6l80e Shifting Weird
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Teching In
Joined: Aug 2018
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6l80e Shifting Weird Hey guys, I have a 5.3/6l80e in my c10. Swapped last May and mostly been ok since. Last week I saw a MAF code. Just replaced tonight. That fixed that issue. But didn’t fix the trans shifting. It randomly flare shifts in any gear. Won’t do it under WOT or almost NO throttle. Only in the normal driving range 1500-2500ish. Threw codes P0872 and P0877. Shift is delayed and flares about 500 rpm. Hits gear hard when it engages gear. Fluid is clean and full. No metallic look or burnt smell. Good color etc. very confused. Help please! Will get video tomorrow.
Find a local transmission shop familiar with these. Might need a deeper scan to see what the TCM is doing.
Also might recommend a fluid flush including trans cooler, replace filters, and verify trans temps.
These 6Lxx transmission generate more heat than the 4Lxx and also need to run cooler. So where a 4L80 might be fine running around at 170*, the 6L80 runs better in the 150-160* range.
Also might recommend a fluid flush including trans cooler, replace filters, and verify trans temps.
These 6Lxx transmission generate more heat than the 4Lxx and also need to run cooler. So where a 4L80 might be fine running around at 170*, the 6L80 runs better in the 150-160* range.
TECH Junkie
Joined: Dec 2012
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From: Iowa
With a MAF code, make sure it is corrected, code cleared, and any other codes that were set as side effects of the MAF are cleared.
Then clear the adapt values and do a quick relearn on the trans. If that doesn't clean it up...report back and we can go from there
Then clear the adapt values and do a quick relearn on the trans. If that doesn't clean it up...report back and we can go from there
Thread Starter
Teching In
Joined: Aug 2018
Posts: 23
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With a MAF code, make sure it is corrected, code cleared, and any other codes that were set as side effects of the MAF are cleared.
Then clear the adapt values and do a quick relearn on the trans. If that doesn't clean it up...report back and we can go from there
Then clear the adapt values and do a quick relearn on the trans. If that doesn't clean it up...report back and we can go from there
I cleared codes and did a relearn the other day and it started doing the same things over again. The only new code pertaining to the drivetrain is a knock sensor, which I plan to replace this weekend while I am home from school.
Thread Starter
Teching In
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So after thinking on this for several days, I drove the truck again. It has started to idle extremely rough once it is warm and comes off high idle. Also, after watching the logs on Hptuners, the pedal position signal is jumping. Even with no input, it jumps between zero and 19 percent. With part throttle constant input, it jumps 0-19-27%. I don't know what this graph is supposed to look like, but I really feel that this isnt correct and the pedal sensor maybe going out. Anyone seen this before?
Thanks in advance
Thanks in advance
Could be a throttle position sensor. Mine just went out in my 1998 Z28. Only 44K miles. It caused long extended shifts and a couple hard shifts. I only went about 2 miles with it but it was rough and idling all over. But it did throw a code for it so Im not sure if that could be your issue or not.
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Thread Starter
Teching In
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we are gonna hook it back up to another one of my friend’s laptops today and hopefully he has a lot better idea what he is looking at. I’m planning to check the plugs this afternoon but I’m not sure a misfire is the issue. When I disconnect the battery and reconnect, the idle issue goes away for a while.
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Verdad Gallardo TECH Junkie
Joined: Dec 2012
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From: Iowa
Misfires will cause all kinds of issues with any electronically controlled trans.
Look at the misfire counter on a quality scanner or on the laptop with HPtuners etc
If it's racking them up...fix that before blaming the trans
Look at the misfire counter on a quality scanner or on the laptop with HPtuners etc
If it's racking them up...fix that before blaming the trans
Thread Starter
Teching In
Joined: Aug 2018
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Yes, it did. We tweaked a few other things as well, put a little timing in it, etc. but the maf calibration was the main issue causing both the idle and the trans issues. Drove the truck about 7 hours on the highway this weekend, no issues whatsoever.