Transmission Cooler and Gauge

[RacerDude]

Just thought I'd post the story and pics of today's project in preparation for this summer's towing season.....

Thanks to TeryT for the idea of moving the horns to the passenger side - worked great.

I was able to find an inline connection for the temperature gauge sender (as also got the cooler and gauge) here:

http://www.importperformancetrans.com/coolers.shtml#main

Anyway, after some troubleshooting with different hoses disconnected I was able to determine the flow of the fluid. The 2 lines from the tranny come up the passenger side, one on top of the other. The hot fluid comes forward in the bottom one and goes through the radiator cooler first, then across and through the auxiliary cooler and then back to the tranny through the top line. One thing I found interesting is that the fluid actually goes UP through the auxiliary cooler (in the bottom connection first) so this is how I connected the larger cooler also. From the factory there are conveniently two flexible hoses connecting the hard lines from the tranny to the hard lines just behind the bumper. I plumbed in the inline temperature sensor in the flexible return line, so I'm measuring the fluid at it's coolest just before it goes back into the tranny. The cooler fit in the stock position with very little modification, basically just drilling a couple of new mounting holes in the cooler and one of the supplies metal straps. And moving the horns over to the left side, which I just bolted onto one of the existing A/C condenser mounting bolts after extending the wires. Another note on the inline sensor is that I has to physically connect a ground wire from it to the frame, since the sensor expects to be actually IN the tranny and not insulated by rubber hose. I accomplished this by using a hose-clamp to clamp the wire to the sensor housing. Worked great.

Anyway, following are the pics.

BEFORE: (Stock)

 

[RacerDude]

AFTER:

 

[RacerDude]

Sorry for the fuzzy pic of the sensor assembly....guess I was too close. And now I would have to take the skid plate off again to get another pic.

 

[RacerDude]

And here's the gauge inside

 

[LV4R]

How is the unit working? Nice install! I will probably buy this kit and install it too. I am just curious if everything is working ok.

 

[RacerDude]

Everything seems to be working OK. I haven't seen tranny temps above 125 yet. It's not been very warm here, so not really a good test. We're leaving for Kalispell in the morning, so I'll have a better idea after towing over some mountains. The gauge is working great.

RD

 

[Xtrm-farmers]

Looks good! The only thing I would want is a temp reading from the transmission instead of the fluid after its cooled. But knowing the fluid temp at any point is better then not knowing it at all. If someone has a shop manual for the 03+ 4runner, please email me. Since Toyota does have a temperature sensor on the tranny, I think we are able to get a reading off that sensor. I would love to take a look into it.

Thanks
Xtrm-Farmers

 

[mikestang]

JI plumbed in the inline temperature sensor in the flexible return line, so I'm measuring the fluid at it's coolest just before it goes back into the tranny.

Nice write up, however, you should of installed the temperature block right where the fluid exits the tranny. You want to know how hot the tranny is running, not it's temp. after the fluid has been cooled.

 

[Koz]

You want to measure the temp in the trans pan, this will give you the actual temp that is going into the trans.

Koz

 

[mikestang]

Like someone said, any measurement is better than no measurement, but I have to disagree with you. In order to get an idea of what's going on in the tranny, if it's being overworked or not, you want to see the fluid temp at its hottest point. It's irreletive what the temp is going into the trans, this does not represent how the tranny is operating. Measuring pan temp or temp after the radiator/cooler pass will tell you if your cooling items are cooling, but it won't show you how hot the tranny is getting, which is really what you want to know.

 

[Koz]

Here's what I think and know. I know that the ideal operating temp is 175 degrees and for every 20 degrees over it cuts the life of the fluid in half. So at 175 it will last 100K miles, 195 will last 50K and 215 will last 25K. Now to monitor that temp this would be done at the sump/pan. I think that if you really want to know exactly what is going on in your trans you would want to install TWO sensors, one in the pan and one at the hottest point coming out of the trans before cooling (before and after going through the trans). You could use 2 separate gauges or set up a toggle switch between the 2 sensors before the gauge. Just Thinking!:nerd:

Koz

 

[RacerDude]

Guys,

The 2 sensor setup is what I am eventually going to have, only not in the pan since I don't want to hassle with having a NPT adapter brazed in. I'll put the other sensor in the hot line and toggle it with a switch like Koz mentioned. I just haven't been able to get my hands on another sensor by itself yet -- the one I have now came with the gauge and I won't need another gauge. I debated with myself for a long time on which line to put the initial sensor in. At least I know the tranny is getting nice cool fluid back in. It will be very interesting when I get the hot line sensor in to see the difference in temps back-to-back and see exactly how efficient the cooling is.

