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I have a thread started over at HP Tuners as well, but so far haven't gotten a reply so figured I'd post here as well.
2006 2wd Silverado 5.3/4l60 (M30), mild cam, headers, no cats, tuned on dyno back in 2010 (not by me), made 318hp @ wheels. I have never had a problem with the way this truck runs, but this is the 2nd time I've blown up the trans. The day I picked up the truck from the rebuilder, the truck when stopped will hunt for idle RPM, ~500-~700 RPM. It seems to do this more when cold. One day on the way to work it did it at every stop, but on the way home it didn't do it at all. Again, I've driven this truck for over 100K miles and it's never done this before, so I have to think it has something to do with what the rebuilder did by accident or possible a faulty trans part and not the program. It will not hunt in neutral or park, but it will in reverse and of course drive, the truck appears to shift fine and there are no issues while cruising. I've searched for vacuum leaks, looked at all trans wiring, O2 sensor wires, neutral safety switch and all appears to be fine. I've got two data logs, 20210829 A doesn't show the issue but 20210830 A does. I can collect all the data in the world, but I'm not a tuner so don't know what I'm looking at so bear with me please. What it looks like to me is the timing is getting pulled for some reason, then the RPM drops, timing comes back and RPM rises. Again, I'm guessing here. Could somebody please give some guidance as to what's going on and/or some thoughts as to where I should be looking? I've always enjoyed driving this truck, but now it's driving me nuts. Thanks in advance for any help!
2nd time I've blown up the trans---COMPLETELY DUE TO----mild cam, headers, no cats, tuned
I know there are many here who worship the 4L60E trans, and there are those who build them who believe they should be worshipped.. Both are laughable.
The reality is that they are TRASH. The fact that you have blown two of them up should be telling you something.. It's not the builders fault.. It's the team of engineers who designed the trans. You can expect, and SHOULD expect that you will blow up the next trans as well.. It's the nature of the beast when running a moped transmission behind an engine that makes decent power, in a heavy truck. I know there will be many attempting to thrash me for stating the TRUTH.. But the facts bear out what I'm saying.. If the 60E were so good, why then did a measly 4.8L truck need torque management to save the transmissions life? Right... Because a bone stock 4.8, or 5.3 can SHRED a 60E in very little time if torque management is removed. Torque management was put in place to try and mitigate transmission failure. When you build more horsepower, or torque, into the vehicle, and possibly remove torque management at the same time-you are condemning the transmission to a death sentence. The only way to avoid having it die in those circumstances is to drive it very carefully. Like your grandfather would.. and never ever beat on it.. Then it may last the life of the vehicle. Or... you can believe some of the hucksters who would tell you that 4L60E's are SUPER transmissions and that they can build you one that will last forever for the measly price of your first childs soul ... Who would put $3000+ into a moped transmission? I have to tread carefully here as there are many who have.. and there are many selling the spray-painted moped transmissions who's survival depends on people buying them.
On to the important stuff.. I looked at the first log... Why does TCC APPLIED show that it is being turned on at 9MPH? If you had logged TCC slip RPM we could see if the TCC is actually being applied.. Regardless, TCC should not be applied until much higher up in the MPH range (35+). Also.. Look at your timing.. It's as low as 10 degrees at times in PARK. It was basically hovering around 15-16-17.. Even when slowing down the timing is dipping down below 20 degrees. If you watch the timing line in the graphs (WHITE line) you can clearly see a sawtooth pattern.. that saw tooth pattern is telling you that something is off.. The peaks and valleys is the engine stumbling, or struggling, to idle and the PCM is using the timing to try and correct the issue. It could be AFR is off, or a host of things.. But the timing line is trying to tell you a story. I would start by hooking up, and logging, AFR..You need to know if the AFR is DEAD NUTS on for the entire operating range. Look at 4:41 where you are just steady cruising and watch what the spark timing is doing! Based on TPS it looks like you were holding the throttle steady and yet the timing was all over the place. Even the tach needle is bouncing.. Indicating potentially an AFR that is off, and the engine is surging. OR... You have a misfire... OR... this could be a long list.
The 2nd log.. Look at how low timing is on the initial start up.. This is the PCM trying to bring the idle back down to where it is commanded.. It is pulling timing-ALL THE WAY DOWN TO ZERO-- trying to get the engine idle speed down.. Why is the engine idle speed so high? Maybe it's lean and is idling way up there and the PCM is pulling timing trying to control it. One of those items for the "or" list.. Vacuum leak. Have you smoked the engine yet looking for leaks?
Were there any codes? Have you scanned it with a REAL scanner such as a Snap-on, or Autel scanner? The plastic hand held cheapies that are less than $100 will not give you the data that you need and often will not even pull all the codes that are present. If you have not scanned it yet-do that now.
I know you said you posted on HP Tuners.. Post up a link so that anyone seeing this one, can also go over there. There are some smart guys over there. I'm betting they are going to tell you that there is much more that you need to log in order to drill down on the problem. Either way, post back and let us know what you find was the issue.
2nd time I've blown up the trans---COMPLETELY DUE TO----mild cam, headers, no cats, tuned
I know there are many here who worship the 4L60E trans, and there are those who build them who believe they should be worshipped.. Both are laughable.
