# 05 2500HD 6.0L 4L80e Transmission Overheating after this brutal Winter!



## midnightrun7

First I'd like to say hi...Newbie Here. 

I have a 2005 Chevy Silverado 2500HD 6.0L 4X4 - 4L80e Tranny w/70,000 Miles
Great Condition.

Never had a problem with this truck until this past winter, Brutal! I pulled an engine code P0894 (Component in Transmission Slipping). I dropped the pan and change the Transmission Filter and installed Dex VI about 6 quarts. Cleaned the filters in the valve body, change the TCC Solenoid that controls the Torque Converter and put it back together. It didn't help, the truck was still overheating with no load or towing and the Torque Converter wasn't locking up. It started getting hot when the weather got warmer and didn't have a problem while plowing this winter (Was very cold)

I took it to a mechanic and he installed a new Converter, I had lockup but was still getting too hot...over 250F just driving 5-6 miles or just idling in park.

I left the truck at his shop and he's supposed to work on it today. Yesterday, I went there to check a few things like the radiator, ext cooler and lines. The cooling line on the drivers side top of the radiator was very hot after driving it. The Hose (engine) next to the line was hot of course. The lines to the cooler were outside temperature, not hot at all. The line on the bottom drivers side was touchable and the line on the passenger side top and bottom weren't hot at all. Seems like fluid is getting stuck in that area and theres no circulation. Wish I had a diagram for the cooling lines of the Tranny. Anyway, I'm thinking that maybe the radiator or lines are clogged.
Maybe some torque converter material stuck in there. 
I think the lines and cooling system should have been taken care of before the TC was replaced.
Anyone have this Problem and if so what was the fix?
Thanks-


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## Whiffyspark

If it was my truck I would have replaced the trans, convertor, and flushes lines. Factory cooler gets bypassed for a new one when replacing transmission


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## dieselss

Are you talking the trans lines or the coolant lines? 
What you could do is remove the trans lines at the external cooler and blow it out and see if anything comes out.


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## midnightrun7

Transmission lines, thanks

I know I should have replaced the transmission, however, the thing was shifting perfect...except for overdrive and overheating.


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## Whiffyspark

Have someone bypass cooler and put new one in. They're cheap

Sounds like you have a plugged cooler. Exact reason I've never replaced just a convertor lol

Everything internal in that trans can be verified with a scanner and compent tech


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## midnightrun7

*Finally Getting Somewhere...*

My Mechanic bypassed the cooler and the radiator, I'm not sure which one first. I think the cooler. We ran the truck in park for about 20 minutes and drove it for about 20 miles, in traffic and side roads. The transmission temperature did not rise fast and did not exceed 220 degrees, which is still too hot on an 85 degree day. It stayed a little below 200 for longer than the past 2 months or so and no codes. Prior to this, the Temp would come closer to red-line. He's ordering a Radiator in the morning that comes with a Tranny Cooler and Oil Cooler. Hopefully this will get me below or around 150F.

Question, should I insist that my mechanic flush all the Fluid out again?? Currently I have Dex VI and Dex III in there, is Red and Not Burnt. It seems he's the type to want to save money for his customers...lol I just want it fixed rite. I figure I'm ahead of the game if my tranny holds up, so far so good and was shifting fine today.

I'll stay posted and let all you gentlemen know if it was the radiator for sure. 
Thanks for the replies.


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## Whiffyspark

I would flush it before he puts the radiator in. 

The cooler is part of the radiator


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## dieselss

Don't forget the new cooler in front of the rad too


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## midnightrun7

*I just called in...*

Whiffyspark
He mentioned that we had the pan down 3 times which is true. I took it down and replaced the filter and added about 5-6 quarts. I pulled it down a second time and changed the TCC solenoid and he pulled down the pan and checked all the solenoids and added another 6 quarts and 4-5 more with the converter. However, the first and second time the Torque Converter was not the new one. On the 2th hand now the filter in the Tranny should be catching the crap that's in there, shouldn't it ?? IDK I wish he would just do it!

dieselss
The new Radiator comes with the Oil Cooler, and Tranny Cooler.

I don't know!


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## dieselss

External cooler. In front pass side


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## Whiffyspark

Have him flush it with a trans machine. Put a new filter in after if you're worried about it. 