That is if I don't just go get a bigger truck to pull this thing with, I've been having second thoughts on dragging around something this length (26') and weight (6400). The power is fine but windy conditions can get a little interesting. Also thinking about biting the bullet and forking out the dough for a Hensley Arrow.

I don't WANT to trade the Runner, but I also don't want to regret NOT doing it if something happens down the road.

RD

 

[Koz]

Guys,

The 2 sensor setup is what I am eventually going to have, only not in the pan since I don't want to hassle with having a NPT adapter brazed in. I'll put the other sensor in the hot line and toggle it with a switch like Koz mentioned. I just haven't been able to get my hands on another sensor by itself yet -- the one I have now came with the gauge and I won't need another gauge. I debated with myself for a long time on which line to put the initial sensor in. At least I know the tranny is getting nice cool fluid back in. It will be very interesting when I get the hot line sensor in to see the difference in temps back-to-back and see exactly how efficient the cooling is.

That is if I don't just go get a bigger truck to pull this thing with, I've been having second thoughts on dragging around something this length (26') and weight (6400). The power is fine but windy conditions can get a little interesting. Also thinking about biting the bullet and forking out the dough for a Hensley Arrow.

I don't WANT to trade the Runner, but I also don't want to regret NOT doing it if something happens down the road.

RD

The new 07 Tundra might be the ticket for you with its 10K lbs. tow rating and a decent wheelbase.

Koz

 

[RacerDude]

Yes you are very correct and I have had that thought in my mind also........but finances will probably veto that choice since I expect an '07 DoubleCab will probably sticker somewhere over $40K, out of my budget for now. Which means waiting until they start showing up on the used market.

Back on the sensor placement, Saturday I moved the sensor to the hot side. On the trip home today I saw a max of 210 pulling Snoqualmie Pass in Washington. I think it was 58 outside at the time. But the fluid is this hot for only a few seconds until it goes through the coolers. I was seeing 165 max on the cool side with the same conditions. On level ground, 75 outside, 4th gear (locked) it was running 150 on the hot side. So it looks like I'm good to go as far as temperatures. I'm assuming temps in the pan would be somewhere between the high and low lines. It was interesting to see how quickly the temps would jump up from 150 as soon as I would downshift to 3rd and start pulling the hills.

BTW, the trip home was much more enjoyable as the winds had calmed down considerably.

RD

 

[Koz]

Yes you are very correct and I have had that thought in my mind also........but finances will probably veto that choice since I expect an '07 DoubleCab will probably sticker somewhere over $40K, out of my budget for now. Which means waiting until they start showing up on the used market.

Back on the sensor placement, Saturday I moved the sensor to the hot side. On the trip home today I saw a max of 210 pulling Snoqualmie Pass in Washington. I think it was 58 outside at the time. But the fluid is this hot for only a few seconds until it goes through the coolers. I was seeing 165 max on the cool side with the same conditions. On level ground, 75 outside, 4th gear (locked) it was running 150 on the hot side. So it looks like I'm good to go as far as temperatures. I'm assuming temps in the pan would be somewhere between the high and low lines. It was interesting to see how quickly the temps would jump up from 150 as soon as I would downshift to 3rd and start pulling the hills.

BTW, the trip home was much more enjoyable as the winds had calmed down considerably.

RD

The temperature difference between putting the sensor in the pan and the line after cooling is approx 5 degrees, so going through the trouble of installing the sensor in the pan is not worth the trouble. The hottest time for the trans/fluid is backing up an incline.

Koz!

 

[Heavytower]

Hi RacerDude,
I have not checked in for a few months! My temps are MUCH higher. With a Cyberdyne guage and sensor on output cooler line of transmission I am reading about 220F on the highway on an 85F day. In city traffic I pin the guage at 260F occassionally, probably never going above 270F. After a long discussion with my service dept. at Toyota, they confirmed with the coroprate office that I should not be concerned until the "trans. temp. light" came on. It is set at 300F!!!!!!! They said "synthetic fluid is good to that temp". I explained that they must install a larger trans. cooler if they claim you can tow 7000lbs. ( I am towing a 5000lb 25rss, probably maxing out at 6200lbs, loaded). They also said they are only interested in the temp. AFTER cooling - I think they are wrong!!! My parting words were I think they will be replacing the trans. at least once a year!!(under warrantee).

2005 4Runner sport 4wd V8 towing a 25rss Keystone Outback travel trailer with a loaded weight of 6200lbs.

 

[greasefingers]

Search under the user name TeryT. I believe he brazed on a tranny pan sensor?