transmission temp gauge
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From: St Augustine,Fl,USA
transmission temp gauge
I am in the process of installing a trans temp gauge and need to find a hot 12v wire to tap into this is on a 2000 f-250 can any one give me some guidance:
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Joined: Mar 2001
Posts: 4,506
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From: Puyallup, WA
You will want one that cuts the power off when the ignition is off.
On my 97, there is a 5 amp fuse slot and it has a metal tab on it. It just so happened that this fuse had no power when the ignition was off.
I simply got a flat wire connector and slipped it on the tab. Wired it to my gauges (water and trans) and added a 3 amp inline fuse just for added protection.
The same fuse also powers my radar detector wire that I have routed up and around the window frame to where it's mounted just above the rear view mirror.
I added the ground wires to the same mounting spot under the dash where there were other stock ground wires attached. (Big green hex head screw.)
In the 4+ years I've had it wired this way, no problems.....
For the illumination lights on the gauges, I found a wire from the light switch that turned on when the lights were turned on. I added a 3 amp inline fuse to this as well. In hindsight, I should have tapped into one of the dash light wires, so that the gauges would dim with the dimmer switch..... I've been meaning to change that, but just have not gotten back in there to do that......
Good luck!
Mitch
On my 97, there is a 5 amp fuse slot and it has a metal tab on it. It just so happened that this fuse had no power when the ignition was off.
I simply got a flat wire connector and slipped it on the tab. Wired it to my gauges (water and trans) and added a 3 amp inline fuse just for added protection.
The same fuse also powers my radar detector wire that I have routed up and around the window frame to where it's mounted just above the rear view mirror.
I added the ground wires to the same mounting spot under the dash where there were other stock ground wires attached. (Big green hex head screw.)
In the 4+ years I've had it wired this way, no problems.....
For the illumination lights on the gauges, I found a wire from the light switch that turned on when the lights were turned on. I added a 3 amp inline fuse to this as well. In hindsight, I should have tapped into one of the dash light wires, so that the gauges would dim with the dimmer switch..... I've been meaning to change that, but just have not gotten back in there to do that......
Good luck!
Mitch
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Joined: Feb 2005
Posts: 127
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From: Eastern, Washington State
Where did you mount the transmission temprature sensor? I'm thinking of tapping into one of the lines of the transmissin cooler, but I don't know which line is the input and which is the output. Or did you tap into the transmission oil pan?
On my last F150 (1998 w/4.6L) I tapped into the input line to the cooler. But this meant that I was reading the temp of the oil as it directly exited the torque converter (very hot!). So my readings always looked hot.
AutoMeter recommended that I mount it in the same place. They say "always monitor the hottest point".
Thoughts?
--
Mitch
'05 SuperCrew FX4
On my last F150 (1998 w/4.6L) I tapped into the input line to the cooler. But this meant that I was reading the temp of the oil as it directly exited the torque converter (very hot!). So my readings always looked hot.
AutoMeter recommended that I mount it in the same place. They say "always monitor the hottest point".
Thoughts?
--
Mitch
'05 SuperCrew FX4
Senior Member
Joined: Mar 2001
Posts: 4,506
Likes: 6
From: Puyallup, WA
Hey Mitch,
I put it in the trans output line just before it goes into the rad cooler. I tapped into the rubber hose part of the line using a brass "T" and other rubber hose related parts. I also used a length of trans line hose to form a 'loop' to complete the connection.
I like the hottest point because this tells me the max temp the fluid is getting. Since the fluid does have a temp that it will start to deteriorate, and the fluid is part of the transmission, I just like to know how hot it's getting.
You are correct in that the TC does generate most of the heat, but the TC is part of the trans too, so why not know what it's doing too?
You can agrue either side of where to put it, and both have valid points... I don't think there is a 'right or wrong' place to put the sensor, but you just have to interpret the readings according to where you did put the sensor....
IMO, the TC only unlocks for short periods of time anyway. Yes, the temp rises when it's unlocked, but I like to know that, so that I can adjust my driving to get it to lock again ASAP.
In summer time towing, my temps usually stay at around 180* for the most part. Cooler in the winter time. The most it's ever gotten to was 210* and that was only for a few minutes while climbing a grade and the TC had not locked yet. It has gotten that high in stop and go traffic too, but once I got moving again, it would go down again.
To me, those temps are normal and since it's the temp before it goes into any cooler, what goes back to the trans is going to be cooler anyway, so that's even better. Since I know the max temp, and as long as it's less then 220*, it does not really matter to me what the pan temp is because it's not going to be any hotter, that's for sure.
