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Discussion Starter #1
Please forgive me, hope I haven't missed the thread/link, but I have done a lot of searching/reading and still can't identify the tranny fluid return line (the cooled fluid returning to the tranny). I'm thinking it is the rubber hose/line attached to the metal nipple just above where the tranny pan bolts to the tranny case (yellow circle). Can anyone confirm? Anyone got pics of their auxiliary tranny cooler install? Thanks.
 

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Discussion Starter #3
FWIW, all 4.3 RAV4s have external auto tranny coolers (external of the tranny). LOL..........not even the factory "tow PREP pkg" equipped RAV4s have a auxiliary (secondary if u will) tranny cooler.:thumbs_up:
 

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I was thinking earlier how heat rises, so the line at the bottom of the radiator would logically be the cooler return line. All the other automatics I've owned had the tranny cooler at the bottom of the radiator.
 

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Discussion Starter #5
Radiators with top/bottom tanks usually do have the auto tranny cooler in the bottom tank.......side tank rads, the cooler is in one side or the other (except for the I4 hockey puck tranny cooler that's not in the radiator at all). The I4 tranny cooler is in the heater hoses, not the rad.

The last 5 auxiliary (seconday) coolers I've installed (GM and Jeep vehicles with side tank rads), the return line to the tranny has been the top line on the rad tank, the opposite of the V6 RAV4.
 

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The last 5 auxiliary (seconday) coolers I've installed (GM and Jeep vehicles with side tank rads), the return line to the tranny has been the top line on the rad tank, the opposite of the V6 RAV4.
That's interesting, I never would have guessed it. OK, here's the definitive proof--don't know why I didn't check here first--from toyodiy.com. The diagram clearly shows the inlet and outlet hoses at the transmission:

 

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Discussion Starter #7
It appears connector 32921G attaches to the tranny case just above where the pan bolts up. The tranny pan holds a reservoir of cooled tranny fluid that gets sucked up by the pump and sent to/thru the tranny and TC providing lubrication and removing heat from various tranny components.
 

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I guess the next fun and games will be hooking up to the tranny. Gotta do the same myself next so would be interested in seeing how you route the plumbing.
 

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Discussion Starter #10
I've decided to wait a few weeks to actually hook it up......going on a 1K mile road trip (not towing) and will continue to observe pre-towing tranny fluid temps (ScanGauge) for a bit longer/different driving conditions, before adding the auxiliary cooler into the loop. What I've observed so far is......tranny fluid temp rises very slowly (not towing) from cold start ambient temp to 200F (max observed so far) after 30-45 min driving around town. I'm a little puzzled to see 200F, not towing and driving easy. Have never seen motor coolant temp reach 200F even when the dash ambient temp was displaying 103F.

I removed the plastic splash shield on the bottom side for a "look around". With the splash shield removed, its easy to see/reach the tranny fluid hose running along the bottom of the radiator. That tranny fluid hose (32943A in the diagram and yellow circle) is where I will splice in using 3/8" brass fittings thus adding the auxiliary cooler into the tranny fluid loop.
 

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Discussion Starter #11
Update.....1200 mile round trip (not towing, auxiliary cooler not hooked up yet), lots of Interstate (up to 85 mph Texas hill country) and some residential (30 mph) driving, ambient up to 87F and max tranny fluid temp of 196F. Still seems hot for tranny fluid especially when engine coolant temp ran consistent mid 180s.:shrug: I would think if coolant temp ran 185ish (hot end of rad) then the cool end of the rad (where the factory tranny cooler is located) would be 10-20 degrees cooler than the hot end.:shrug: Something tells me this may be a hot running tranny even after the auxiliary cooler hook up (hopefully this weekend).:confused:
 

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I'm thinking about a transmission cooler as well. I saw 227F few times in my summer trip from LA to Portland, OR. Scan Gauge had shown this temperature.
 

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Discussion Starter #15
Yes, ours has the factory "tow prep pkg". I'm still baffled how hot the tranny runs when not towing, especially when the factory V6 tranny cooler is located in the "cool" end of the radiator.
 

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I would rate adding my B&M cooler as one of the best automotive decisions I have made. It has already paid for it self in the form of avoided costs of buying ATF.

200 deg fluid temperatures are not that crazy just means frequent flushing or even more frequent drain and fills. At least with my 4.2 Assin transmission toyota T IV fluid or mobil 3309 is all that can be used and its near the cost of full synthetic.

With my B&M cooler in place I see 180 ATF and 180 engine most of the time with it occasionally getting up to 190. Pre cooler I got all the way to 210 transmission and 190 or even 195 engine.

The reason my engine is also cooler now is the stock heat exchanger hocky puck.

At the temperatures I now see the fluid should last 100,000+ vs 15,000
 

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My car is 20000 miles on the clock.
If I install external transmission cooler, will it woid the 60000 mi drive train warranty?
Thank you.
 

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Once I clocked 250F in a tranny using IR sensor in a corolla driven 85 MPH in hot weather with AC on. I think toyota allows for those hot temps to boost fuel efficiency.
 

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My car is 20000 miles on the clock.
If I install external transmission cooler, will it woid the 60000 mi drive train warranty?
Thank you.
I would personally wait for the warranty expiration before doing that. Not worth the hassle if something brakes down.
 
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