Gents,

I have a tru cool cooler inline with my factory cooler on my truck. While driving around in the summer so far, my trans temp is 150-170 without a trailer, and just driving around when its 85 degrees outside. I hook up the trailer, and empty with a total weight of truck and trailer of 16k, my trans temp is 190.

This seems really high to me. Even when you are on a long stretch of road at 60 mph, the trans temp doesnt come down much, and it doesnt come down fast at all. Sometimes it takes 30 mins on the highway to drop 20 degrees.

Something seems not right. The fluid is only 6 months old, its still red, and smells like trans fluid still. I have the external trans filter installed too.

Any ideas are most appreciated.

 

Those temperatures look absolutely normal to me.

If you want to lower them, though I don't see why, get rid of the stock cooler and the tru-cool. Install a 6.0L cooler in their place. If you have a radiator cooler, keep it in the circuit.

 

Where are you reading your temps from? The test port on the side of the tranny or somewhere else? Those do seem a bit high but not out of spec in terms of what the tranny can handle. My temps are lower but I'm not running the same setup so it's not an apples to apples comparison.

 

subscribing

 

I pulled my trailer loaded at the temps went to 230 pretty quickly.

I would think with two coolers on the transmission, at least the temps would cool down a lot quicker when you finally get on the highway and get airflow moving over the coolers.

I have the temp sender plugged in the drivers side of the transmission, there is a port there that my gauge instructions said to use.

Im wondering if my bypass is plugged? Transmission has 120k on it since ive had the truck, and Im not sure how many miles before me.

Im wondering why my oil temp heats so fast. If your towing with the overdrive button pushed in and the light on on the gearshift, the trans temps get higher quicker than with the light off. I just cant tow with the od off because of high egts most of the time.

Mark, you think these are normal temps? Does the transmission run hotter with more miles on it?

Thanks for your inputs. Without a trailer, just my truck, why am I seeing 180 degrees on the trans temp when its only 80 outside? Is that high?

 

Aric,
I have the same trans cooler setup as you and see about 130-140* trans temps in 90+* ambient temps with the A/C on. 180* does seem a bit high for 80* ambient temps with that setup.

 

Thats how it feels to me too. Dunno if high mileage and major weight pulling have done their damage over time, or I've got a plugged, or semi plugged bypass. Temps get hot fast when towing though.

One thing I noticed, in reverse sometimes, you push the gas pedal, and nothing happens. Push it a couple more times, and then things are normal. Wonder what that means?

 

I'm wondering too why your temps are that high, Tru-Cool advertises or says a 40* drop in temps, or something of that nature..Theres more Tru-Cool users that will chime in there thoughts along with the guys above.

 

not much time spent with tranny gauge here, but just got back from camping with the 12ft camper weight totalling 13K and tranny gauge up hills went to 180. Kept the speed at 50 going uphills and it dropped to 170. Seemed to get the tranny temp lower when RPM is a bit higher and EGT at 1000.

 

230 it pretty high. Like Mark said the temps in your first post seemed closer to the normal range. But 230 in your last post is higher than I have experienced. Unloaded I will ussually see 70-80 degrees abouve Outside Air Temps (OAT). so at 85 deg F OAT 150-170 tranny temps are in the normal range. You also need to keep in mind that while the TC is unlocked (i.e. driving around town) the TC will produce alot more heat than when it is locked.

Towing our 32' 5th wheel (10,000 lbs) I will see trans temps about 80-100 degrees above OAT depending on terrain and speed.

I would recommend dumping the fluid out of the pan and drop the tranny pan for a quick inspection. If you see some metal fragments in there I would get it checked out.

 

Trans slippage can heat up th trans fluid also. I didn't realize how much I had (gradual effect) until I rebuilt mine a short time ago. My mpgs picked up also. I recently checked the trans slippage with my AE after the rebuild and only saw a 0-4 rpm difference between the input and output speed sensors in the trans when the TC is locked. I hadn't check the rpm difference before. It is a good way to check the health of your trans.

 

Also, remove the external filter and see what is inside. I have had a Torque Converter go before and the tranny temps spiked pretty high since the TC sent the junk downrange and clogged the coolers.

 

Hmm, didn't know this - I need to check this out the next time I hook up the AE.

Thanks Roland!

 

Are you guys using the Tru Cool 4739, the 40,000 GVW one?

 

6.0L tranny cooler for me.