I just took a trip over to Wenatchee this past weekend going over I90 and up 97. Lots of grades and while the outside temps were only in the upper 50's-60's, the most the trans temp got was 180*.... When I've taken the same route in August, the temp was a steady 180* and that's the trip it got to 210* for a short period of time....
Also lets you know how hot the fluid is getting while backing up too.... That's the time it goes up pretty fast too..... Since the trans does not know where you have a sensor, the fluid is going to get as hot as it's going to get, so might as well know what that temp is, right??
Anyway, just a personal preference. I'm sure someone can come up with as many valid points for the pan or test port location too....
Mitch
I put it in the trans output line just before it goes into the rad cooler. I tapped into the rubber hose part of the line using a brass "T" and other rubber hose related parts. I also used a length of trans line hose to form a 'loop' to complete the connection.
I like the hottest point because this tells me the max temp the fluid is getting. Since the fluid does have a temp that it will start to deteriorate, and the fluid is part of the transmission, I just like to know how hot it's getting.
You are correct in that the TC does generate most of the heat, but the TC is part of the trans too, so why not know what it's doing too?
You can agrue either side of where to put it, and both have valid points... I don't think there is a 'right or wrong' place to put the sensor, but you just have to interpret the readings according to where you did put the sensor....
IMO, the TC only unlocks for short periods of time anyway. Yes, the temp rises when it's unlocked, but I like to know that, so that I can adjust my driving to get it to lock again ASAP.
In summer time towing, my temps usually stay at around 180* for the most part. Cooler in the winter time. The most it's ever gotten to was 210* and that was only for a few minutes while climbing a grade and the TC had not locked yet. It has gotten that high in stop and go traffic too, but once I got moving again, it would go down again.
To me, those temps are normal and since it's the temp before it goes into any cooler, what goes back to the trans is going to be cooler anyway, so that's even better. Since I know the max temp, and as long as it's less then 220*, it does not really matter to me what the pan temp is because it's not going to be any hotter, that's for sure.
I just took a trip over to Wenatchee this past weekend going over I90 and up 97. Lots of grades and while the outside temps were only in the upper 50's-60's, the most the trans temp got was 180*.... When I've taken the same route in August, the temp was a steady 180* and that's the trip it got to 210* for a short period of time....
Also lets you know how hot the fluid is getting while backing up too.... That's the time it goes up pretty fast too..... Since the trans does not know where you have a sensor, the fluid is going to get as hot as it's going to get, so might as well know what that temp is, right??
Anyway, just a personal preference. I'm sure someone can come up with as many valid points for the pan or test port location too....
Mitch
Last edited by MitchF150; May 24, 2005 at 01:21 PM.
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Joined: Feb 2005
Posts: 127
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From: Eastern, Washington State
Wow!! Great info Mitch. You made me realize I screwed up. I ordered the AutoMeter "Temp Manifold" that requires you to cut one of the hard lines and splice in their manifold. It has an in/out and a third threaded hole for their temp sensor. Maybe I can figure out how to make it work with a rubber line. I'd rather cut rubber lines than hard lines! 
My problem with F150's is on long steep hills. The truck won't hold 3rd gear (drive) and the TC unlocks and creates heat. The best way I could keep the tranny temp in check was to manually shift down to 2nd and run it at about 3000rpm / 50mph. This was fast enough to keep air flowing over the tranny cooler but slow enough to not over rev the motor. But on really long hills on a 100+ degree day, the temp would still climb as high as 250! It's too bad Ford didn't design 2nd gear with the TC LOCKED. Maybe our new truck will be different.
I'm hoping our new 2005 F150 with the 5.4 will be better...but then it's a 2005 SuperCrew 4x4 so it's much heavier than our old 2WD Extended Cab STX 4.6L.
I've already towed with it once and I still had to shift down to second because it wouldn't hold 3rd (steep mountain road and the curves were really tight so I had to slow down to 35 mph anyway).
I'm hoping the 2005 factory tranny cooler is better than my old aftermarket unit. We'll see!
--
Mitch
'05 SuperCrew FX4
Towing 3500lb load (Miata on aluminum car trailer)
My problem with F150's is on long steep hills. The truck won't hold 3rd gear (drive) and the TC unlocks and creates heat. The best way I could keep the tranny temp in check was to manually shift down to 2nd and run it at about 3000rpm / 50mph. This was fast enough to keep air flowing over the tranny cooler but slow enough to not over rev the motor. But on really long hills on a 100+ degree day, the temp would still climb as high as 250! It's too bad Ford didn't design 2nd gear with the TC LOCKED. Maybe our new truck will be different.
