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Have the plate, got new balls as well, forgot to order the separate accumulator gasket so waiting for that to show up. Have a road trip coming up, and decided I'm not going to risk causing other...

Got a plate and gaskets on the way, we'll see where that gets me.

New valve body, solenoids, and accumulator are already in the trans, but the separator plate is an interesting thought. There was what my inexperienced eye thought was a small amount of wear, but...

Still haven't resolved this issue. Put plenty of miles on the truck towing my toy hauler, no issues aside from having to pedal it after a 3-4 shift to get the converter to lock again. The shift time...

I'll post it in a bit, on vacation with no computer.

I do have the latest softwares installed for both V7 and V8, and updated the flashscan while I was troubleshooting so all set there.

TFT...

@joecar thanks for the tip, I did switch to using TIS which shows that TIS and output speed seem to be what the gear ratio parameter is calculated off of, and TIS shows the engine speed instability...

Here's the log that goes with it. Several shifts through the gears, generally 3-4 is at low load. Shift times are occasionally acceptable if I happen to be rolling off the throttle during the shift,...

Needed to get some more logs and finally got that done. VSS is correct, all the other sensors are working properly in the trans (turbine speed, output speed, temperature). PCM is the original for...

Did some more logging. The gear ratio PID shows ratio falling from 1:1 (3rd) to 8.75ish:1 before eventually falling to the correct 0.75:1. This happens even if I disable lockup in 3rd gear. The 3-4...

2004 Suburban 2500 with the 8.1 and the 4L85E. Fundamentally the same as the 4L80E.

Ever since I got it, every time the transmission shifts from 3rd to 4th and the converter was either previously...

Yeah, speedo a few percent high vs. VSS is how they have always been set up on the few GM vehicles I've played with. I think as long as the speedometer/odometer/cruise/instant economy work properly...

the minimum TPS thing definitely is definitely true here too, even with those TCC tables. I'm not sure the .CAX that Lextech was using would work or not, and even if it did he doesn't seem to be too...

I think you'd get a giggle out of my current tune - I ended up at very similar changes to the shift patterns that you have. 3-4 upshift in particular, the lines are almost on top of each other. I...

Strange. Okay, I'll deal with it then.

@joecar - no worries, I'll just be brief in my messages or multi post longer stuff. Now that I know it will let me do short posts at least I can work around it now.

@joecar - no worries, I'll just be brief in my messages or multi post longer stuff. Now that I know it will let me do short posts at least I can work around it now.

@nonnieselman - I think you'd...

Yep, 3.73 gears and stock size tires on stock rims - I believe 245/75r16.

I haven't touched the speedo or VSS parameters. I have not checked them against each other, but I think the speedo was 2-3...

Let's see if I can do a short post: stock cal shifts locks in second at WOT, shifts 2-3 in lockup, and shifts 3-4 in lockup when you lift. 3-4 WOT doesn't matter to me, it is a suburban. Stock cal...

Well that worked. Odd. I'll try this again:

I would have agreed with your comments if the factory tune didn't do exactly what you're saying shouldn't be done. I've not seen any other GM vehicles...

I've tried to reply and it says the post has to be approved by a moderator. Is it just going into some black hole in the internet?

EDIT: any time I write more than a sentence, I get the moderator...

So all of your points are what prompted me to post here in the first place.
a. I would tell me I am crazy too, if I didn't see it for myself. With the stock, untouched tune straight from GM, a WOT...

2004 Suburban 8.1 with the 4L85E transmission. Trying to improve efficiency and responsiveness a bit as the stock transmission calibration does not at all make use of the torque the 8.1 has to offer....