Uh Oh... Whaddya Think?

[Bronc Rider]

Re: Uh Oh... Whaddya Think?

Don't go for the cheap cooler, but don't go for the Toy one at $450 either.

Best coolers out there have some flow control to them. When the fluid is cool, the second radiator is bypassed. Only when the fluid warms up does it go through the cooler. Otherwise your tranny may take longer to get to normal operating temps and that isn't good either.

Installing them is dirt easy, but if you don't feel up to it any decent tranny shop can do it. Crap, I'd even trust Aamco to do it properly, that's how simple it is.

BTW, putting one in is the right decision. I'd also go with a tranny temp gauge, but I'm pretty anal when it comes to towing.

$450 is way too much. Check this one out: http://www.summitracing.com/parts/BMM-70273/ Im not saying to go with that one. I'm just showing you how inexpensive they are. I have used that one before and it dropped my towing temp down 25 degrees so, its not a bad unit for the money spent on it. They also sell thermostats to plumb in with a cooler if you wanted one.
Here is a link to another forum where someone mounted a cooler with a thermostat and extra filter: http://fullsizebronco.com/forum/showthread.php?t=74305&highlight=cooler This diagram is from that link :

I doubt you want something that elaborate but this may give you some ideas.

EDIT: I run mine the same way, bypassing the radiator. My theory is that if the oil cooler in the rad goes out, you wont mix water with your tranny fluid. Some people go through the radiator then the cooler. Its a matter of preference.

 

[jeeperman]

Re: Uh Oh... Whaddya Think?

If the add on cooler is installed up stream of the O.E.M. trans cooler inside the radiator the add on cooler purpose is defeated. The engine and trans will want to run at the average temps of the engine and trans.
The trans is engineered to run at the same as ideal engine temp. If the engineers wanted the trans to operate at cooler temps the O.E.M. cooler would not be mounted inside the radiator.

Thus the optimum set up is to install the trans cooler downstream of the rad with a thermostat to bypass the second cooler until trans temps reach or surpass engine temps.

 

[jkust]

Re: Uh Oh... Whaddya Think?

What is the tow capacity of that vehicle without the tow package? Bummer it doesn't have the factory package since it is a cheap option.

 

[Bronc Rider]

Re: Uh Oh... Whaddya Think?

If the add on cooler is installed up stream of the O.E.M. trans cooler inside the radiator the add on cooler purpose is defeated. The engine and trans will want to run at the average temps of the engine and trans.
The trans is engineered to run at the same as ideal engine temp. If the engineers wanted the trans to operate at cooler temps the O.E.M. cooler would not be mounted inside the radiator.

Thus the optimum set up is to install the trans cooler downstream of the rad with a thermostat to bypass the second cooler until trans temps reach or surpass engine temps.

Like I said, its a matter of preference.
If you go to that site I linked you can find tranny shops that sell their stuff there and they recommend the set up in the diagram. These guys build tranny's that hold up to 1500 hp so I find their advice to be sound. My truck has 270,000 miles on the original tranny. I have ran the set up above since 1995. The tranny is still holding up so I highly disagree with the statement I quoted.
Keep in mind it is a matter of preference no matter how you slice it.

 

[Bronc Rider]

Re: Uh Oh... Whaddya Think?

One more thing to add:
The tranny should run at a similar temp as the engine. When towing, the tranny will usually climb above that and thats when a cooler becomes a necessity. The fluid running to cold can also can issues, thats why there is a thermostat in the diagram.

 

[jeeperman]

Re: Uh Oh... Whaddya Think?

I agree with you Bronc Rider as noted in the link you provided with the diagram, the person posting that admitted that during cooler weather the trans took for ever to get to operating temp. So he added the thermostat to bypass the second cooler until the temps came up.
So if you still use the in-rad cooler, it will warm the tranny faster. And the add-on cooler and thermostat would then make sure it stayed at the right temp.

But yes, if your worried about rad fluid getting into the trans then bypass the rad cooler.

 

[timmyjoebob]

Re: Uh Oh... Whaddya Think?

What is the tow capacity of that vehicle without the tow package? Bummer it doesn't have the factory package since it is a cheap option.

Okay... I get to the repair shop ready to plop down about $200 to get the cooler put in. Mind you, this is an '04 Highlander that we bought new without tow bar, etc.

They get the car up in the air, begin taking out the plastic undercarriage stuff to look at mounting options and...

The mechanic comes and gets me to look at something. He says, "Mr. Harrison, I'd like to take your money today, but... you already have a transmission cooler of decent size installed... look here.

He points -- not downstream of the radiator or outside the radiator, but down and to the right, just inside the left fog light (as you're sittin in the driver's seat). Evidently, my Highlander does have the factory tow package, just without the tow bar.

My manual says 3500lbs tow capacity. It gives no info about the capacity without the tow package. (I was guessing a 1000-1500lbs less anyway without the tow package).

So, I had my automatic transmission fluid changed while they had it up in the air and I figure I'm good to go.

 

[ezmobee]

Re: Uh Oh... Whaddya Think?

Great news. Good idea getting the fluid changed while you were there anyway.

 

[jeeperman]

Re: Uh Oh... Whaddya Think?

Thats good, but did you get a tow bar too ??