I'm hoping our new 2005 F150 with the 5.4 will be better...but then it's a 2005 SuperCrew 4x4 so it's much heavier than our old 2WD Extended Cab STX 4.6L.
I've already towed with it once and I still had to shift down to second because it wouldn't hold 3rd (steep mountain road and the curves were really tight so I had to slow down to 35 mph anyway).
I'm hoping the 2005 factory tranny cooler is better than my old aftermarket unit. We'll see!
--
Mitch
'05 SuperCrew FX4
Towing 3500lb load (Miata on aluminum car trailer)
Last edited by mitchman; May 24, 2005 at 05:16 PM.
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Joined: Mar 2001
Posts: 4,506
Likes: 6
From: Puyallup, WA
Mitch,
My TC will lock in 2nd gear..... (e4od/4r100).
Don't fret about it going into second and revving above 3 grand.... Redline is not until over 5 grand and the computer will keep it from over revving anyway.
When I pull any type of grade that's > 4%, I bog down in third too. I let the trans downshift on it's own, then I manually pull the gear shift into second. Now, I can control my speed with the gas pedal and not have it shift back into third while still climbing the hill. (which happens when I let off some on the gas, because I'm able to gain speed in second gear.)
I like it at between 50-55 mph in second. I'm pulling around 3500 rpm's at that point. With the gear shift in second and getting your foot into the gas "should" lock the TC. It does on mine at any rate. If you bog it, that's when it'll unlock, because the engine needs the revs to maintain it's speed in whatever gear you are in.
When mine hit that 210* it was going up a good size grade that was many miles long. It was at least 90* + outside. I had the a/c cranked in the cab too.... Well, the truck downshifted into second and I moved the gear shift to 2. I was going about 50 mph, but noticed my trans temp starting to rise. When it hit over the 200* mark, that's when I realized it was still in unlocked second!! I pressed the gas pedal to the floor briefly and that's when I felt the TC lock. I was able to let off the gas some and then just cruised up the rest of the hill that way. The trans temp went down to 195* for the rest of the pull.
I've only got the stock coolers on my truck and it seems to do fine. My trailer fully loaded is about #4500.
Mitch
My TC will lock in 2nd gear.....
(e4od/4r100).Don't fret about it going into second and revving above 3 grand.... Redline is not until over 5 grand and the computer will keep it from over revving anyway.
When I pull any type of grade that's > 4%, I bog down in third too. I let the trans downshift on it's own, then I manually pull the gear shift into second. Now, I can control my speed with the gas pedal and not have it shift back into third while still climbing the hill. (which happens when I let off some on the gas, because I'm able to gain speed in second gear.)
I like it at between 50-55 mph in second. I'm pulling around 3500 rpm's at that point. With the gear shift in second and getting your foot into the gas "should" lock the TC. It does on mine at any rate. If you bog it, that's when it'll unlock, because the engine needs the revs to maintain it's speed in whatever gear you are in.
When mine hit that 210* it was going up a good size grade that was many miles long. It was at least 90* + outside. I had the a/c cranked in the cab too.... Well, the truck downshifted into second and I moved the gear shift to 2. I was going about 50 mph, but noticed my trans temp starting to rise. When it hit over the 200* mark, that's when I realized it was still in unlocked second!! I pressed the gas pedal to the floor briefly and that's when I felt the TC lock. I was able to let off the gas some and then just cruised up the rest of the hill that way. The trans temp went down to 195* for the rest of the pull.
I've only got the stock coolers on my truck and it seems to do fine. My trailer fully loaded is about #4500.
Mitch
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Joined: Feb 2005
Posts: 127
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From: Eastern, Washington State
That's good to hear that you had much better results (lower temps) with your truck....I assume with the factory tow package.
I'm crossing my fingers that my '98 STX without a tow package (I added a hitch and tranny cooler) just wasn't "setup" for towing like our new truck. I hope that's the case, 'cause I really don't want to buy a diesel. We only tow about 10 times a year and the other times we spend driving in the city....not good for a huge diesel truck.
--
Mitch
'05 SuperCrew FX4
I'm crossing my fingers that my '98 STX without a tow package (I added a hitch and tranny cooler) just wasn't "setup" for towing like our new truck. I hope that's the case, 'cause I really don't want to buy a diesel. We only tow about 10 times a year and the other times we spend driving in the city....not good for a huge diesel truck.
--
Mitch
'05 SuperCrew FX4
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From: Winchester, MA
While pulling a hill in unlocked overdrive, my tranny temp shot from 120 degrees to almost 200 in a matter of seconds. The entire hill is only about 2 miles long, but quite steep. The truck was unloaded and not towing. As sson as it leveled off the temp dropped (slower than it rose) and went back to my usual cruising temp of 120 degrees.
