Diablosport Forums

Hey guys. I'll try to keep backstory to a minimum, but I suspect the details are probably relevant.
00 5.3/4l60e in my runner. I've done a ton of 5.3/6.0L swaps, never run into this before.

Original trans was on it's way out and I wanted to grab a 65e anyway. Found a local rebuilder who said he had one and would rebuild it for me (standard rebuild with HE clutch/band/etc), and I had him throw in a Sonnax reaction shell, vette servo, and transgo HD2 kit. Told him to build it conservative as this is my daily driver and rock crawler.
Got it back. It's not a 65. At least it's RPO code M30 which is a 4l60e case. Builder swears up and down it's all 65e parts internally, but he also gave me a new 4l60e TC to go with it, which as far as I know, does not fit the 65e input shaft. Either way, shifted like shit. 1-2 is crazy harsh. It'll break my DS if I'm not careful. Chirps 40x15" tires at part throttle. Told him about this and he said it'd be a combination of the .500 boost with the vette servo, and that he'd fix it. Before I brought it back to him, I wanted to test everything in low range as well. 1-2 harsh, 2-3 doesn't happen. Just shifts directly from 2nd to 4th almost every time (only in low range, but it does occasionally do it in high as well. just very rare). Once in 4th, with part throttle under a little load (ie: climbing), truck starts bucking like it's trying to shift down to 3rd and then giving up and going back to 4th, or like something is slipping. Manually shifting into 3rd works, but it also bucks under low at low throttle. I can't see a gear command change on the InTune logs, but i'm not even sure if it includes them. OBD adapter to the tablet also doesn't show a command, but it only updates once a second and according to the logs, the bucking happens every 0.5s. Trans also stalls out the truck when shifting from 1st to reverse in 4lo with any momentum at all. Again, I've never seen this happen with any of my swaps, nor even any stock vehicles.

Took it back to trans builder. He had it all day and said it was all fixed. I grabbed it. 1-2 no change at all. I chirped at 10% throttle before I even got out of his shop, but he'd already gone home for the day. Tested the 3-4 in low and same deal. No difference at all.

Builder says the 1-2 is still the .500 boost plus vette servo. That's what he said before I brought it to him, so I'm not sure what he changed. I suspect he didn't do anything as he told me he hooked it up to his scanner to look for the low range issue, but my OBD adapter was not touched and the tablet never lost connection to the ECM. Plus, he says he's sure the 3-4 low issue is ECM/command related, but didn't mention that he'd proven it with his scanner... This is why I haven't paid anyone to do work for me in nearly 20 years.... Every goddamn time man...

Anyhow, builder also says the low range issue is a tuning problem. I argue that the issue didn't exist before installing the new trans, but he doesn't care. Says he's 100% sure it's not a transmission issue, so I need to be able to at least show that the bucking isn't the ECM commanding a gear change.

Is there anywhere in the logs that'll actually tell me what gear has been commanded? I can't find it. I've can't find an option to adjust low range shift points... I'm told now by support that this option doesn't exist for my 00 ECM (though before I bought the tuner, I was told it did). I also tried setting the 3-4 pressure firmer and 1-2 softer (as far as it'd go negative) and didn't feel any change at all. Any chance someone could take a look at my logs and my current tune, and tell me what they think is going on?

P.S. I've called several other transmission shops, but most of them insisted that you can't get into 3rd or 4th gear in low range.... *sigh*. They even argued about it. I've driven 4x4's since I was still shitting myself and never found a truck that won't do 3 or 4 in low, so I'm sorta out of options for advice locally. At this point I'm positive the trans isn't right, but I don't know if both issues are trans, or if the low range issue might be tune related. When I first got the trans installed and noticed the harsh 1-2, I did try dropping the 1-2 shift pressure, so i figure there's a remote possiblity that the InTune messed with my low range tables somehow?

