Here's a picture of the plug I removed, it actually looks like a factory part.
I put my pinky finger into the hole, front, back all around, there is no gear or evidence there ever was one in there, I guess I'll call the trany shop tomorrow.
What I mean by compatible is, does the hole for the speedo gear line up with the gear machined into the output shaft? The two options based on the evidence here are that the gear doesn't line up or that it is missing. Either way, it's an issue that needs to be addressed.
1967 F100 SWB
1991 Thunderbird 5.0 with fully ported gt40 heads, cobra intake (also ported) and a trickflow stage 2 cam, manual steering, and custom 3" exhaust
There is "no gear" in the transmission, it's a smooth shaft as far as my pinky finger can feel in every direction.
It seems to be the same size as the drive gear in the tranny I pulled.
You definitely have a problem. You are going to have to pull your extension housing to see if- #1) There is any gear machined into the output shaft. #2) If there is, can you get an extension housing that has a speedometer hole that lines up with the gear. #3) If there is no gear, you need a different output shaft.
1967 F100 SWB
1991 Thunderbird 5.0 with fully ported gt40 heads, cobra intake (also ported) and a trickflow stage 2 cam, manual steering, and custom 3" exhaust
I just talked to the transmission shop, he said some of the early shafts didn't have the gear machined. The trans would have to come out and be redone, the output shaft is the first part to go in the case when rebuilding the unit.
I'm trying to find a different solution, is there a electronic speedo that I can use that is not driven off the gear?
Before you start trying to find an exotic solution, you should take the tailhousing off (this will need to be done whatever solution you decide on) and check for the gear. You may have a mismatch of parts.
1967 F100 SWB
1991 Thunderbird 5.0 with fully ported gt40 heads, cobra intake (also ported) and a trickflow stage 2 cam, manual steering, and custom 3" exhaust
granted i have no idea how any of this goes together, but don't some of them pull the speedo drive off the T-case? maybe you have parts from a 4wd with the speedo meant to go into the t case so the speedo drive in the trans is blocked?
I live in Arizona, purchased the tranny out of Florida shop (Transdepo). Yes the guy said he would make good on it, but I really don't want the project to move backwards. I would rather come up with a fix rather than sending it to Florida for a new shaft.
I personally am not aware of an electronic speedometer that will work on a C6. It is hard sometimes to go backwards, but you may be able to negotiate with the shop and get some of your money back for your inconvenience.
1967 F100 SWB
1991 Thunderbird 5.0 with fully ported gt40 heads, cobra intake (also ported) and a trickflow stage 2 cam, manual steering, and custom 3" exhaust
Perhaps a gps speedo, also there are sensor speedos like the use on motorcycles, I could probably rig something up. I was thinking about do a custom instrument panel anyway. It will cost me more to convert but I can see this dragging out for months longer if I send the transmission back.