The reason it climbs so quickly is that my sensor is mounted in the same location as Mitch's, directionon the output line of the tranny. All of the heat generated by the unlocked converter was being measure by the tranny temp guage. I imagine that if the sensor was in the pan, I would have never seen that temp spike like that. Wonder where that spike would have been if I was towing a load?
That one expereince reassured me on the placement of the gauge sensor.
The reason it climbs so quickly is that my sensor is mounted in the same location as Mitch's, directionon the output line of the tranny. All of the heat generated by the unlocked converter was being measure by the tranny temp guage. I imagine that if the sensor was in the pan, I would have never seen that temp spike like that. Wonder where that spike would have been if I was towing a load?
That one expereince reassured me on the placement of the gauge sensor.
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Joined: Jul 2004
Posts: 6,200
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From: Easton, Pa.
Be ware of gauge accuracy!
Mine reads too high according to an infrared heat gun measureing the sensor's outside temp and correlateing it with the reading on the gauge.
The 180-210 report above is just what I see but it's to high a reading by nearly 20*.
If the sensor block is mounted back near the transmission and can 'see' the exhaust, it can add heat to the block, raising it's temp. Use a shield if there is heat gain fro the exhaust.
I have two coolers in line and don't run anything through the radiator. Reason is the cooling system runs at about 190 to 210 by it'self so no real cooling is being done to help the trans fluid, with all cooling being left to the external cooler to do the job in either case.
So far, the first cooler runs at nearly the same temp as the trans outlet temp and the second cooler runs at some 40* lower before going back to the pan.
I am still in the process of reading and mapping cooler and pan temps and seeing what the average looks like over time.
I thought I would offer some experience with research into this matter because I am concerned about trans life with the towing I do.
I use syn blend Mercon V and watch the color close.
The syn blend will take higher heat before breakdown.
Mine reads too high according to an infrared heat gun measureing the sensor's outside temp and correlateing it with the reading on the gauge.
The 180-210 report above is just what I see but it's to high a reading by nearly 20*.
If the sensor block is mounted back near the transmission and can 'see' the exhaust, it can add heat to the block, raising it's temp. Use a shield if there is heat gain fro the exhaust.
I have two coolers in line and don't run anything through the radiator. Reason is the cooling system runs at about 190 to 210 by it'self so no real cooling is being done to help the trans fluid, with all cooling being left to the external cooler to do the job in either case.
So far, the first cooler runs at nearly the same temp as the trans outlet temp and the second cooler runs at some 40* lower before going back to the pan.
I am still in the process of reading and mapping cooler and pan temps and seeing what the average looks like over time.
I thought I would offer some experience with research into this matter because I am concerned about trans life with the towing I do.
I use syn blend Mercon V and watch the color close.
The syn blend will take higher heat before breakdown.
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Joined: Aug 2004
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From: TX
I finally got around to installing the gauge; gauge is located on the removable panel that covers the top of the steering column. 2 1/8 hole and the gauge/tube/wiring fit nice; plate under gauge is made of wood since I made a bed cover from 3/8 oak (yes, it's heavy!).
Hayden (trans cooler mfg.) had a fitting kit for my truck. Take the top trans cooler line off and install the Hayden male/female fittings. I got a 3/8"
t-fitting from Lowe's along with 2- 3/8" barbed nipples and fabbed it up with the trans hose.
Adel clamps/screws hold the t-fitting down to the rad. shroud; the bourdon tube runs through the firewall plug just above the gas pedal and is zip-tied to the hoses running along the driver side of the throttle body. I took into account Bluegrass' "heat shield" recommendation and I taped-in-place 3/8 plastic looming and routed the tube away from the upper rad. hose.
Temps (not towing) have been 140 on the gauge, outside temp about 90.
Good luck with your install.
Curt
Hayden (trans cooler mfg.) had a fitting kit for my truck. Take the top trans cooler line off and install the Hayden male/female fittings. I got a 3/8"
t-fitting from Lowe's along with 2- 3/8" barbed nipples and fabbed it up with the trans hose.
Adel clamps/screws hold the t-fitting down to the rad. shroud; the bourdon tube runs through the firewall plug just above the gas pedal and is zip-tied to the hoses running along the driver side of the throttle body. I took into account Bluegrass' "heat shield" recommendation and I taped-in-place 3/8 plastic looming and routed the tube away from the upper rad. hose.
Temps (not towing) have been 140 on the gauge, outside temp about 90.
Good luck with your install.
Curt