Transmission not shifting properly

I have a 1993 Chevy Pick up, 4x4, i had the transmission rebuilt, the ignition module has been changed, and the computer, and the truck still only has 1st and 3rd gear. The mechanic put a “shift box” on it and the transmission works fine with that on it. The mechanic said he switched out the chip from my computer to the replacement, and made no difference. Could the chip se be the problem? I had a new case connector for the truck that the shop put in, but because the color pattern was not the same, he thinks that may be the problem. Help?

Was the same problem there before the rebuild and the ignition module replacement?? What do you mean that you only have 1st and 3rd gear?? What does the transmission do when you put the gear selector in “R”??, D4, D, L1, L2??? Can you be a little more specific in what the transmission is doing??


it has Reverse, 1st gear and 3rd gear in the drive gear ranges, has 1st gear in L1, and 1st and 3rd in D and overdrive. This is the same issue I was having both before and after the rebuild and such.