Are you referring to my 350 being worn out and it shouldn't act like this? That makes me feel a bit better. I do know when I set the timing advanced, it runs really great but, I was too lazy to go down the path of the pinging it caused so have kept it at 0... But it was fun, I don't remember paying attention to the 4th gear shifting situation as this was a couple of years ago.My old truck is just the opposite,just a little pressure on the go pedal makes the TCC unlock and just a little more pressure causes it to kickdown. I contribute that to a worn out 305 that never had any balls to begin with.
A member I helped with his yukon has a pretty newish motor and transmission with 4.10 gearing and I noticed the same lugging in overdrive as well tbh.... but it moved great when it came out... but I was passenger so obviously can't tell 100% but we discussed as he was trying....
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