2000 blazer was having transfer case problems in process it also started having shift problems. Replaced transfer encoder motor and control module. Transfer case functions is working perfectly now but transmission is not shifting right.

Borrowed a Snap On Modis diagnostic computer. No trouble codes for the transmission (does have a mass air flow sensor error on engine codes). However, when the MODIS is hooked up the transmission shifts without flaw. Once unhooked it is ok but the longer you drive (mile or so) it deteriorates back to not shifting.

Without MODIS hooked up it shudders jerks and won't shift up or down willingly.