Lower than normal transmisson temperature?

thegipper

thegipper

New member
Many of you know that i just swapped in a used motor into my 97 SR5. The engine is running excellent and everything is working great.

One thing that I've noticed is that my tranny temp gauge (glowshift) has not moved at all (minimum of 80 degrees before it will move). I've driven it around town a bunch and even to work today, it never moved. It was fine before I swapped motors.

The first thing that came to mind was maybe one of the wires or the connector and the sensor is messed up. I checked and everything looks fine.

After a 15 minute drive, I felt the tranny pan it felt warm but not hot. I then felt the lines that feed into the transmission cooler and they felt cool, not warm at all.

I checked the fluid level and it's good. I also touched the fluid on the dipstick and it again felt cool or maybe just slightly warm.

I'm not sure how changing engines would change anything but something is going on.

It has been about 40 degrees the last few days but even when it was in the teens or lower with my old engine, the tranny temps would still register after a 15 or 20 minute drive.

Should I worry about this? Any ideas?

The tranny is working great, no problems at all...
 
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Is your torque converter locking up while you are driving? If it is then the transmission fluid is warm enough for the ecu to let it lock. if the fluid is good and at hot mark when engine is at operating temp, you are good.
 
I suspect your instrumentation is at fault. If something feels warm to your hand, it's probably warmer than body temp.
 
spartacus said:
Is your torque converter locking up while you are driving? If it is then the transmission fluid is warm enough for the ecu to let it lock. if the fluid is good and at hot mark when engine is at operating temp, you are good.
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Yup, converter locks up fine.
 
It's a bit of a pain, but I suggest taking out your sending unit from the T, and dipping it into a pot of freshly boiled water. Then see if the gauge reads more than 80F, and you'll have your answer as to whether it's the gauge or the fluid/tranny. Easy peasy.
 
I pulled the skid plate back off again today after work and double checked everything. The lines (hard or soft) are not damaged anywhere. I do not see any leaks at all and the fluid level is good.

torque converter locks up fine and everything is working fine (shifting good etc).

I used a heat gun and heated up the brass T fitting while the engine was off but the ignition was on for about a minute. I checked the gauge and it had risen to 125 degrees so I know the gauge/sensor are working fine.

That means, my transmission is not warming up past 80 degrees on a 10ish mile drive, mostly country (55mph) with a few round abouts. It's about 40 degrees today.

Before, it would have registered. Not much more than 80, probably only 110ish if that.

For whatever reason the transmission is running much cooler with this engine. Coolant temps are totally normally btw (sits between 185/190 deg).

Are there any scenarios where too cool of transmission temps would be a bad thing or the symptoms of a problem? I can't think of any...
 
thegipper said:
I pulled the skid plate back off again today after work and double checked everything. The lines (hard or soft) are not damaged anywhere. I do not see any leaks at all and the fluid level is good.

torque converter locks up fine and everything is working fine (shifting good etc).

I used a heat gun and heated up the brass T fitting while the engine was off but the ignition was on for about a minute. I checked the gauge and it had risen to 125 degrees so I know the gauge/sensor are working fine.

That means, my transmission is not warming up past 80 degrees on a 10ish mile drive, mostly country (55mph) with a few round abouts. It's about 40 degrees today.

Before, it would have registered. Not much more than 80, probably only 110ish if that.

For whatever reason the transmission is running much cooler with this engine. Coolant temps are totally normally btw (sits between 185/190 deg).

Are there any scenarios where too cool of transmission temps would be a bad thing or the symptoms of a problem? I can't think of any...
Click to expand...

Very strange on your cooling issue and it doesn't make much sense to me.

To answer your question on to low of temperature, I run a MASSIVE oil cooler and my trans temps will be <140deg on a 85*deg and maybe 120 if its 40deg out. Its been that way for 6-7yrs and I have had no issues.
 
twitchee2 said:
Very strange on your cooling issue and it doesn't make much sense to me.

To answer your question on to low of temperature, I run a MASSIVE oil cooler and my trans temps will be <140deg on a 85*deg and maybe 120 if its 40deg out. Its been that way for 6-7yrs and I have had no issues.
Click to expand...

MASSIVE transmission cooler details?
 
The only downside to cold fluid is longer shift times (it will not shift out of 1st easily if the fluid is too cold) and POTENTIALLY a risk of premature wear due to the fluid not being a low enough viscosity. However I'm no engineer so 80-90 degree fluid might still be warm enough to protect just fine.

Edited - No clue why it's so cold then.
 
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The 3rd gens have HUGE issues with the coolers built into the radiator. Bypass it completely and run an external cooler only. Search for the "pink milkshake" and you'll see why. Good way to wipe the tranny out real quick.
 
thegipper said:
I have no external tranny cooler, just to be clear.

Tranny is shifting fine, no delays or anything.
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To be clear, you want an external cooler ONLY The internal cooler is a time bomb leading up to a new transmission. Like I said, search for the pink milkshake, you'll be glad you did.
 
2016 4Runner SR5 said:
To be clear, you want an external cooler ONLY The internal cooler is a time bomb leading up to a new transmission. Like I said, search for the pink milkshake, you'll be glad you did.
Click to expand...

Been there, done that. I know the risks and choose to replace the radiator every 5 or so years. Not interested in an external cooler.

I'm looking for suggestions as to why my fluid temps seem to be much lower after swapping engines.
 
2016 4Runner SR5 said:
To be clear, you want an external cooler ONLY The internal cooler is a time bomb leading up to a new transmission. Like I said, search for the pink milkshake, you'll be glad you did.
Click to expand...

The pink milkshake is actually quite rare. Preventative maintenance is always a good thing to help correct it, some will just replace the radiator and they are good to go for another 150k-200k miles.

I know that some do use a cooler to avoid the issue, mine is entirely for heat reduction though. If your radiator shows no scaling/rust inside then your risk of the pink milkshake is very, very low.

LBJ failure though? Yeah, that one is real. Known several people personally who have had that one happen.
 
gamefreakgc said:
If your radiator shows no scaling/rust inside then your risk of the pink milkshake is very, very low.
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Bingo. Having opened up my stock radiator a year or two ago after 270k+ miles - there were no problems and no corrosion internally on the cooler. I have no fear of the pink milkshake as long as fluid changes are done regularly.

-Charlie
 
thegipper said:
I used a heat gun and heated up the brass T fitting while the engine was off but the ignition was on for about a minute. I checked the gauge and it had risen to 125 degrees so I know the gauge/sensor are working fine.
Click to expand...

Did you verify the fitting temperature with an IR gun or the like? The fact it is changing temperature is not a guarantee of accuracy especially on a sensor that works based on circuit resistance.

Maybe Ohm out the wiring between your gauge and the sensor, something may have been nicked or loosened during the swap.
 
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