Thanks for any help guys. I already had to cancel my camping trip with my daughter this year because of this transmission. I've got another trip I've been planning for a year, that I'm supposed to leave on Saturday, but at this point I've got people driving 20 hours to get here, and I've got no working truck.

I gotta be honest, thats a lot to take in, cliff notes would be great

If you think its a tune issue, put the stock tune back in, and see if it still behaves that way?

Well, long short, swapped transmissions. Rebuilt 4l60e with apparently 65e hard parts, sonnax reaction shell, vette servo, transgo hd2 kit.
1-2 harsh. Everything else mostly normal in high range.
In low, 3 and 4 shift wonky, but I actually figured out what's going on and i'm wondering if anyone can tell me if there is any possibility that this may be related to the InTune.

Grabbed my buddies scanner and discovered that the TCC brake apply circuit is always closed. Hit the brake, ECM still thinks the circuit is closed. It's definitely not closed. Reads 12v by default, and 0 when brake is applied. I even pulled the relay that feeds pin33 on C1 to verify. NO matter what, since installing the new trans and at the same time flashing back my stock tune, the ECM is always reading the brake switch closed. This explains the 3-4 jumping around in 4L. I'm riding the brake so the TCC shouldn't be able to engage, but the ECM thinks the brake is NOT applied.

But, the TCC shouldn't apply at such low speeds anyway so there's something really wonky going on with my ECU since flashing back the old tune. It shifts 1-2 normally (though very harsh) in low range, but then usually skips 3rd entirely and goes straight to 4th and immediately applies the TCC.
I've checked the entire harness for shorts and can't find anything. Transmission seems like its' all good at this point, but for some reason, the ECU just isn't reading that brake switch anymore, as well as commanding VERY early shifts plus tcc lockup.

well, the stock tune is unaltered, so its the same as it was prior to using the tuner, so it sounds like a possible electrical issue in the vehicle or trans.

mikel wrote:well, the stock tune is unaltered, so its the same as it was prior to using the tuner, so it sounds like a possible electrical issue in the vehicle or trans.

This is where it gets weird.

I have two issues, and both should mean that my TCC NEVER locks up, which is why i'm so confused.

The relay is wired correctly. The brake switch is normally open, and provides 12v to the tcc brake switch relay pin 86 when pressed. Relay pin 30 has Batt+ constant. Relay pin 85 is ground, and 87a goes to ECU C1 Pin33. This circuit is supposed to be normally closed, providing 12v to the pin unless the brake is pressed. When brake is pressed, the ECU CAN'T command a TCC lockup.
But, I checked the relay, and it's not even closing. It's always open on pin 87a. This means ECU pin 33 never receives voltage, so the ECU should never command TCC lockup, as it thinks i've pressed the brake. I've confirmed this with a snap-on scanner, multimeter, and about 10 electrical engineers from work. We are all absolutely positive that, at least when I'm not driving, there is NEVER any voltage applied to pin 33. TCC should never be commanded to lockup for any reason afaik right?

But, according to the snap-on scanner, when I reproduce the problem where the TCC locks and unlocks in 3rd and 4th at low rpm and low throttle with light load, in 4 low range, the ECM reports that the TCC brake switch does not have 12v, so the TCC should not be commanded to lock up, but it also shows me that the ECU IS commanding TCC lockup, and lockup is verified by doing the math to figure out transmission to final drive ratio.

At this point I am absolutely certain the ECU is commanding TCC lockup, in the absence of a 12V signal on pin 33. This should not be possible as far as I'm aware, and everyone I've asked about it (multiple red seal mechanics) say i'm not crazy. Something super fucky is going on inside the ECU.
Everyone who's looked at it says it's either the ECU has a physical failure that does not show up on any scanner, or the tune is telling it to command TCC lockup way too early, and without the 12v signal on pin 33. I know this is POSSIBLE to program, but I understand that the InTune should not have modified anything, given I flashed the stock tune. But what else could possibly account for this behavior? It started immediately after I flashed the first tune to this ECU, from my InTune.