P1870 and no lockup

[kwk174]

I have just installed a 3600 stall in my 4l60e. While driving i do not have any lockup until I clear the dtc's but when i look for any codes it only came up with a P1870 code once. I have a ecsb sierra with a 370, 4l60e with the vac-mod, 3600 hughes stall, heads, cam, and exhuast. My question is when i installed this stall do i need to go back in to retune for my transmission? Cause i have read of the issue with any detection of misfires the lockup will not engage. I have a 112 lsa on my cam so misfires are showing but it is a false reading. If anyone can help with this issue that would be great thanks.

[almarconi]

Yes, you will need to make changes to the programming for the torque
converter. There is a spreadsheet you can use from Bluecat that will calculate
the values for TCC apply and release, WOT values and part throttle just to name a few. Depending on what's been done to your trans you can also remove some or all of the torque management. The P1870 code is for a
slipping component. This may be due to a worn component in your valve body,
I believe transgo and/or sonnax sells a fix for this. Has the transmission recently been rebuilt?

[kwk174]

yes it was rebuilt 1 year ago with the vac-mod in place. Anyone know of a link for the spreadsheet?

[almarconi]

Its on the main page,the post is by bluecat

[jimmyblue]

TCC min duty should be bumped up for starters, and all
desired shift times zeroed. This will make the trans quit
learning how little line it can get away with, and being
wrong.

Little converters need more line pressure at cruise. Look
to your Trans General Pressure for TCC-locked line adder.