4l60 unlocks on longer drives (1 Viewer)
- Thread starter workingdog
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workingdog
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- #22
That's an interesting idea
workingdog
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- #24
No, it's sitting on my desk ready to go in.
There was no obvious sign of overheating, but my theory it just gets hot enough to cause the transmission to fail over several hours, rather than the heat getting catastrophically high.
There was no obvious sign of overheating, but my theory it just gets hot enough to cause the transmission to fail over several hours, rather than the heat getting catastrophically high.
workingdog
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- #25
So, the consensus is that the tranny is simply overheating. We've eliminated everything else.
There is enough cooling capacity to keep the tranny cool when driving on flat ground but a long hill like Donner pass or towing anything is enough additional load to get it to overheat. And it doesn't way overheat, just enough that after a couple of hours something fails.
It's going to get a trans temp gauge and additional tranny cooler next week.
There is enough cooling capacity to keep the tranny cool when driving on flat ground but a long hill like Donner pass or towing anything is enough additional load to get it to overheat. And it doesn't way overheat, just enough that after a couple of hours something fails.
It's going to get a trans temp gauge and additional tranny cooler next week.
I have a 4l80 that would shift through the gears fine until I would hit a hill, then it would unlock the torque converter and eventually it'd shift to 3rd. But when I'd come down the other side of the hill it'd never lock out again until I'd pull over and shut it off for a few minutes (like when filling up at a gas station). Then it'd act normal until the next time it had to kick back down and it'd do it again. Tranny guy couldn't figure it out. I bought an ACDelco electronics package for about $120 that replaced every solenoid and every other electronic gizmo in the tranny pan that could be unbolted. It's worked fine ever since... However during my sustained 3rd gear at 70 mph attempt to get back home I did fry some clutches in the trans. It's fine around town but when I'm going uphill and it unlocks or shifts down on a reasonably warm day the tranny temp gauge climbs pretty fast. If I'm towing it goes up twice as fast. Also make sure your tire size and gear ratios are correct in the computer and put the biggest cooler you can find on it.
I would still be suspicious of something causing this. Are you really adding that much additional load to max the capacity of the trans?
This one is very close to what I ran. I Loved it.
Remote Mount : 25 Row Hyper-Cool Remote Transmission Cooler Kit, -6AN
This one is very close to what I ran. I Loved it.
Remote Mount : 25 Row Hyper-Cool Remote Transmission Cooler Kit, -6AN
workingdog
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- #28
The theory is not that I'm maxing trans, but that I'm exceeding a marginal increase in the systems cooling capacity.
I had similar issues when I first got my rig running....
Tested the TPS and it was bad.
Did you ever check that? It'd be a shame if you're going through all this and it tuned out to be something simple like that.
Tested the TPS and it was bad.
Did you ever check that? It'd be a shame if you're going through all this and it tuned out to be something simple like that.
workingdog
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- #30
The guys at RPM looked at it, didn't seem to be a problem, but not sure they checked the voltage out.
workingdog
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- #31
I wanted to update this thread.
Once the trans tempt sensor was in, it was clear that overheating is an issue. The original system simply did not have enough cooling capacity (and the way the exhaust was run was contributing to the problem). Funny, that never occurred to me. I could get to 230 degrees in less than an hour of driving. The temp would hold steady for a while, but would never go down. Flat towing my Heep 40 minutes to my friends shop and it hit 230. He put two B&M coolers behind the grill with some space between them and the radiator and on the way home it stayed right at 140.
Every time I went on a multi hour drive, especially if I was towing a light load or going over Donner Pass, I was slowly cooking the transmission.
The simplest, most obvious solution - should have seen it from the very beginning.
Once the trans tempt sensor was in, it was clear that overheating is an issue. The original system simply did not have enough cooling capacity (and the way the exhaust was run was contributing to the problem). Funny, that never occurred to me. I could get to 230 degrees in less than an hour of driving. The temp would hold steady for a while, but would never go down. Flat towing my Heep 40 minutes to my friends shop and it hit 230. He put two B&M coolers behind the grill with some space between them and the radiator and on the way home it stayed right at 140.
Every time I went on a multi hour drive, especially if I was towing a light load or going over Donner Pass, I was slowly cooking the transmission.
The simplest, most obvious solution - should have seen it from the very beginning.
curious, what fan are you running?
workingdog
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- #33
Mechanical
