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1999 Toyota RAV4 with 3MZ-FE 6 cylinder engine, camo wrap, OME lift, heavily modded
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Discussion Starter #1
On the E250F manual 4x4 transaxle, which cooling line is the output? I'm adding an oil temperature sensor and naturally I want it to be in the line leaving the transaxle rather than returning with cooled oil. I've looked in various manuals and I haven't been able to determine it. If I have to, I can leave one hose disconnected from the oil cooler and see which line is pumping fluid.

History, I had a transaxle failure due to a failed cooling line and I want to be able to see what is actually going on with a transmission oil temperature gauge.

This my post concerning replacing the destroyed transaxle. http://www.rav4world.com/forums/85-4-1-faults-fixes/215738-replacing-manual-transmission-project.html
 

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Good idea. However, your problem was losing your oil.

If you have a temp sender in the line leaving the g/box, the temp will be OK until all your oil is pumped out, the it will slowly go down. Better in the return, then temp will be OK as long as oil is returning to the g/box.

Maybe pressure would be better, as soon as it loses flow, it will go down? Best in the return again I think.

Fitted at the return connection to the g/box best option I think.
 

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1999 Toyota RAV4 with 3MZ-FE 6 cylinder engine, camo wrap, OME lift, heavily modded
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Discussion Starter #3
Good idea. However, your problem was losing your oil.

If you have a temp sender in the line leaving the g/box, the temp will be OK until all your oil is pumped out, the it will slowly go down. Better in the return, then temp will be OK as long as oil is returning to the g/box.

Maybe pressure would be better, as soon as it loses flow, it will go down? Best in the return again I think.

Fitted at the return connection to the g/box best option I think.
According to my wrench turner group, that as the oil pressure drops the tranny temp will rise as it is not cooling as efficiently. I had space for three aftermarket gauges and I wanted to know which three would provide the best information. We all agreed an oil pressure, oil temperature and because the transaxle already has a cooler a transmission oil temperature gauge. A coolant temp gauge isn't as necessary as oil temp because if you are overheating from any cause it will show up as an oil temp increase as well. Part of the logic that oil pressure will remain fairly constant until the pump looses prime, however, the tranny will heat up as it loses lubrication. I still may not be able to prevent another catastrophic failure but being I'm not reading about this being a constant issue, it hopefully is a onetime event. The gauge is probably more of a feel good thing anyway.

To put a gauge in, I have to have a point to install the sensor. I was looking for any info on which hose is the output so that I can put the sensor in that line.
 

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I still think the sensor is no good in the line out of, or even into the g/box.
It should be fitted into the g/box casing, below the fill plug, so you get the actual temp in the g/box, plus if you get a leak, the level will drop below the sensor.

Yes, the g/box will heat up if it loses lube, but if the sensor is in the exit hose, it won't show an increase, nor probably any change until all your oil is gone, then the temp will drop. In the return hose at least, if your cooler or output hose goes, it won't be getting any oil, so the temp will change.

You can get some temp gauges the just attach using a convenient bolt, on the head/block, so could be used on the g/box instead.

Like you say, whatever you do is better than nothing.
 

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1999 Toyota RAV4 with 3MZ-FE 6 cylinder engine, camo wrap, OME lift, heavily modded
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Discussion Starter #5
I didn't want to drill holes in the tranny case for obvious reasons, and the sensor protrudes quite aways so it may interfere with something internal. There aren't a lot of bolt holes low on the tranny that aren't bolting something down I guess I could drill and tap through the drain plug, that would get it in there. I'm draining the gear oil in the morning and refilling, I could take a look at the drain plug and see if it is substantial enough to install the sensor. Usually you put sensors in locations where fluids are moving that's another reason I was going for in line.
 

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The gauge I'm talking about sometime comes up on my searches on ebay, like these. The bolts go back in with no change.

DIGITAL TEMPERATURE GAUGE, ENGINE ALARM, RACING OVERHEAT MONITOR TM1 | eBay

ENGINE GUARD EG01/1 Temperature Alarm- Single Sensor, Buzzer, Digital Display | eBay

The ideal would be to somehow adapt the oil level sensor from another vehicle.

Hopefully I've given you some helpful ideas. Thanks to you next time I have my engine shields off I'm gonna check those hoses. Might even invest in one of those gauges above myself thinking about it.
 

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1999 Toyota RAV4 with 3MZ-FE 6 cylinder engine, camo wrap, OME lift, heavily modded
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Discussion Starter #7 (Edited)
I liked it! I'll have to see if I can find one in the states, shipping from Australia is crazy expensive. Never mind, free shipping! This will be on my must have list for my next mods.
 
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