4L80E running hot help needed

[72MARIO]

I just finished a 6.0 4l80 swap. I have a massive cooler for the trans mounted in the front of the grill. Its a 30,000 btu cooler the lines do not go thru the rad cooler . -6 AN lines with correct fittings for 2004 4l80 from transmission to cooler. They are routed away from exhaust min 5" from manifold.

I am pulling a 25' trailer approximately 4500-5000 lb. In the tune we disabled torque converter lock up until 50mph. The idea was for smooth power without locking and unlocking ... gm might have known what there doing better than me... The air tempature was 95 outside. The trans runs 160-175 towing on large grades at 65-75 mph. Tempature is provided thru the Scan Gauge 2 unit

The problem is accelerating up large hills/grades where the speed limit is 35-45 mph tempature hit 224 very briefly but was averaging 218 I should note engine tempature also went from average 194 to 215 in this situation .

Could disabling the lock up be contributing to the trans tempature rise ? Or am I just being over concerned with temps in the 220 range ?

Any help would be appreciated as we are 12 hours or so from home

Mario

[72MARIO]

This is the setup. I love the power this engine has just touch the gas and go

[72MARIO]

http://www.trucool.com/h7b




Thats the cooler

[Big Port Jimmy 6]

Firstly, Sweet Bus, makes me miss my 71. Convertor slip will add heat. Shoot a PM to Clinebarger. He is the goto trans guy here.

[ls1nova71]

As stated above, Cline would know for sure, but to me it sounds like youre being a little paranoid about it. New trucks have trans coolers in the radiator so the fluid is going to be close to the engine coolant temperature which 220 isnt hot, since the factory settings for the fans is about that.

[clinebarger]

While Big Port Jimmy is correct that converter slip is most likely what caused the spike in temperature.
And ls1nova is also correct that 224 degrees is not hot enough to cause damage, But that is about the MAXIMUM you ever what to see!

However, At 224.....Things can quickly spiral out of control pulling up a long grade with the converter unlocked, If you were in Texas pulling big grades in the summer......You would have been in trouble, Not that we have big grade's in Texas

It would have been ideal for you to be in 3rd gear with the converter locked at 35-45 MPH, In Tow/Haul mode (Depending on programming) the PCM will lock the converter clutch in 2nd, 3rd, & 4th, You only need torque multiplication to get the load moving, Using it (Unlocked) after that..... Your just building heat.

The 224 pan fluid temps your reading are only part of the equation, Your trans cooler outlet temps were in the 350-400 degree range, Dexron 3 fluids can have quite a range when "Flash Point" is concerned. But 500 degrees is a general rule where the fluid starts to vaporize.
Unfortunately, Monitoring pan fluid temps doesn't warn you in time, Especially when using such a big efficient cooler like yours.

[72MARIO]

Well i had tune fixed to include factory lovk up settings. The temperature still hot 230 was the max climbing a grade in 3rd. I was pushing it hard in nearly 95 degrees. The lock up definitely helps cool it faster but it pulled much nicer with out lock up.

[clinebarger]

Any modifications to Trans pressure in the Tune?

[72MARIO]

Yes i believe 10% above stock does 96 sound right ? I might be able to share a copy of the tune with you. If it will help. I was pulling some very long grades at speeds under 45mph when the tempature spikes. We made it back home to Northern Ontario tempatures on moderate grades were at 150-60 air tempature around 75-80

[clinebarger]

Originally Posted by 72MARIO

Yes i believe 10% above stock does 96 sound right ? I might be able to share a copy of the tune with you. If it will help. I was pulling some very long grades at speeds under 45mph when the tempature spikes. We made it back home to Northern Ontario tempatures on moderate grades were at 150-60 air tempature around 75-80

What year 4L80E is this?

Without a "Lube To Line" Bypass.....Never turn the Pressure up!!!!
There 2 ways too add a Lube To Line......

1. Drill a Bypass in the Pump Cover during a rebuild.
2. Install a Sonnax lube to line Pressure Regulator Valve. Can be install with the trans in the truck.

In stock form the Pressure Regulator is biased to deliver Line Pressure Over Lubrication & Cooler Flow, At low RPM/High Demand situations.....The PR Valve can completely cut off the Cooler/Lubrication circuit.

By demanding more Line Pressure.....This is happening more frequently than GM engineers ever intended, So it is possible your pulling these grades with Little to No Cooler Flow.

As a side note, Higher Pressure equals Higher Fluid Temps, However.....With the Converter Locked & adequate Cooler Flow you should not see 230 degrees!

[truckdude239]

Any trans is going to get hot on a big hill 230 i probably wouldnt worry about as long as your not puking fuild and temps come down pretty fast when your off tbe grade

[72MARIO]

The transmission is a 2004. I will show Brian from BCO Transmissions here in Huntsville your post and see what he did to the transmission. He was hesitant to build a transmission for me knowing that the pcm had been altered from factory specs.

Thanks for your help.

[72MARIO]

I talked to Brian today and he did install a Sonnax lube to line Pressure Regulator Valve

The only other thing to do from here is to add a cooler with a thermostatatic fan. The transmission lines are about 4" away from the manifold on the inside of the frame.

Towing locally today and it didn't get over 145.