4l60e 3rd gear issues need help
 

im having issue with my 4l60e it shifts fine 1st and 2nd and the when it shifts into 3rd,it just revs like in neutral but goes into gear at wot.
Is it the clutches or what could it be

Search for "3rd gear slips" in the Automatic Transmission section - current over 230 threads. Here is one:

https://ls1tech.com/forums/automatic...-no-3-4-a.html

Yes, nearly always the 3-4 clutch has failed and the trans needs a rebuild. If you have it rebuild locally, I highly recommend having a 4l65E rebuild kit used as it has a better 7 friction 3-4 clutch. Might cost an extra $15 and will fit any '96 or later 4l60E. A Sonnax boost valve (#4l60e-lb1) is also a great addition that will firm up shifts a bit and extend the life of clutches.