We never do filters just flush it. Changing the fluid in the pan doesn't do much good for all the crap in the lines and cooler


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## midnightrun7

I got the truck back. He change the Radiator (only) and used some blue coolant (Universal he said) not Dex III that looks like dirty water. I wouldn't be surprised if he kept my coolant to sell to another customer. He didn't change the passenger side external A/T cooler or blow it out, un-f*cking-believable! I have a mix of Dex III ATF and Dex VI in the system (New and Old).

The Problem was the Radiator and the Convertor. It's running at about 100 degrees above ambient temp. About 170-180F - Still too hot with no load.

First thing tomorrow I think I'm going to flush out everything, Coolant and Transmission. Take out the External Cooler and replace it. 
I just found out he doesn't have a Flush Machine. Needless to say I was very pissed. This guy won't be in business too long.

This is bitter sweet because the transmission shifts good and it's not going up to 270-280F like before. But now I need to get the Fluids flushed, I told him to change, all over again.

Do you think I should drop the pan and change the Tranny Filter again too or am I over reacting with this cluster-F*ck

Thanks for all your inputs and replies. 
N-


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## Whiffyspark

I'd have it flush. It's up to you if you want to change the filter. Can't hurt

And yeah 180 is still warm.


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## midnightrun7

Yes, I'm going to have done. 

I am so P.Off - I never told him to add that stuff. I didn't say "Please save me money and stick dirt in my radiator" Just venting, sorry!

Would you recommend taking it to a dealer?


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## Whiffyspark

midnightrun7;1810517 said:


> Yes, I'm going to have done.
> 
> I am so P.Off - I never told him to add that stuff. I didn't say "Please save me money and stick dirt in my radiator" Just venting, sorry!
> 
> Would you recommend taking it to a dealer?


No just a regular shop is fine. Even mr tire has the machines. I think it's $180 to have trans flashed. Can't remember what we charged for coolant.

I was a tech for almost 10 years.


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## Whiffyspark

And you don't actually need dex coolant. Dex is known to cause issues because it is so damn corrosive. The 3.8 engines had ALOT of problems because of dex


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## EWSplow

I realize this is an old post, but my transmission temp usually runs around 120, even plowing. It has never exceeded 150 until today while just normal driving. 
It's been running about 170. My coolant temp stays around 200, but spiked to 250 for about a minute. 
Flush the tranny? Maybe replace the cooler?
Could it be a sensor?


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## Randall Ave

Sounds like you're engine is running to hot.


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## EWSplow

Randall Ave said:


> Sounds like you're engine is running to hot.


The engine running hot came after the tranny running hot. 
Parked it for about an hour. Everything is back to normal. While I realize 180 degree tranny temp isn't that high, it's higher than what I normally experience. I'm going to keep an eye on it.
I had some concerns, because we're getting snow tonight and don't have time to do any work on it today.


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## dieselss

Have you checked the front for snow build up?
Have you checked the fluids for level and condition?
Could have just been a glitch


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## EWSplow

My first assumption was slush and snow built up and froze. I didn't wash today cause there's more snow coming. Everything was completely clear. 
I parked on some clean snow thinking there might have been a leak. Not a drop of pink.
Checked the fluid. It was full and looked and smelled like it should.
It shifts like like it always has.
Maybe there was some brief blockage that cleared itself? 
I might be overly cautious, but the last thing I need is transmission problems.


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## Mark Oomkes

Years ago we were traveling through South Dakota and ambient air temp was between 105-109. Had a bit of a headwind and towing a bumper pull travel trailer. 

I was watching the tranny temp and it kept climbing. Slowed down 5 MPH and kept going, temp dropped and never had an issue again. I believe there is some sort of thermostat in the Torqshift and it got stuck closed for whatever reason. Only time it ever happened.


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## EWSplow

Grr. Not sure if it's related, but the wye fitting on the heater hose split today as I was exiting the freeway. Fortunately, I was able to immediately pull over and let it cool down. Thankfully, I was 1/2 mile from home. 
Before that, the coolant and tranny temp stayed normal today.


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## midnight pumpkin

blow air throught the A/C condensor fins, they get plugged up with dust,dirt,debris etc. that doesn't help airflow. Also make sure the fan shroud is in place and fully intact. Do you have the Heavy duty fan clutch?


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