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I've been experiencing for awhile a harder and sharper shift than normal when the trans goes from 2-3. It seems to shift harder before the trans temp has warmed all the way, and it used to be buttery once the whole truck warmed up, but now it feels sharp at all temperatures, just more pronounced when cold and during medium to hard acceleration. Mild to slow accel is still a smooth shift.
Any of you have any ideas on why this might be happening? Could I have a solenoid on the fritz?
You might have a solenoid going. You might have a much simpler problem. The first thing to try is to disconnect both negative battery cables, or alternatively, unplug the PCM. This clears the shift adaptive software. Sometimes that software can learn itself into a hole that it can't climb out of.
Fluid is Mercon, made sure to get the right stuff! Did the fluid and filters earlier this year, no more than 5000 miles since then. No codes but only have SGII to look for those. Might need to search for hidden codes?
If it is in fact a learning issue I suppose I ought to try it in tow-haul and see if the shift is similar. If it's smooth in tow-haul but hard in normal that would signal a brain issue, no?
I'll unplug tonight after work and re-connect batteries before I leave for work in the morning. Thanks Mark!
Fluid is Mercon, made sure to get the right stuff!
If you really used MERCON we've found your problem. MERCON will KILL the solenoids in your transmission. It will cause harsh shifts, and it will eventually cause your transmission to fail. It is the wrong fluid for this transmission.
You can only use MERCON SP or MERCON LV. Anything else is death to the transmission.
You might still be able to save this one. If you can find a place that has a hot flush machine (they are very rare) a hot flush with MERCON SP or MERCON LV will do. If not, drain the pan, refill, drive 10 miles, and do it again. Then once again.
Mercon LV is what I used, sorry I was not fully clear earlier.
The relearn has smoothed 2-3 out quite a bit after a few days of driving. I have a habit of lifting a little off the accelerator trying to encourage a shift, would this hurt the learning process?
Fluid is Mercon, made sure to get the right stuff! Did the fluid and filters earlier this year, no more than 5000 miles since then. No codes but only have SGII to look for those. Might need to search for hidden codes?
SGII only sees the major fault codes that will trip your SES light.. it wont see the more minor ones that can help with diagnosis..
Originally Posted by Mark Kovalsky
You can only use MERCON SP or MERCON LV. Anything else is death to the transmission.
even all the aftermarket companies recommend AGAINST using anything other than motorcrafts SP/LV fluid.. to me thats always put a little fear in me to try swapping out fluids when even they are saying not to swap off..