temp gauge probe on A343F tranny

drexx

drexx

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30Oct2003 (UTC -7)

I almost purchased Auto Meter transmission temp gauge (p/n 2640; see http://www.autometer.com/hp/2003_catalog/street_performance/41.html), but self-doubt overtook me.

Where will I drill the hole in the A343F auto tranny? Just beside the stock temp gauge proble? Or is there any way I can just use the factory temp gauge (which is what I really would like instead) ?

Thanks in advance! BTW, this is for my 2001 UZJ-100.
 
cruiserdan

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Does Autometer state a recommended location for the probe?
It would be fairly easy to drop the pan and install it in the pan. I don't know how accurate the reading would be.
 
drexx

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30Oct2003 (UTC -7)

[quote author=cruiserdan link=board=2;threadid=6944;start=msg57286#msg57286 date=1067578122]
Does Autometer state a recommended location for the probe?
It would be fairly easy to drop the pan and install it in the pan. I don't know how accurate the reading would be.
[/quote]

The online instructions from www.autometer.com only advices about how to drill and screw on the probe properly. It's not helpful at all. :(
 
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yomama

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I connected mine off the ECU. Thereby using the sensor built in. As you asked if it was possible.

Yomama
 
drexx

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31Oct2003 (UTC -7)

[quote author=yomama link=board=2;threadid=6944;start=msg57340#msg57340 date=1067610728]
I connected mine off the ECU. Thereby using the sensor built in. As you asked if it was possible.

Yomama
[/quote]

If you can be so kind, can you give me more details please? That idea is new to me...
 
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yomama

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I don't recall which wires I taped into. You need the electical manual to figure out which connector to tap into. If you plan on keeping the Cruiser for a few years and playing with it in such a way I would highly recommend getting one. I have about five logs in the fire right now and will probably not have time to look it up for you for at least a couple weeks.

Yomama
 
Photoman

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I don't know if this will help you or not but mine is going in the trans pan.
Bill
 
R

Rich

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It may not be common knowledge, but temp sensors are available in sizes / threading to replace the usual drain plugs. It is the easiest way to install a sensor and measuring temps from the sump is the most common approach. What you really want to know is whether or not your tranny cooling system is keeping up with the heat load. Sensor in the sump will provide that info.

Rich
 
drexx

drexx

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01Nov2003 (UTC -7)

Thanks guys. So I just checked the Toyota Repair & Electrical Manuals. The schematic says I should look for a Brown-White and Blue-White wires connected to the "A/T Oil Temp Sensor". It's a resistor that gives off 12.1 kOhms when 20 C (68 F) cold, to 780 Ohms when 110 C (230 F) hot.

Should I just splice and solder with these two wires to the electrical Autometer tranny temp gauge?
 
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[quote author=drexx link=board=2;threadid=6944;start=msg57750#msg57750 date=1067674882]
01Nov2003 (UTC -7)

Thanks guys. So I just checked the Toyota Repair & Electrical Manuals. The schematic says I should look for a Brown-White and Blue-White wires connected to the "A/T Oil Temp Sensor". It's a resistor that gives off 12.1 kOhms when 20 C (68 F) cold, to 780 Ohms when 110 C (230 F) hot.

Should I just splice and solder with these two wires to the electrical Autometer tranny temp gauge?
[/quote]

I claim no expertise with this cirucit, but if you are talking about leaving the factory sensor connected to the ecu while splicing in a connection to a new meter I would wonder how that would "net out". Your aftermarket meter will be sensing both the factory sensor and whatever effect the ecu has on the circuit. The ecu would likewise be sensing the factory sensor and the effect the aftermarket meter has on the circuit. Your aftermarket meter and your ecu may not like each other.

The other concern you also need to work out is whether or not your aftermarket meter is designed to work with a thermistor with the specs of the one Toyota installed that you quoted as 12.1 kOhms when 20 C (68 F) cold, to 780 Ohms when 110 C (230 F).

I would advise using a separate sensor for your aftermarket meter. My recommendation is that you get a sensor that works with your meter that fits into the tranny drain fitting. If you can't find a sensor to go there, then drop the pan and pay somebody to silver solder or braze a fitting to the pan into which you can install your sensor.

Rich
 
drexx

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01Nov2003 (UTC -7)

:doh:

Thanks Rich. You make a lot of sense... I shouldn't be thinking if it's way past my bedtime :slap:
 
drexx

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02Nov2003 (UTC -7)

[quote author=Photoman link=board=2;threadid=6944;start=msg57489#msg57489 date=1067632213]
I don't know if this will help you or not but mine is going in the trans pan.
Bill
[/quote]

Thanks Bill. I looked underneath the 'Cruiser again this morning, and saw that the Toyota temp probe is located above the tranny ATF/oil pan, at the transmission housing itself --therefore able to provide more real-time info. If I put the Auto Meter probe itself on the drain plug, will the reading be good enough? I understand that it won't give numbers as high as what the Toyota temp probe can see, as the tranny sump cools the fluid somewhat.
 
Photoman

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Drexx,
This is another one of those areas of debate and I'm sure everyone has their own opinion. My thoughts are it depends on why you want the gauge. If it is to protect the trans by knowing when to pull over and cool down, then the stock location is probably the best and I would guess approx. 215F would be your stop point. If you want to know when you may have ruined the fluid and need to change right away then you could try to hook into the hot line just after the torque converter. You could see higher temps there, say around 300F-350F and these temps could vary quickly. The pan will show lower temps but to me it is sort of relative. If I see 195F-205F in the pan I can figure maybe 215F at the stock location. My problem with the stock location is if you replace the stock probe does this throw off the computer. Tying into the existing wiring for both is an option but has the risks pointed out earlier and also as has been mentioned will the readings be correct. The drain plug adapter is an easy option and will work but carries the risk of catching on something and breaking off with perhaps the loss of fluid. Ideally, I think trans temps should be kept between 175F (so it's hot enough to do it's job) and 195F where more wear seems to start taking place. Here is a link to show trans life vrs. temps.
http://www.dieselpage.com/haydento.htm

FWIW, I am doing mine if you look at the pic for a gauge and a temp switch (two holes) so I can pull in a fan type trans cooler; so it is not as important to me to be able to see the higher temps another probe location might see. Also, again just my opinion but if you do decide to drill the pan for some bungs, I would not braze them in but weld them in as I did. I feel I can braze with the best of them, but have seen too many times brazing will crack in certain situations and I would not want to take a chance at this location. $.10 worth.
Bill
 
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landandsea

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How about looking for a brass fitting that can be installed in one of the trans fluid cooler lines. It could be a "T" that the sensor screwed into.

Hydraulic supply stores and even some hardware stores have wide selections of that kind of fitting. I have found that if you go to a good one and tell them exactly what you are trying to accomplish, they will go to the bins and come back with just the right setup.

You just have to find the Cdan of the brass fitting world.

Ed
 

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