Koso water/tranny gauge install

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Rigwelder

Rigwelder

10 Year
Joined
Nov 1, 2014
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93
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Wherever the money is!
I installed a Koso water gauge about a year ago and really like it so I just got another one and installed it in the tranny line right before the radiator. The whole job is pretty straight forward as I didn't drill and tap the outlet Union like others have done, and the gauges are a simple 2 wire install. The Koso gauges actually come with a 1/8 - 28 BSP sensor but it's close enough to the NPT that with a little Teflon tape it fits just fine in a regular 1/8 fitting. Since I mounted the sensor in the tranny line I just used a brass tee with 3/8 barbs for the ends. Power comes from a mini fuse tap in place of the gauge fuse, and I grounded the gauges on the little metal support for the dash. I made a very simple gauge mount out of sheet metal that's velcroed to the dash. All in I've got about $100 into this project with both gauges and misc. wiring.

I've been very happy with the water temp gauge but will be even more at piece now being able to see the tranny temp too.

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I too have the Koso in the Coolant spot. It is like it was made for it. For $45 they are cheap insurance and piece of mind.
 
I like mine as well, just wish they came with a NPT sensor instead of the BSP but it still works so no biggie. I still might order a new outlet Union and mount the sensor there just for a cleaner install.
 
The Koso water temp gauge was the first mod I did on my 93 before I left on my trip back from LA. Not a chance I was driving a 1FZ-FE without one.

I'm not well versed on the necessity of the tranny temp though. What is the big concern? Is it more so at altitude, climbing hills?
 
I've only had about an hour or so to drive around after the tranny gauge install but it seems that my trans run a lot cooler than what other are posting on here. Last night it was only 60 outside and I saw a max temp of 145 in town then it dropped to 110 once I got on the highway. Today it's 72 out and I saw 158 around town and 120-130 at 55mph or above. Is there anything wrong with that or do these transmissions take awhile to warmup? Both trips were only about 30 minutes each.
 
I've got a koso on the coolant, love the gauge. Wish it had an audible alarm thought.

I also purchased a digital gauge and fan controller for my transmission, it reads the temp just fine but the Chinese piece of crap doesn't send the right signal voltage so its useless as a fan controller. Will replace with a koso unit.
 
What is you tranny normal operating temp with the sensor in that location? I have a sensor in the pan of one of my 80's and it reads between 140 and 170 most of the time but usually much closer to 140 unless I'm crawling the Rubicon on warm summer day.
 
mine hovers around 150 (measured at the output line to the trans cooler, the radiator trans fluid heat exchange has been bypassed.) Highest I've seen was 195 that was foot down going over vail pass fully loaded.
 
baldilocks said:
What is you tranny normal operating temp with the sensor in that location? I have a sensor in the pan of one of my 80's and it reads between 140 and 170 most of the time but usually much closer to 140 unless I'm crawling the Rubicon on warm summer day.
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So far I've only seen a max of 145 then it drops between 110-130 on the highway, is that normal? Or could the temp drop that much from the outlet Union to the rubber line? Seems like my rig just runs cool in general, even in the Rockies last fall I never saw the water temp hit 200. I'm in northern MN most of the time if that makes any difference.
 
Rigwelder said:
So far I've only seen a max of 145 then it drops between 110-130 on the highway, is that normal? Or could the temp drop that much from the outlet Union to the rubber line? Seems like my rig just runs cool in general, even in the Rockies last fall I never saw the water temp hit 200. I'm in northern MN most of the time if that makes any difference.
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I'm no expert on this but it's my understanding as explained to me by Goerend transmissions, who build bullit proof diesel truck trannies, that they prefer the temp probe in the oil pan as this will indicate a good average temp.
I have the Koso water gauge and I like your idea for the tranny temp sender because it is quick and easy. I will try it and do a comparison with my experience having the sender in the oil pan of my other (deceased 80). Thanks for the write-up.
 
The A442F transmission does seem to run very cool. I rarely see above 150 on my gauge, normally its in the 120-130 range.

Having the sender in the outflow line tells me the hottest I am getting the fluid which is why I put it there. I've noticed that when the TC is unlocked in 3rd gear and I am accelerating that this is when I generate the most heat the fastest.
 
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