I have a 85 5 speed tranny i want to put in my auto 79. Will all i need to do is a tail houseing swap? And if so what year tail houseing does anyone know


Thanks shane

 

There are many post on the forum where people have done a 84-85 (FB) trans swap in to a 79-80 (SA). You just can't swap the tail. You will need to shorten the shifter bar.

You will also need the 79/80 pedals, pedal sensors, trans cross member, clutch master and slave, and 79 flywheel/clutch, and possibly the speedo cable.

 

Actually, if you can find a late production 1980 5-speed box (birthdate 3/80 and newer, I think) you CAN swap the tailhousing. You couldn't physically move the FB shift tower to where it fits in an unmodified SA, and there's something different about the early smoothcases where they are not cross-compatible with FB.

When you swap the tailhousing SA to FB you also have to change the shift fingers because the shift rod is in a different location on the two tailhousings, so the shift fingers are designed for a different arc of motion. Early SA have bolt-on fingers while the late SA and FB (and FC and Miata and...) use roll-pins. I never checked but it looks like the case bolt pattern may be different early vs. late as well.

But I have done the opposite swap - FB tailhousing onto a late SA 5-speed for my '85.

If you are able to do this, make sure to keep the speedometer drive and driven gears as a matched set. The pitch changed in '81-82ish.

 

Well, I have considered a similar swap. from '79 smooth case to something a little stronger. However, years ago, I had the tailshaft built up and bored out to fit RB's rollerbearing setup and had a new, balanced, dampered (if that's a word), and lubricatable (another one of those) U-joint drive shaft.
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I have left the interior stock except for gauges and radio and want to keep it that way.
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Suggestions??