4l60 help! Need advice

[Twodrhoe]

I have a 1996 two door 4x4 auto trans (4l60) when I got the truck it had a slight slip/flare going into 3rd. Recently did a induction service and took her out and ran it wide open. Now it dosent want to go into 2nd. I have to wrap it up in 1st let off then it will shift into 2nd and its all good? Anyone ever had or seen this issue? Is it time to think about rebuild? Not really wanting to go that route at this time but if its that time, guess I dont have a choice. Thanks!

 

[Freedom Motorsports]

Sounds like you need new solenoids in the tranny. I would check the 1-2 and 2-3 solenoids before something really tears up. They aren't that hard to change, just taking the pan off and removing them, they are at the front and back of the valve body.

 

[SunlitComet]

1-2 shift does not happen at WOT until you let off the gas Middle case leak in the 2nd gear apply circuit (servo assembly or 1-2 accumulator). Doublecheck by using the pressure gauge and watch for a big drop when the PCM commands 2nd gear. Worst case poor line pressure rise (see below). Try replacing the ThrottlePosition Sensor ThrottlePosition Sensor (TPS).