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Hey everyone, I need help finding the correct part number for the speedo drive gear housing, I recently swapped rear diffs and went to swap over the speedo drive housing and gears to match only to find the housing was broken. I tried the housing original to the car and it was too long for the drive gear shaft. I ordered a TCI unit for 40 to 43 tooth drive gears... also too long. I then got an AC Delco unit for 36 to 39 tooth drive gears... also too long. anyone know what part number I need?
left to right: TCI, stock '84, stock '86, AC Delco. top: stock '84, and stock '86 gears.
you can see the difference in the shaft length from the old (blue) to the new (red).
The gear/sensor on the left are for an 'electric' speedo, & the parts on the right are for a 'cable' speedo. Both are for correct for a red 37 tooth DRIVEN gear.
The ROD/shaft for the cable VSS, 34-39 tooth, DRIVEN gear is shown as 76.5mm.
Notice the inside of the DRIVEN gear. The Cable type gear has a raised "neck" on the inner side of the gear while the electric version of the gear has no "neck" on the inside. I'm guessing that you either have the wrong shaft,..... of the wrong type of DRIVEN gear.
Thanks for that info. This keeps getting stranger and stranger... the gear, housing, and rear diff all came from my old '86 which was a cable driven speedo. I'm swapping it all into my new '84 which is also cable driven. I know it all was cable driven because I forgot to disconnect the cable when I dropped out the tranny of the '86 and that's how the housing got broken.
I found a fully plastic 37 tooth gear on Summit from TCI. It doesn't give any measurements but it has the plastic shaft instead of the steel... that may be the way I'll need to go with this.
If it helps at all the '86 was a 2.8l + 700r4, and the '84 is a 5.0l + 700r4. I know the v6 bellhousing were different so maybe the drive gear and housing were also odd?
