Transmission Cooler

[MountainManJoe]

Your 2000 should already have a trans temp sensor. I read mine using a Scanguage2.

[Rileysowner]

Your 2000 should already have a trans temp sensor. I read mine using a Scanguage2.

I'm not sure, but I would guess any of the vans with the E version of the 4L60 would have a temp sensor as I seem to remember reading the way the trans routes fluid it dependent on the computer reading the temp. I am not sure on that, a certain answer would be good to have.

[Lumpy]

Your 2000 should already have a trans temp sensor. I read mine using a Scanguage2.

I'm not sure, but I would guess any of the vans with the E version of the 4L60 would have a temp sensor as I seem to remember reading the way the trans routes fluid it dependent on the computer reading the temp. I am not sure on that, a certain answer would be good to have.

You'd no doubt still need a dedicated sensor for the gauge you install. You surely won't be able to use the existing one for both the gauge and the ECM. The sensor will come with the gauge. Installing the gauge temp sensor is easier than changing wiper blades. Unscrew a bolt, screw in the sensor. Driver side of the transmission, above the shift linkage.


Lump

[Rileysowner]

True, a dedicated sensor would be needed, but having the sensor for the ECM allows a person to use a scan-gauge and not have to run wires like I am right now. Not that running wires is that difficult, but it can be annoying, at least I find it so.

[LaGrasta]

I just returned from a 900 mile round trip from SoCal to Yosemite. My '98 with 156k ran up and back without a hitch.
Flat ground running, the engine ran at about 165° and the tranny just slightly higher.
However the moment we climbed, the tranny increased as much as 230° while the engine, even under this load never got higher than 200°.

ambient temp: approx 105°
gear selection when climbing: 3rd to avoid torque converter slipping in and out of overdrive when on mountain roads.
temp gauge port: 4L60e test port. I'm still not clear if this is measuring fluid or case temps.

From what I read, anything over 200° is bad for the trans however it shifted great and has 156k so what gives? Forgive me, I know I've brought this up before, but after this trip, I'm still not satisfied with my readings.

[Lumpy]

I just returned from a 900 mile round trip from SoCal to Yosemite. My '98 with 156k ran up and back without a hitch.
Flat ground running, the engine ran at about 165° and the tranny just slightly higher.
However the moment we climbed, the tranny increased as much as 230° while the engine, even under this load never got higher than 200°.

ambient temp: approx 105°
gear selection when climbing: 3rd to avoid torque converter slipping in and out of overdrive when on mountain roads.
temp gauge port: 4L60e test port. I'm still not clear if this is measuring fluid or case temps.

From what I read, anything over 200° is bad for the trans however it shifted great and has 156k so what gives? Forgive me, I know I've brought this up before, but after this trip, I'm still not satisfied with my readings.

My temp sensor is in the same place yours is. So whatever it's reading (case or fluid) it's the same as yours. Driving around town (no highway), no hills or mountains, in current Phoenix temps (110 degrees day/100 night) my trans temp has not gone above 160. I allow the trans to shift into whatever gear it wants to.

89 Astro, aux trans cooler, 290,000 on the trans, 10K on the engine, sensor in the 700r4 test port, Amsoil synthetic cherry juice.

Don't know if that will do anything to help you diagnose your high temps.
But perhaps it will help establish a baseline of what might be normal.

Lumpy

[LaGrasta]

thanks Lumpy!

[LiftedAWDAstro]

I just returned from a 900 mile round trip from SoCal to Yosemite. My '98 with 156k ran up and back without a hitch.
Flat ground running, the engine ran at about 165° and the tranny just slightly higher.
However the moment we climbed, the tranny increased as much as 230° while the engine, even under this load never got higher than 200°.

