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Engine & DrivetrainDiscussions about the engine and drivetrain of your vehicle.
This is a discussion thread titled "What should transmission oil temp be?", within the Engine & Drivetrain forum, part of the Technical & Vehicle Assistance Forums category.
just upgraded to a new 27' trailer that weighs 5020 lbs dry. I switched to synthetic oils for all the gears and engine and has a transmission temp. gauge installed.
I went out on the first trip with the trailer last weekend. I figure my '02 Tundra (V8) was pulling well over 6,000 lbs. Even on the long hills at over 4,200 rpm's the temperature never registered on the gauge. The lowest reading on the gauge is 100 deg. and the needle never moved.
I called the installer and he said this is normal. He said it shouldn't register unless it was overheating. He said these transmissions run pretty cool even up the hills pulling a trlr.
How hot does the trans fluid get???
Thanks in advance!
john
just upgraded to a new 27' trailer that weighs 5020 lbs dry. I switched to synthetic oils for all the gears and engine and has a transmission temp. gauge installed.
I went out on the first trip with the trailer last weekend. I figure my '02 Tundra (V8) was pulling well over 6,000 lbs. Even on the long hills at over 4,200 rpm's the temperature never registered on the gauge. The lowest reading on the gauge is 100 deg. and the needle never moved.
I called the installer and he said this is normal. He said it shouldn't register unless it was overheating. He said these transmissions run pretty cool even up the hills pulling a trlr.
How hot does the trans fluid get???
Thanks in advance!
john
It depends on where the temp is measured...output to cooler will be highest; return from cooler or pan is cooler. My tranny temp sensor is in the pan, which is probably the most accurate, most meaningful, and least subject to "spikes".. What I've seen over the past year (at highway speed):
Non towing: temp will be about 40 degrees over air temp (e.g. air temp of 70 means trans temp of about 110; air temp of 90 means trans temp of about 130. Temp measured with torque converter clutch locked.
Towing: Temp about 60 degrees over air temp on level roads (e.g. air temp of 90 means trans temp of 150). On grades where the engine is working pretty hard but the torque converter clutch does NOT unlock, the trans temp will climb to about 75 degrees over air (e.g. air temp of 90 means trans temp of 165). On long hard climbs with the TC clutch unlocked (engine at WOT in 2nd gear), the trans temp will steadily climb well above these numbers. The highest trans temp I've seen so far was 195 degrees at the crest of a 5 mile long, 6% grade with 95 degree temps. I've seen temps of 180 to 185 multiple times after 8 to 10 mile climbs on 7% grades where the air temp was more like 60 degrees.
Unless you've got one heckuva aftermarket transmission cooler, your installer is feeding you a line of B.S....and he did a crappy job of installing the trans temp sensor (it may not be properly grounded). You should be seeing temperatures similar to mine...maybe higher if the sensor is in the output line from transmission to the cooler. IIRC, member Herbicidal has his tranny temp gauge sensor in that line and he was seeing temps of around 210 degrees on steep grades with air temp around 100.
Yes, these transmissions (even with the stock cooler) run fairly cool by comparison to other transmissions but "cool" is 150 degrees when towing and not 100 degrees. The only time I see my trans temp close to 100 when at highway speed is in the winter with the air temperature at or below freezing.
Your temp gauge is reading so far below true temperature that it's of no practical use at this time.
__________________ Ray
Natural White '03 Access Cab V8 SR5 4X4 with TRD Off Road Suspension, Limited Slip Differential, and Towing Package
Towing & Performance Mods: JBA Headers, Gibson Muffler, 4.30 gears, Michelin LTX M/S Tires, Hellwig Anti-Roll bar, Prodigy Trailer Brake Controller, Autometer Z-Series Transmission Temperature Gauge, Magnefine Transmission Filter
Utility & Misc Mods: Genuine Toyota OEM Step (Nerf) bars, Peragon Tonneau Cover, TracRac Rack and Rail System, Muth Signal Mirrors, Pop&Lock tailgate lock, TruSpeed speedometer calibrator, "$20" RS-3200 Upgrade, Auto-Dimming mirror w/ Temp and Compass, Clear/Red/Clear Taillights with Silverstar Signal bulbs, 3M Clear Bra
For what it's worth, I only have experience from "feeling" the fluid on the end of the dip stick and it has never been very warm to the touch. I was really suprised that it was as cool as it was but I have only towed for a few miles and did not check it then. I never has felt much warmer than my body temp to me.
I'm with Ray on temperatures, and the gorunding. My truck empty with some healthy right foot will see 170 degrees in town. This is registering on the guage with an ambiant temperature of around 60F.
You should see the guage move, and considerably when you're towning and on the way out of town.
I have the Cyberdyne digital transmission temp. gauge in my '03 Tundra. The nice thing about this gauge is that it records the max. and min. temp. within a given trip. I checked mine today on the way home from work, about a 72degF day, I saw a max of 140, my sensor is in the line to the radiator cooler, should be the absolute hottest point in the system. This was a roughly 20 minute drive from work to home city/hwy drive. The max. was definetly seen at the stop lights, stop signs and what not as soon as you start moving, espescially above about 30 Mph the temperature starts to drop. I have not yet towed with this gauge installed.
Yep Summit. That's where I got mine. I've got some photos in my gallery of it installed.
I will warn you there is one feature about this guage that I don't like. Below 70 deg. it scrolls "LO". This might not be a big problem if you live somewhere warm, but in my neck of the woods it gets cold in the winter and some days I could drive all the way to work and the gauge scrolls "LO" the whole way. That is actually why I moved the temp sensor from after both coolers to before both coolers. Now it will actually start to show a reading much sooner. I was actually considering taking it out and putting in the Autometer Z series, like most people are installing in the Tundra. There are other options, such as put in a switch to simply turn the gauge off, the only time you would need to really watch it is when towing or when hauling, driving in hilly areas, off road, etc.
Hi everyone Nice post about the Engine & Drivetrain.....Unless you've got one heckuva aftermarket transmission cooler, your installer is feeding you a line of B.S....and he did a crappy job of installing the trans temp sensor......Thanks for your posting.....
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What should transmission oil temp be?
Linear Mode
