well coming home from carshow today trans started slipping in overdrive,just going in and out. anyone had this issue? its a 98 4l60 out of camaro. but its in 69 camaro now. trans fluid still looked good,and shifts fine 1st 2nd 3rd. someone told me there is a speed sensor on trans didnt know if that might be issue. any help is appreciated

 

If you have a trans temp gauge, how hot did the transmission get? Heat is killer to a 4L60E, I just had this happen in my 96 WS6 and would like to know too.

 

Check for codes first. Are you sure it,s 4th and not lock up?

 

Factory converter?

 

No mine is a 3200 lock up style and it isn't lock up for sure. My issue feels like the car goes in to neutral when it shifts into 4th. I'm thinking its the 2-4 band but I'm not positive.
Can I bring it to a parts store and have them pull codes? I do not have a CEL on at this time.

 

I just read OP's question again and yes it could be lock up in his case. These transmissions, 95+, use a PWM (Pulse Width Modulated) converter lock up, which can cause locking and unlocking depending on the driving conditions. Sorry wnarunm I didn't read your post close enough.

 

Still, you should check for codes first. Some codes that affect converter lockup (like misfire or slippage) don't immediately turn on the MIL light.