How are you measuring the engine temp? Are you going by the dash gauge? If so I think if you could scan the ECM you will see the engine coolant temp is hovering around 195* (provided you have the 195 stat). If this is the case, as it is with the SPB (I paid to have it scanned to be sure), You would see climbing engine temps of around 230*.

ambient temp: approx 105°
gear selection when climbing: 3rd to avoid torque converter slipping in and out of overdrive when on mountain roads.
temp gauge port: 4L60e test port. I'm still not clear if this is measuring fluid or case temps.

From what I read, anything over 200° is bad for the trans however it shifted great and has 156k so what gives? Forgive me, I know I've brought this up before, but after this trip, I'm still not satisfied with my readings.

The sensor in the test port is actually measuring case temps as I don't think the sensor sticks in far enough to get in the fluid stream 100% If you are running synthetic fluid, occasional temps up to about 250* are acceptable. As long as you let off the gas to keep it in check you will be fine. Due to your trans having 156k miles it is worn enough that the bands are slipping more than when new so you will see higher temps. You could always add a 12" aux fan in front of the trans cooler just for those mountain climbs.

[batmo]

wow thats alot of miles on an auto trrans Lumpy! Ive never managed to get past the 200k mark on one but I tow alot and never used a temp guage until this one I have now.

good info Lifted, my 700r4 gets up to 250 while towing and going up a long mountain. thats with synthetic fluid, two coolers and elec.fan.

Ive had some concern about it but it only gets this high when towing up big mountains on hot days.

BTW Ive been told that if you use the test port for your sender you will have higher than normal readings because the fluid is pressurized there and the pressure slightly increasses the temp. not certain that is true but it does make sense.

[LaGrasta]

Sounds like my readings are the same as most of yours and my suspicion of the port temp is true too. I guess I'll just keep driving and not worry about any of it. Thanks for your input.

[Lumpy]

...my 700r4 gets up to 250 while towing and going up a long mountain. thats with synthetic fluid, two coolers and elec.fan...

Where is your temp sensor, Batmo? Test port?
Or are you talking about water temp?

Lump

[Cobra]

i finally got it installed the other day and today i was talking to my boss about it he has the same engine and transmission in his jimmy(2002? i think) does it have the same cooler setup if so wouldn't also be a good idea to put one on it?

[kings-x59]

wow thats alot of miles on an auto trrans Lumpy! Ive never managed to get past the 200k mark on one but I tow alot and never used a temp guage until this one I have now.

good info Lifted, my 700r4 gets up to 250 while towing and going up a long mountain. thats with synthetic fluid, two coolers and elec.fan.

Ive had some concern about it but it only gets this high when towing up big mountains on hot days.

BTW Ive been told that if you use the test port for your sender you will have higher than normal readings because the fluid is pressurized there and the pressure slightly increasses the temp. not certain that is true but it does make sense.

250? holey moley, what are your rear end gears?

[LaGrasta]

i finally got it installed the other day and today i was talking to my boss about it he has the same engine and transmission in his jimmy(2002? i think) does it have the same cooler setup if so wouldn't also be a good idea to put one on it?

Yeah, sure. I helped install one exactly the same way in my friend's 1997 Suburban. Works just the same with the same readings/results.

[MountainManJoe]

For my AWD 2003 Astro, I think I will go with a Tru-Cool LPD4590 kit. I have a ScanGaugeII, which gets the trans temp from the OBDII serial data. Seems to work fine, but I don't know where in the fluid stream the temperature is measured.

I am told that the TFP Valve Position Switch located in the valve body has a thermistor. I think that means it's measuring pan fluid temperature right after its drawn up through the filter.

I think I'll put the cooler in series with the OEM radiator heat exchanger, and I haven't decided before or after.

Sorry to resurrect such an old post, but it made me think of something. What if you were to put a 'T' in the transmission lines, and run the aux cooler in PARALLEL, rather than series? The fluid would experience a shorter path and better flow. Additionally, if you included valves in the 'T', you could control the flow. Turn off the aux in the winter for example.

I've got my tranny cooler mounted... Removing the grill was very easy once I found the correct tool.

Does this grill have something other than a basic bolt?