IV Gen Transmission Tuning tips

[madden]

I've tuned quite a few third gen 4L60-65 trannys with great success but had less luck with the fourth gen trannys in 1/2 ton gm trucks. I've attached a file of an 08 5.3 chevy 1500. We have already installed a corvette servo. On this particular tune I ended up leaving the shift pressures stock and just removing torque management. The truck shifts nice but has some inconsistent WOT 1-2 shifts. Sometimes it is almost too hard and other times it acts as if the truck is cutting fuel or timing during the shift. I've noticed that the desired shift time setting is not present in the gen IV computer (or I don't know where to look). In any case, I think this thread could be useful if a few experts or other folks who have had good luck with the gen IVs could chime in.


On another note, I will also say that I tuned a different 08 truck and we didn't install a servo in it.................... it really shifts great at WOT.... go figure.

One other question...... Does the TCM in the 4th gens "learn" and adapt shifts?

Thanks for any replies.

[madden]

Here's the stock file, I forgot to attach it before.

Oh, and I just found out that the other truck that I mentioned (with the stock servo) has now developed this same inconsistent 1-2 shift. ??

I'm wondering if it may have something to do with engine or transmission temperature.

Anyway, I'd really appreciate some help.

Thanks,

J


Well I tried to attach the stock file. Something's wrong with the site right now.

[flea]

Check to see if the truck is using the most up to date GM OS calibration. GM periodically updates OS's for any number of reasons and I believe (if memory serves) the problem you are experiencing might be linked to this.

You can compare the current OS (under calibration details) to the most recent from GM. If they are different you have an out dated OS. I can't find the link to the GM website right now however I know it's been posted on the forum.

[madden]

Thank you for your response

I'll look into this.

Anyone else who has experienced this, please chime in.

[madden]

Check to see if the truck is using the most up to date GM OS calibration. GM periodically updates OS's for any number of reasons and I believe (if memory serves) the problem you are experiencing might be linked to this.

You can compare the current OS (under calibration details) to the most recent from GM. If they are different you have an out dated OS. I can't find the link to the GM website right now however I know it's been posted on the forum.

Will we have to take the truck to gm in oder to have the os updated or are there alternatives?

[mattgallan]

Subscribing.

[bodycreationinc]

Subscribing.

i have a 2002 avalanche and i converted my s/c truck with a 4l80e 4x4 it had a 4l60e but am looking for a file/tune so i can download into my ecm so the trans can work need help please

[josediaz]

sorry mate no idea on this issue

[TexasGMC08]

Ive tried the tune that was received from PACT for a 4L60 and Its not working out to well will my truck. Can someone take a look and guide me on things that need changed???

TexasGMC_LS1_Tune_misfireCounts.hpt