94 chevy 2wd 1/2 ton pu 350 auto
shifts into first and second fine but that is all wont go into third or od

 

is your tranny a 4l60e?

 

im told it it but im not sure how can i tell

 

the letters 4L60E are cast into the side of the main case.....they might be there not super sure

 

only numbers on case are a big 20 on each side and 8680514 is on the drivers side of case, lets assume it is

 

when the truck shifts from 1st to 2nd what mph is the truck @

can you shift threw the gears on the coulumn when driving?

iv'e had a similar issue with one and could get it to hit 3rd when really on it,and it would shift hard...i hope your not in the same boat

 

have tried to shift manually still won't shift

 

An easy way to tell is the 4L60E has a drain plug built into the pan, stock, the 4L80E does not.

And what's the mileage of this particular truck? And the last time the transmission filter was changed?

 

well you cant always say if it has a drain plug or not. stock mine does not have one on my trans pan. and it sounds like clutches and planetarys dont feel like engaging. according to our recent talk in trans class last friday, check for codes. because the light aint on doesnt mean there arent codes. check the condition of fluids. if its burnt, possible internal issue. check all codes though first. it could also be a failing 3-2 solenoid.

 

You might have a bad third gear synchronizer. The transmission needs to be overhauled if that is the case. Have you checked to see if your transmission mounts are loose. Then again you may have a bad gear linkage binding.