2008 Trailblazer SS

[wxo]

I've read that tranny fluid temps should normally run in the 175 to 200 degree range. At 225 degrees, it's beginning to get too hot and fluid starts breaking down. 300 degrees is the point of overheating. Higher stall converters generate more heat than stock converters (which makes sense).

[ttamrettus]

My Avalanche has a temperature sensor. Every time I tow something I turn the readout on just to keep it in check.

[wxo]

My Avalanche has a temperature sensor. Every time I tow something I turn the readout on just to keep it in check.

What kind of temps are you observing, Matt?

[ttamrettus]

to be honest I don't recall. I'll record a few for you. I am thinking right around 190 - 205 pulling an s-10 up hill.

[Maverick]

For what its worth, http://www.txchange.com/heatchrt.htm This chart has been referenced on the Maverick forum. There's no indication of where the temperature is being measured. On a Ford C4, the ATF leaving the transmission on the way to the cooler is coming directly from the TQ and will be hotter than the transmission or ATF in it.

This chart, and other expert comments on ATF temps, makes me wonder if routing a the fluid thru the cooler in the radiator AND thru an add-on cooler is a good idea. Depending on the temp at the bottom of the radiator, in 200+ degree cooling systems, the in-radiator cooler might be HEATING the fluid under normal loads. Since the effects of heating are cumulative, seems like the radiator cooler could be a negative when an aux cooler is installed.

[TireSmoker]

I thought I remember seeing in the instructions to one of my trans cooler kits was to plumb it like this:

trans-output --> external cooler input
external cooler output --> radiator cooler input
radiator cooler output --> trans-input

This allows the trans fluid to be cooled by the external cooler, but keeps it at operating temp. I think this is more important in colder climates, as the caution was that you didn't want too-cold fluid, either.

With that said, I've had the cooler in my Chevelle plumbed directly to the external cooler for over 15 years with no issues, knock-on-wood.

-Dave

[wxo]

B&M SuperCooler instructions recommend the following:

"Route the transmission fluid through the stock
radiator cooler, then through the supplemental
B&M SuperCooler and then back to the
transmission. This will provide the most efficient
transmission fluid cooling system for your vehicle."

[Fred32v]

Just returned from our little road trip to Wheeling. Even at high 80’s, travelling at 70 mph, the transmission temperature was in the high 140s and low 150s unless we stopped. Starting out again the temp would be in the 160s but quickly returning to the lower numbers. Returning home, the car said outside temp was low 90s, driving along tranny was mostly high 160s. Lower speeds saw some low and mid 170s. I’ll will watch what the tranny temp looks like the next time I’m at TRP.

[Maverick]

Just returned from our little road trip to Wheeling. Even at high 80’s, travelling at 70 mph, the transmission temperature was in the high 140s and low 150s unless we stopped. Starting out again the temp would be in the 160s but quickly returning to the lower numbers. Returning home, the car said outside temp was low 90s, driving along tranny was mostly high 160s. Lower speeds saw some low and mid 170s. I’ll will watch what the tranny temp looks like the next time I’m at TRP.

Fred,

Where is your trans temp sensor? Trans pan? On the way to the cooler(s)? On the way back to the trans?

Jim

[wxo]

Thanks for the read-outs, Fred. Now we have something to compare when I get my sensor and gauge in.

[Fred32v]

How no Idea where the computer is getting that data from,
it's somewhere under there.
Sure is busy under those covers.

[wxo]

I received my replacement temperature sender from Amazon. Testing it with a hot cup of water and comparing the reading on the gauge with the reading from the temperature gun, I see that the gauge reads way high. I'm wondering if I can add resistance into the sender circuit to make the sender match the gauge. Any thoughts?

[ttamrettus]

I drove from Atlanta to Charlotte this afternoon. I had the cruise set between 65 and 75. The outside temperature was in the 90's. The trans stayed between 192 and 209. I don't know where they measure the temp.

[Maverick]

Try measureing the water temp with a thermometer. Might be more accurate than the IR thermometer.

[wxo]

Try measureing the water temp with a thermometer. Might be more accurate than the IR thermometer.

I never considered that. I always think of technology as being more accurate. Tell me your thoughts on this.