e38, t42 and 4wd lo

[yevgenievich]

I have e38/t42 swap in a 4x4 configuration. 2008 gm calibration is used from a 4x4 truck with a manual transfer case. But there is a segment swap for 4l80e. When scanning it picks up and shows when 4lo is engaged, but shifting and driving becomes lagged. It will eventually shift around 3k rpm, but driving as if riding brakes the hole time ( A lot of throttle input just to move). Is there a way to access tables that ecu/tcm uses when in 4lo? Or is it a sign that segment swap did not work correctly?

Was wondering if need to hunt down manual t case with 4l60 calibration and start with that instead of a 6 speed starting point.

This is in a 97 burb running 8.0l BBC and 4l80e

97_burb_08e38_t42.hpt

[STAGEUP]

Sounds like your 4l80 is stuck in limp mode. (stuck in 2nd gear). Verify that you have 12V going to the trans harness

[yevgenievich]

It shifts correctly and as commanded when not in 4lo, but becomes erratic with essentially large power loss when in 4lo

[castorjames]

It shifts correctly and as commanded when not in 4lo, but becomes erratic with essentially large power loss when in 4lo

hello, did you wire?:

PIN: 3-----TN/WH-----Axle Switch Signal

[yevgenievich]

signal is wired to ecu. When scanning, it shows correctly when 4lo is engaged.

[yevgenievich]

Attaching a scan and also channel config. 4lo shows as yes, but 4lo axle actually shows no. I found the throttle map that is used in a change and modified it, but shifts basically happen at 3k rpm