Namu

So I've got this 1993 K3500 that was originally a 6.2 automatic 2wd but was converted to a 5.7 with a 5 speed 4wd and this was obviously a home job because there's a lot wrong with it. I've gotten a lot of it done myself but I'm somewhat stumped on what the issue is with the speedometer. The speed sensor wire was disconnected from the speed sensor but it was plugged into the transfer case so there's that at least. The connector and sensor were caked with mud so I bought new ones and that did not fix my problem. I also replaced my dash cluster because they had gotten into that for some reason and ripped the paper circuit board on the back so all the lights on the right didn't work. I've run through where the wires go and they seem to be fine. This might be a problem with my VSSB, since I don't know if they swapped it with the drivetrain swap, and I do not know what code I need for a 5.7 with a 5 speed. Also, does anyone have some diagrams related to the wiring to this?

Sabino56

I only know enough about the VSSB (or maybe actually DRAC on 93’s?) to know that there are a lot of variations, types of VSSB/DRAC, ability to jumper inside to set calibration, etc. if someone doesn’t come along who knows with confidence you may want to go to gearhead-efi where the tuners on these vehicles know the details. GM EFI Systems. Search on VSSB/DRAC and you may find some help. Sorry I can’t help

Gumby22

Not trying to split hairs here but details are going to matter in order to get this sorted out.

A “K3500” would be 4wd - A “C3500” would be 2wd - so what was the original set up on the truck? Look at the 5th digit of the VIN - that will confirm.

Do you know the year of the donor engine and transmission?

Namu

I specified it was originally 2wd. As far as I'm concerned it's a k3500 because it now has a transfer case. I had no part in swapping the engine and transmission and I do not know anything about it.

Little Bear

I think in 93 there was still a small plastic box behind the glove box that had jumpers in it to calibrate the speedometer, I had to replace one in my 92. Pull out the glove box liner and you should see it to the left of the box velcroed to the air box. Maybe there is an issue in that area.

Gumby22

Good luck then.

Sabino56

i think Gumby was asking details because you’ll need to know what the truck was born with to know what VSSB/DRAC is in the truck and you’re going to need to know transfer case & engine is in there now to know what mods are needed (if any). If you ask on gearhead those are the first questions you’ll likely be asked.