Transmission swap

Hello, My stepson has 92 c1500 pickup with 4L60 trans that had lost 3rd and 4th. He bought junk yard trans from 93 Cadilac Fleetwood and had a guy swap them. The dust cover was the minor issue but speed sensor maybe the big issue. Truck shifted and ran great for 1st 20 or so miles but without speedometer. We figured sensor may be bad and was going to swap it with old trans. Found that the old pickup trans has sensor that looks like an induction pickup sensor, while that Cadi trans has a shaft that spins driven of the tailshaft. Now he is get Check Engine light which I understand that the speed sensor connect to computer and no info being sent to it. Im looking at replacing sensor with a new one. Is there more to this? Will either sensor work with this truck?
Been a long time since I've dealt with anything that far back. I'm thinking you might have to swap the tail shaft from your old tranny along with the magnet or reluctor ring on the output shaft. Not even sure if they'll fit. Probably best to check with a tranny shop.
Thanks. I have always shied away from transmission issues. But last night I tore the tail cone off the old transmission. I was hoping yo remove reluctor ring to find that its pressed on. And I appears that to remove tailshaft involves much more.
I do remember that the speedo gear for the old cable driven speedo is a pressed on plastic gear. There should be a way to pull the reluctor.

And yeah, to replace the tail shaft to have to take the tranny out and basically pull the whole thing apart.

Digging way deep into my memory here, there might be a conversion kit to use the old gear driven speedo to an electronic one. Again, a tranny shop might have something.
Got it fixed. I cut output shaft off on the trans side of the 'Reluctance Ring' formally known as drive gear and took into my shop. (A/C in there, 101 outside) Using drill press I drilled holes around shaft near the ring and was able to drive the shaft out of the ring. Placed ring on a piece of sheet metal and he did it with a heat gun for about 5 minutes. Using a new pair of welding gloves I was able to slide it on new shaft with pipe and hammer with little effort. Have to be quick cause it cools quickly and shrinks back. Reassembled tail shaft and Speedo sensor and all is good. Caution welding gloves are not necessarily heat resistant. I know this now. The old plastic removes with releasing a clip and a little persuasion to get it moving. Thank you for your comments and calling enough transmission shops to get pieces of info on how to fix this helped out.


Well-Known Member
Thanks for the follow up, it's helpful when people solve a problem like you did and let us know about it :thumbsup: Mike.