Stock transmission too firm 1-2
Guys I had a post in the engine section by mistake, seems this is the more appropriate area.
I did this swap years ago and only recently swapped back to an automatic. Was a T56. Tune was hacked up by wait4me before I learned better..
The trans I put in is COMPLETELY stock.. No stall, no kit (to my knowledge), Nothing but fresh fluid and a good cleaning. Pulled from an 09 3500 ATT van so I assume he didn't have an HD2 kit in it.
WOT performance is on point.. it shifts firmly and runs great..
HOWEVER, driving around town the 1-2 and 2-3 are very firm.
The ECM and tunes in the ECM are from an 06 truck. Both GMC.. I initially posted my tune and log in the other section and a person noted that my trans temp was stuck at -28F so I found a bent pin and have since fixed that.. Shifting hasn't gotten any better.
Shift timing points can be tripled and it doesn't seem to make any difference.. I don't fully understand how to make line pressure tweaks to make it shift softer and I also don't fully understand how to log trans pressure.. I don't think I have it in my log file and can't seem to find anything thats name makes sense to me.
EDIT: Found the issue to be one pin out of place in my harness that controlled the trans pressure solenoid. All is well - trans shifts like butter at light throttle now but is still firm enough on the high end.
