you want to monitor it

Indeed, mine ALWAYS shifts @ 130F, never before.

 

[Drcoffee]

Yeah me too! We have 3 3rd gens in our family but mine seems like it takes forever... Definitely a lot longer than the other two. No big deal just strange. If that's the only thing wrong I'm doing good I guess.

If it takes longer, your thermostat might be failing and opening too soon.

 

[theriddler]

That makes sense, I haven't done a coolant flush or thermostat change on this vehicle yet so I'll do that. I was thinking maybe the temp switch wasn't accurate anymore but on my obdii scanner it reads accurately. Thanks!

 

[phattyduck]

I don't know about you guys but my 4runner does NOT want to shift out of first gear when it's not up to temp.

It should use 1st and 2nd when cold. It shifts into 3rd and OD once coolant temps reach 130*F, as Dr Coffee said.

If your trans is truly staying in 1st when cold, there may be a problem.

-Charlie

 

[theriddler]

I still need to do a fluid change and filter cleaning, I'll report back how it shifts after that. Other than the slow shifting when cold, it runs great. It's just odd when i leave work and try to accelerate to 30-40mph it just refuses to shift until the engine temp rises. The other 2 3rd gens I've owned hasn't been this bad.

 

[19963.4lsr5]

I still need to do a fluid change and filter cleaning, I'll report back how it shifts after that. Other than the slow shifting when cold, it runs great. It's just odd when i leave work and try to accelerate to 30-40mph it just refuses to shift until the engine temp rises. The other 2 3rd gens I've owned hasn't been this bad.

Does your trans have a TV cable? If so try putting a little slack in the adjustment.


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[theriddler]

I have no clue about that, I thought it was all electronic