I just put my new motor in, with same old transmission. The trans was 100% fine when tooming out to do the build. After I got done with my motor I then put everything back in. well I get a base tune done and he changed my shift points. Well I took it down the street but didnt get on it because I was running open headers. So I didnt check to see if my trans was fine. I have topped my trans fluid off so I thats fine. well I take it out and get on it alittle and it shift ok. Not great so I was thinking it was my tune making shift like that in 3rd gear but I stop at a friends house showed him my car. As I was leaving I once again got on it and 1st 2st shift fine but going into 3rd it rev really high and tops, not bad jus where I could hear it. So I sow down. Get to the coming up light and start to take off. Once again 1,2 fine.. This time it dont even go in to 3rd at all. I have not drove my car over 100 miles, I have transmission fluid in it. my transmission set for like 6 months, but was coverd so nothing could get in it. So..... What my question is what could of happend to my trans could I of blow something off, broke something. Or could something little be off. What would make this happen, and what are somethings I could check to see if something off or my transmission going out. Thanks for the views. Hope someone can help.

 

Sounds like 3-4 clutch pack is toast. There is a slim chance you may have a bad shift solenoid.

 

Did you put the transmission tables back to stock and try it that way?

 

3-4 clutches are gone. Can't be a solenoid. Both solenoids "Off" is 3rd gear. 3-4 failure is a commom problem in 4L60E's. Most likely just a coincidence.

Frank