Thanks for the reply! Couldn't agree more about the 60E, I thought about going 80E after this blowup but didn't have the time to do all the extra work as the truck is my daily driver. My LQ4 swapped AMC Rambler I went 80E as I didn't want the same problems.
I've attached my program file.
To data log, I'm using my laptop and the HP Tuners scanner program (MPVI2 pro) and there are no codes being thrown, but possibly when the truck was tuned DTCs were turned off or adjusted to not throw a code (airflow).
Here is the link to my HP Tuners post, but no one has replied there but me https://forum.hptuners.com/showthrea...ebuild-(Update)
I noticed the timing as well and figured this was either the cause or maybe even the effect of what is going on. The good news is I may have found the cause, air may have been bypassing the MAF!. The rubber coupler that attaches the (aftermarket) air intake tube to the throttle body completely fell apart; rubber doesn't last long here in the desert. The air intake manufacturer doesn't exist anymore so can't purchase a replacement and they used an odd sized tube so finding a coupler that will work is proving difficult. I've ordered another complete air intake, but it seems most of these are not in stock either. I have it band-aided together right now, but haven't been able to datalog yet, plus I want to make sure no air is bypassing the MAF and can't guarantee that with my band-aid; I may be able to grab another data log today though and see if there is any improvement or change.
About the TCC, looking at my program it should never be locked in 1st or 2nd and the slowest release is 25mph in "cruise". I think I may have some issues here besides the idle/timing. I was wondering if the "TCC Applied" shows commanded or actual? I'll log AFR and TCC slip "Angular frequency" and "Ratio" as Slip RPM is not an option. I can't remember if I have a bung to install my wideband in the truck, so AFR my be narrow band only.
Thanks for all the pointers!! I'll keep this updated as I get another log and new air intake.
I can't look at the log at the moment, but based off what has been said so far.
DBW or DBC?
What is the IAC position when hot in gear?
What's the STIT?
It's DBW, and with the engine warmed up, the throttle position is around 15%. I don't have STIT logged, is that Idle Adapt (STIT) [Mass Flow Rate], that's one I've never heard of. What does that log? Thanks!!!
OK, finally got delivery of the air intake kit last night and installed it this morning. I've got two logs, one on a cold start with a short trip and the other just a short trip. Neither are with the engine totally warmed up, ran out of time, but hopefully I can get a large log tomorrow with plenty of highway cruising. To be honest I'm not sure I see a change in the timing as it still looks a little weird to me, however the short trip I took I didn't have any idle hunting going on, but again, it was a short trip. I also logged TCC slip percent and RPM, and I'm guessing when RPM ~ matches engine RPM it's free and when TCC RPM is less than engine RPM it's locked up? Also, it looks like 210% is free and below 100% is locked. If so, to me it still looks like TCC is active in 1st and 2nd which it should not ever be, unless I'm missing something? Hope to post again tomorrow with a longer log. Thanks!
Got a few things done today, a long data log and also went to the transmission guy's shop as all my logs continue to show the converter being locked. He took it for a drive with me in the passenger seat and he's 100% convinced that I have an issue somewhere and he feels the converter is locking up when it shouldn't be, e.g. in 1st gear. Glad I'm not crazy I've posted the log anyway, but until I have known issues fixed, I feel it's kind of mute looking at it. Unfortunately, I'm leaving town for a little over a month in a few days so won't have him take the truck until I return. So, I'll update in the middle of Oct when I have news!!
Look at 3:45.. at that moment your Torque Converter Clutch is actually locked up.. The TCC SLIP RPM confirms it.. Prior to that point, though the log is showing that the TCC is applied "YES", the slip RPM is showing you that the converter is not actually locked up 100%. Try these settings. With these changes in apply speeds, it should never attempt to lock up the converter until you are in 4th gear, and then only when above the speeds in the table. Also, change your Min & Max TCC duty cycle tables so that you will feel an absolute apply when the TCC is commanded on-it should feel like a gear shift.. Then log again. With these settings it will be obvious to see when the TCC is applied as you will feel it, and it will show a drastic reduction on the TCC SLIP RPM reading. The RELEASE is simply a point in throttle pedal application-TPS at this percentage or greater, then the TCC is commanded OFF. If you are at 70% throttle its likely that you are wanting to pick up speed aggressively and do not want the converter locked up at that moment anyway. The only people that LOCK converters at 100% throttle are dyno-monkeys in an attempt to smoke your torque converter, or your transmission, or both. The only time you should be locking a t/c at full throttle is if you have a multi-clutch t/c designed to handle big horsepower, or torque, that is capable of being locked and holding the power.. A stock, or mild performance t/c with a single clutch is not going to last locking up at full throttle.
So I finally got back in town about a month ago and my tranny guy had the truck for close to three weeks; he did mention to be patient. Turns out I had a new but faulty pressure switch, and while idling the tranny would go from 1st to 2nd back to 1st over and over. Been driving it for over a week and no issues, the truck drives exactly like it did prior to the tranny failure. So I'm guessing I had two issues causing the problems I felt, the air intake tube and the pressure switch. Hope this helps someone. Thanks everyone for their help and input!!
08-31-2021, 06:25 PM
idle hunt after transmission rebuild 
I've posted the log anyway, but until I have known issues fixed, I feel it's kind of mute looking at it. Unfortunately, I'm leaving town for a little over a month in a few days so won't have him take the truck until I return. So, I'll update in the middle of Oct when I have news!!
