$13 ATF temp "gauge"

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Thought I would share the cheap-ass idea for an ATF temp gauge that I just installed. I picked up a digital oven thermometer, removed the metal "probe" housing around the thermocouple, cut it down and sealed it up with some heat-shrink and installed it in my truck. I routed the line through the rubber boot for the gear selector, and up over the transmission, and attached the probe to the output hard line for the stock cooler. It is held on and insulated with a piece of split heater hose and a hose clamp. The display unit is sitting under my parking brake lever.

The thermometer has an audible alarm for when the temp exceeds your setting, a range of 0 - 250C (32 - 480F) and I tested it as accurate to 1 degree at freezing and boiling. It runs off of a single AAA battery :frown:

I don't know how long it will hold up in this service, but I wanted something that would allow me to compare before and after some transmission mods that are coming, so if it gives up the ghost in a couple of months, I won't mind.

So far after one city drive, temps seem to stay in the 50-60C (120-140F) range once warmed up. For comparison, the stock ATF temp light comes on at 150C, and off at 120C (300F and 250F). At those temps you are already compromising the fluid and likely the transmission.

Some pics: The thermometer, the thermocouple, the modified temp probe.
oventherm.jpg
thermocouple.jpg
tempprobe.jpg
 
Thats a good idea but you do know they already make temp gauges for an auto tranny, right? keep us posted on how it works
 
Thats a good idea but you do know they already make temp gauges for an auto tranny, right? keep us posted on how it works

Note the title of the tread ;) After splurging on an extreme valve body, cheap is good.
 
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Ingenious. I like the alarm feature. Cheap way to use thermocouple technology. Good mod for people on a real tight budget. Well done RocDoc.
 
Very clever.... Wonder if this would work for the wife's Thanksgiving Turkey ?
 
1 year later, it's still working, and still on the original battery.
 
Note the title of the tread ;) After splurging on an extreme valve body, cheap is good.

It's not splurging when buying the best brains possible for an A440F. Now take up a collection from all the 62 owners and buy Rodney's temp gauge kit so you can compare against your el cheapo thermometer and calibrate the el cheapo for them. You'd make everybody happy!
 
It's not splurging when buying the best brains possible for an A440F. Now take up a collection from all the 62 owners and buy Rodney's temp gauge kit so you can compare against your el cheapo thermometer and calibrate the el cheapo for them. You'd make everybody happy!

Saw the group buy thread, and thought for a couple minutes. If they aren't too expensive, I might go for one. But to be honest, seeing the temps I get with the aux. cooler and the extreme valvebody I'm not too concerned.
 
Like our coolant temp and oil pressure gauges, having a relative base is way better than nothing at all and now that you have some experience with your method it is probably a good way to go. See my post regarding talking to Rodney and his "mate rate" though and it may help you go whole hog on his temp gauge kit. https://forum.ih8mud.com/60-series-wagons/282632-rodney-automatic-temp-guage-group-buy.html

Saw the group buy thread, and thought for a couple minutes. If they aren't too expensive, I might go for one. But to be honest, seeing the temps I get with the aux. cooler and the extreme valvebody I'm not too concerned.
 
Saw the group buy thread, and thought for a couple minutes. If they aren't too expensive, I might go for one. But to be honest, seeing the temps I get with the aux. cooler and the extreme valvebody I'm not too concerned.

But where are you measuring the temp? Oil pan? Or tranny outlet? The former won't tell you much. The tranny outlet is the critical location, since that tells you how hot your T/C is.
 
The trans pan location tells you how cool the ATF about to be sucked into the trans to cool it, is. Converter outlet measurement only tells you how hot the converter is getting, not how hot the bands and clutches are. They are what will fail from overheating, not the converter.

The ATF is the replaceable wear item, the trans is not.

That's my take on the topic. We can debate this forever (it has been) and neither viewpoint is likely the ever convince the other of their superiority. :)
 
Right or wrong, I put my gauge sending unit in place of the stock ID10T light sending unit.
Bought a $35.00 gauge from Auto Zone
 
Thanks!!!
Being that I'm back on the road again, driving through Southern states with a temp at 100,
I was concerned about my tranny.
I did before leaving Thomasville change the fluid, clean filter, gaskets and flush.
Ordered a oven temp.
It arrived the day I was to leave.
I installed on the road.

Very simular to the one in the thread.
I did not cut the metal prob part off.
By running the prob and wire through the rubber boot, the metal prob with the 90, lined up perfectly to hose clamp it to the proper line and the 90 to shoot the wire right up the boot out of danger!

Now I read the temp and know I love my tranny!

I'm now in Moab!!!!
 
:cool:

I ended up cutting mine out when I did my engine swap back in the fall. I never saw any temps that alarmed me after installing a cooler, so it served its purpose well and I'm happy enough without it now.
 

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