I have a 91 Suburban 2500 that came with a 4L80E. I just finished up the 5.3 swap. The 5.3 had a 4L60E attached so I had to repin the harness and segment swap (from another 04 with a 6.0). Truck runs great but shifts like crap. I did the Bluecat tune and it helped with the shift point but not the neck breaking 2nd gear shift or the ridiculous downshifts when you roll on the throttle a little to aggressive. I've been reading the Force motor is different in these older trans? I have no Idea what that means or how to fix it. Do I need to change internals to bring the transmission up to par with my PCM or can I fixit in software?
More info I found on the interwebs. Hope this isn't true.
"#6 ? Nov 8, 2017
94 and up trannys were built with this new force motor,new spacer plate, and the elimination of the torque signal compensator valve inthe accumulator housing. These parts are not backwards compatible with the 91 ?93 trannys. You can?t reprogram the TCM to accommodate the 614 Hz force motor. Youneed to install the correct force motor for your tranny. DO NOT drive until done. 91 ? 93 trannys forcemotor OEM part number is 8677314"
Reply With Quote