Fixing Lazy 1-2 shift in 4L60e

[lesmyer]

A new tuner here. Stock 2004 Avalanche 5.3 with 4L60e. Got rid of my P0327 and P0332 SES light without disabling KR. Now I'm interested in firming up my 1-2 shift at light-moderate throttle. Right now it seems to spend way too long during the shift - almost like it has two steps to it. If I put it in tow mode. the 1-2 shift feels fine to me. It has been that way for 5 years so I don't believe the trans is having issues.

Can I replicate the feel of the tow mode 1-2 shift by entering the shift time of the 1-2 tow mode shifts into the normal table? Is there anything else I should be changing, other than the entire row of 1-2 shift times to 0.300, or is that all I need. I am assuming that the PCM will adjust everything to target the new shift times.

My tune and a generic log are attached because it seems I am supposed to. Also the transmission shift time tables for normal vs performance mode.

2004 Avalanche Z71 5.3 PO327 PO332 turned off.hpt edwardsburg.hpl NormalTable.png TowMode.png

[edcmat-l1]

Upshift pressure modifier tables. You need to log delivered torque. I think it's delivered engine torque to be specific. Need to know where you are in the table. I'd start by making all the negative numbers zero. Most tables will have negative numbers down in the lower torque areas of the table and that's where you want to make your improvement.

[lesmyer]

That's making sense to me.

I'll log delivered torque for some different 1-2 shifts this weekend and post. Please come back then and advise. I do have an out of town trip next Monday. Thanks much in advance!!

[Alvin]

A new tuner here. Stock 2004 Avalanche 5.3 with 4L60e. Got rid of my P0327 and P0332 SES light without disabling KR. Now I'm interested in firming up my 1-2 shift at light-moderate throttle. Right now it seems to spend way too long during the shift - almost like it has two steps to it. If I put it in tow mode. the 1-2 shift feels fine to me. It has been that way for 5 years so I don't believe the trans is having issues.

Can I replicate the feel of the tow mode 1-2 shift by entering the shift time of the 1-2 tow mode shifts into the normal table? Is there anything else I should be changing, other than the entire row of 1-2 shift times to 0.300, or is that all I need. I am assuming that the PCM will adjust everything to target the new shift times.

My tune and a generic log are attached because it seems I am supposed to. Also the transmission shift time tables for normal vs performance mode.

2004 Avalanche Z71 5.3 PO327 PO332 turned off.hpt edwardsburg.hpl NormalTable.png TowMode.png

0.3 is still a pretty long shift time. 0.2 and even 0 for 4l60's is fine. After that upping pressure would be the way to go.

[edcmat-l1]

0.3 is still a pretty long shift time. 0.2 and even 0 for 4l60's is fine. After that upping pressure would be the way to go.

I agree. 0.0 or 0.1 is what it should be set at. My opinion though the pressure offset tables give you more of that umph! than zeroing the shift times.

[blindsquirrel]

trans.1-2.before.png trans.1-2.after.png

I zeroed mine out to fix that same ~1sec 1-2 and double bump, and after a few months the adaptives slowly dragged it back out to where it was before. I set it to .250 across the board (shift actually takes right at .300s on this one) and it never happened again.

The double bump is because the spark timing is only pulled for a fixed amount of time, if the shift takes too long it gets added back in before the shift is complete.

[lesmyer]

I worked tonight on configuring VCM scanner to monitor quite a bit of transmission stuff and prepared a graph of Delivered Transmission Torque (average) at MPH vs MAP. I'll get a log of the stock trans tune posted tomorrow.

I'll try to get additional logs after changing both 1-2 shift time and 2-3 shift time in the tune to 0.2 sec and then to 0.1 sec and then to 0.0 sec? Does that seem like a good compromise to everybody's advice for now?

How can I keep the adaptives from moving things around? I would have though the adaptives would target the desired shift times instead of drag them away from the setting. Something I'm not understanding here.

Thanks to all!

[blindsquirrel]

Something I'm not understanding here.

Good, then you read my post correctly - I don't understand it either. But as long as the commanded shift time isn't significantly shorter than what the trans is actually able to do, the adaptives don't step in and make it go back to ~1sec shift times. So don't zero it out and that won't happen.

[lesmyer]

Changed shift times to all zero and logged transmission parameters including delivered torque, map sensor, vehicle speed and others during various shifting conditions. Delivered Torque seems to be a minimum of about 80 ft lb at lightest throttle, about 120-140 at moderate throttle, and 260 max at heaviest throttle shift points.

I'm really not seeing much (if any) difference from changing the shift times to zero. 1-2 and 2-3 shift times always seems to be reported extra long and light throttle 1-2 shifts are 2-step feel and quite long for whatever reason..

I didn't see any point to changing the shift times to 0.1, 0.2, and 0.3 since changing to 0.0 did not seem to affect it.

edcmat-l1, can you spot anything in the log? Anyone else?

Thanks in advance
Les

23-10-21 13-50-52.hpl
2004 Avalanche Z71 5.3 P0327 P0332 turned off - Shift 0.0.hpt

[lesmyer]

Changed shift times to all zero and logged transmission parameters including delivered torque, map sensor, vehicle speed and others during various shifting conditions. Delivered Torque seems to be a minimum of about 80 ft lb at lightest throttle, about 120-140 at moderate throttle, and 260 max at heaviest throttle shift points.

I'm really not seeing much (if any) difference from changing the shift times to zero. 1-2 and 2-3 shift times always seems to be reported extra long and light throttle 1-2 shifts are 2-step feel and quite long for whatever reason..

I didn't see any point to changing the shift times to 0.1, 0.2, and 0.3 since changing to 0.0 did not seem to affect it.

edcmat-l1, can you spot anything in the log? Anyone else?

Thanks in advance
Les

23-10-21 13-50-52.hpl
2004 Avalanche Z71 5.3 P0327 P0332 turned off - Shift 0.0.hpt

Changed back to original tune for transmission - had to tow 400 miles Monday. Anyone have any advice for me based on my last posted log. If not I think I will try copying the pressure table for the performance/towing into the normal table and hope that the shift points are not raised - just firmer shifts. What do you think?

[edcmat-l1]

If you look at your pressure modifier tables, they all go negative at the lower torque columns. You either zero those cells or apply positive numbers. This file attached may be too aggressive but it's this table that needs to be modified.

[lesmyer]

If you look at your pressure modifier tables, they all go negative at the lower torque columns. You either zero those cells or apply positive numbers. This file attached may be too aggressive but it's this table that needs to be modified.

Thanks much for responding! So plan is to alter pressure modifier tables and leave the rest of the trans tune stock? At least initially?

Or did you make the attached file for me to actually try?

[edcmat-l1]

Try it out. All I changed was one table, the 1-2 pressure modifier. Use your compare feature and you'll see. If it's too aggressive back it down some. Only thing it should change is the 1-2 shift feeling.

[lesmyer]

Try it out. All I changed was one table, the 1-2 pressure modifier. Use your compare feature and you'll see. If it's too aggressive back it down some. Only thing it should change is the 1-2 shift feeling.

Thanks much. I will and then report back later this weekend.

[edcmat-l1]

Glad you found something you think you're happy with. I've tuned hundreds of these and if that single setting I gave you didn't do any better than that your trans is probably just worn out.

[lesmyer]

Glad you found something you think you're happy with. I've tuned hundreds of these and if that single setting I gave you didn't do any better than that your trans is probably just worn out.

agree - might be original 180k trans. It's days may be numbered! Thanks again!
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