4l80 overheating…maybe
Thread Starter
Teching In
Joined: Dec 2019
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From: Md
4l80 overheating…maybe So I regrouped and I’m gonna give this a try from a different approach.
I just recently had my converter rebuilt(around 3500 stall) and transmission gone through after the tcc burned up.
The transmission fluid is still getting hot. Creeps up normally until about 180 then just takes off from there.
-Cooler is a tru cool h7b 29k btu but I just hooked up the stock cooler as well and seems to have helped a bit
- tcc slip for example in 4th unlocked averages around 400 rpm. 0 when locked
-there are a bunch of black chunks in the fluid(same as before when the tcc broke)
Even though I flushed the cooler and lines I suppose I could have done a poor job and the black stuff is residual from before or it’s new.
So should I have the tranny flushed and see if I can get the fluid cleaned up and see if that helps or is a flush too risky?
Assuming everything is working properly, is this cooler setup just not sufficient? I mean just cruising with converter locked in a 40 degree day it overheats.
Is that too much tcc slip? I haven’t been able to find and hard numbers on what is acceptable
thanks for any help
I just recently had my converter rebuilt(around 3500 stall) and transmission gone through after the tcc burned up.
The transmission fluid is still getting hot. Creeps up normally until about 180 then just takes off from there.
-Cooler is a tru cool h7b 29k btu but I just hooked up the stock cooler as well and seems to have helped a bit
- tcc slip for example in 4th unlocked averages around 400 rpm. 0 when locked
-there are a bunch of black chunks in the fluid(same as before when the tcc broke)
Even though I flushed the cooler and lines I suppose I could have done a poor job and the black stuff is residual from before or it’s new.
So should I have the tranny flushed and see if I can get the fluid cleaned up and see if that helps or is a flush too risky?
Assuming everything is working properly, is this cooler setup just not sufficient? I mean just cruising with converter locked in a 40 degree day it overheats.
Is that too much tcc slip? I haven’t been able to find and hard numbers on what is acceptable
thanks for any help
Last edited by Rsoup; Mar 9, 2022 at 02:10 PM. Reason: New questions
how hot is what you consider too hot? i'm good with 180
29k is on the small side. i usually recommend the 40k to customers.
oof yeah not adequately flushing the cooler is a bummer
29k is on the small side. i usually recommend the 40k to customers.
oof yeah not adequately flushing the cooler is a bummer
Thread Starter
Teching In
Joined: Dec 2019
Posts: 37
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From: Md
Actually I just double checked and it’s the m7b not the h7b so it’s only 20k btu. The best cooler I can fit bc of the intercooler is the derale 1000 series 19 row stacked plate(37k btu) so I’m just gonna get it flushed and then install the new cooler and pray for the best!
Thread Starter
Teching In
Joined: Dec 2019
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From: Md
Does anyone know the ideal coolant flow rate for the 4l80? I disconnected the input line and put in a bucket and started the truck as I simultaneously refilled the trans. I tool a little over a minute to fill one gallon In the bucket. I don’t even know if this is an accurate test of flow rate. I read around 3g/min is ideal but I believe that was tested when driving the vehicle. I’m going to bypass the coolers and test it again but to me the flow seems inadequate and maybe why it’s overheating.
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From: Seattle
When you had the unit gone through, can you recall the condition of the pump? Where the gears sit in the gear housing?
Thread Starter
Teching In
Joined: Dec 2019
Posts: 37
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From: Md
The only thing they said was it looked fine except for a few iffy clutches. It was rebuilt at ATI and dyno tested. I bypassed the factory cooler and got almost 2g/min of flow but still the temps just keep rising. It does take like 20-30 min of driving and now at idle in park the temps will drop. To me that suggests it’s an internal issue
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The only thing they said was it looked fine except for a few iffy clutches. It was rebuilt at ATI and dyno tested. I bypassed the factory cooler and got almost 2g/min of flow but still the temps just keep rising. It does take like 20-30 min of driving and now at idle in park the temps will drop. To me that suggests it’s an internal issue
Are you positive that your converter is locking up?
Never mind.. I missed that part
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