Hey guys, I put a rebuilt 700r4 into my 86 trans am 305 tpi. After the install my speedo stopped working and it set code 24 for vehicle speed sensor. I'm wondering if the new transmission requires a different gear on the speed sensor or something. I still have the stock 273 rear in the car. Sorry if this is noobish, I've neglected this issue for a while now, I've been ordering a bunch of parts for the car and want to get this resolved when I put in a new torque arm mount and trans mount. thanks

Put the VSS from the old transmission in.
You probably have a different VSS than what's correct for '86, or a bad one. Wrong tooth count gears / wrong ratio wouldn't set a 24 if the VSS is working / correct.

Or did you forget to put the plug back on the transmission?

I looked over the transmissions warranty and receipts and it says, "speedo gear: none/ use gear from old transmission." I did this trans swap probably over a year ago and forgot to look in the tail shaft. I bought a rebuilt trans from an online trans builder after putting in two consecutive bad used transmissions, I was in such a rush to finally get the car driving again for school and work that I didn't bother to even check. My stupid mistake. I knew I had the code for the vss since day one but figured maybe it was the wrong gear. The good news is that the transmission has worked and shifted perfectly for over a year now. Thank you

Nope plug was in, I just figured it out though. Turns out the rebuilt trans never came with the speedo drive gear. After putting in two consecutive bad used transmissions I was in such a rush to get the car running that I overlooked that. The cars been shifting perfectly for over a year now, just figured that I should finally look into the vss code I've been having. Thanks