Trans Temp Flux in Stop&Go but stable in freeway?

[alumarine]

Your temp is too high. Where do you have the jiggle valve? Should be at the 6 o'clock position. I'm running a TAMA brand which is OEM brand made in Japan. Here's the link to it: Stant is good name also but get as close to OEM as possible.

Napa 154-2407 180° Thermostat

Trucks new to me. Will pull thermostat in the near future to check it out.
I wasn't too worried about the temp as it's rock solid.
Thanks for the fsm pic.

 

[SnowLizard]

So with the jiggle down last night and a quick drive to temp, topped off the (yes new) radiator with coolant this am, I drove for 2hrs this am, got about 1hr of dirt/off road and pushed temps...

The water is now a average 191-193... I did see 195 briefly on a long up hill from a dead stop (to 69mph)

The trans NOW sits 160-185, that long up Hill from a dead stop pegged 204 but quickly came back down to water temp in seconds...

I can now add a tranny cooler to increase cooling capacity for my az heat...

Ambient temperature today was 65-79...

Stop and Go ish traffic (best I can get sunday), tranny was 170-188... All acceptable in my opinion

THANK YOU ALL! Especially those that posted their temps

Lesson, jiggle down for my AZ heat... And summer is right around the corner and I wonder what the temps will be.

 

[SnowLizard]

final update

rush hour traffic update

in rush hour, it was probably 83 outside, water was 190 most of the time traffic was stop/go for 1hr+ (made a 1hr drive into a 2hr drive) and the trans was 160 most of the traffic!!, at higher speeds it was 170-175... .

Lesson, jiggle down

 

[jeremyc74]

Now I'm kinda curious as to what the average temps are. I'm pretty solid at 184-186° consistently.

My Installation - March 2015

• New Radiator PN# 16410-YZZAJ (OEM - ASIN)
• T-Stat PN# 154-2407 (TAMA Brand 180°)
• Toyota Anti-Freeze PN#00272-1LLAC-01 (Factory Red not Factory Pink)

Just for another data point, I'm running a Toyota OME thermostat, and I see exactly the same temps as you. I'll hit 188 sitting in traffic, but never above that. Most of the time on the interstate it will sit right on 186, and then when the torque converter unlocks it will drop to 184 for a minute. I don't have my SG set up to do transmission temp, but I would assume that's the cooler trans fluid bringing the temp down a little.

The WT in the first post was the first thing I noticed as well.

Does anyone know of a thread on how to set the SG up to see trans temps on a 2000?

 

[Rock_Rat]

Just for another data point, I'm running a Toyota OME thermostat, and I see exactly the same temps as you. I'll hit 188 sitting in traffic, but never above that. Most of the time on the interstate it will sit right on 186, and then when the torque converter unlocks it will drop to 184 for a minute. I don't have my SG set up to do transmission temp, but I would assume that's the cooler trans fluid bringing the temp down a little.

The WT in the first post was the first thing I noticed as well.

Does anyone know of a thread on how to set the SG up to see trans temps on a 2000?

Jeremy if you have the SGII with the XGauge feature you should be able to set it up fairly easy I think. Check out the link from a year ago. I attached a pdf version of the Scan Gauge Instructions.

http://www.toyota-4runner.org/3rd-gen-t4rs/105296-scangauge-question-temp.html#post2112249

Post #9 is the exact info you need. I use both the A/F and the TFT.

http://www.toyota-4runner.org/3rd-gen-t4rs/105296-scangauge-question-temp.html#post945877

 

[Unner]

My thermostat was installed wrong when I got the truck and I would see temps around 204-209*. Now with it correct I see 186-190 ish, 191 if I'm sitting in bumper to bumper traffic on I85 in Atlanta.

Transmission shouldn't feel like it is slipping at upper 100's either. Mine only gets around 200* when I'm climbing a hill and leave the OD on or going up a steep windy road at slow speeds.

 

[nevada]

does someone care to explain why having that valve on the bottom makes it run cooler?

that makes absolutely no sense.

 

[Rock_Rat]

does somewhere care to explain why having that valve on the bottom makes it run cooler?

that makes absolutely no sense.

When you find out, please let us all know! Why does the Haynes manual say place it at 12 o'clock and the FSM says 6 o'clock? We all know what it does and my only hypothetical guess is it has a tendency to stay "stuck" closed because of a pressure differential in the pipe.

The shape of the pipe creates a pressure differential before it reaches the thermostat. Because of this, the jiggle valve is less efficient at the 12 o'clock position essentially creating a hydraulic lock. If there was a straight pipe going to the thermostat It wouldn't matter. (I'm not sure about any of this...clearly hypothetical thinking).

So instead of the t-stat "cracking" at 180 it begins to "crack" at a higher temperature, let's say at 190 instead. Our temp reading at the ECU is at the hottest point coming off the engine returning to the radiator. So once it fully opens, and runs it's course, the return temperature will be upwards in the high 190's or 200's. (insert shoulder shrug emoticon here)

Hypothetical Process

• Thermostat "cracks" at 190
• Fully opens at 196 (~6* higher than cracking temperature)
• Runs through the manifold increases to 198 or higher
• Returns to the radiator 202 (this is the reading we see)
• Cools back down

Just my own thoughts. Been years since I studied Fluid Dynamics but I'm sure old Bernoulli has something to do with it.

DISCLAIMER: All of this is hypothetical. Do not quote any of this or state it as factual. Would love to hear other thoughts.

The only fact I know is the engineers at Toyota say to place the t-stat in with the jiggle valve in the 6 o'clock position at it works for me.

 

[jeremyc74]

does somewhere care to explain why having that valve on the bottom makes it run cooler?

that makes absolutely no sense.

It doesn't make any sense, but there are too many people who've experienced it for it to not be the truth.

The normal logic is to put the jiggle valve at the top, where air can get trapped. Something about the location or coolant path in this case makes it work better at the bottom, and apparently Toyota figured that out during development because they put it in the service manual. This is the only case I've ever seen where the manufacturer recommends putting it at the 6 o' clock position instead of 12, and I've wrenched on a lot of junk over the years.