I have a B&M megashifter in a 1984 camaro z28 with a small block 350 and 700r4 tranny, from park to reverse, nuetral, and drive, the shifter is fully functional, after that, when trying to rachet down to 3,2, and 1, the shifter makes the rachet motion but does not grab the gear to put it down unless i pull on one of the plates withing the shifting mechanism, nobody can figure this out, could someone help???

Did you install it as per the instructions.It sounds like the cable is not adjusted right.Also the shift cable needs to be looped correctly over the top of the tranny,due to it's length.
I hope this helps.

I'm with alicat on this one. I had a tricky time with my megashifter, but nothing that couldn't be solved with a bit of tweaking. You should be able to download the installation instructions from them, I had to when I swapped from the 700r4 to the th350.

If I remember correctly, you're supposed to adjust the cable with the shift in neutral (but make sure to have the car secure enough to not roll you over). I had a shop swear up and down they didnt touch my cable when they did some work on my transmission (gotta love when they lie straight to your face) and I almost crashed since I could not get the trans into gear from reverse.