C6 Rebuild/Interchangeability Question

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Apr 28, 2018 | 06:24 PM

sinnedspeedshop

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C6 Rebuild/Interchangeability Question

I'm in the process of rebuilding a 1975 FE C6. The tail shaft is not usable. Could I use a 1968 FE C6 tail shaft on the 1975 C6?

Any help will be appreciated.....thx.

Apr 28, 2018 | 06:33 PM

Filthy Beast

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DON"T throw the unusable tail shaft out! I believe a '68 tailshaft won't work.....length differences. By how much, I'm not sure..that's why keeping the old tail shaft comes in....measurements, and all.

Someone will come along, I'm sure, with better information than me....good luck.

Apr 28, 2018 | 06:34 PM

NumberDummy

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From: Simi Valley, CA

Quote:

Originally Posted by sinnedspeedshop

I'm in the process of rebuilding a 1975 FE C6. The tail shaft is not usable. Could I use a 1968 FE C6 tail shaft on the 1975 C6?

C6 from a 2WD or 4WD?

Apr 29, 2018 | 05:30 AM

Crop Duster

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From: Tri Cities, TN

Quote:

Originally Posted by sinnedspeedshop

I'm in the process of rebuilding a 1975 FE C6. The tail shaft is not usable. Could I use a 1968 FE C6 tail shaft on the 1975 C6?

Any help will be appreciated.....thx.

If the shaft is identical from the distributor to the end. As in the picture it should work fine. The picture is a 74 T-Bird shaft and is just for illustration. Just happened to be the only one I had laying around. But since you have that thing tore down that far I would recommend the kit in the second picture. It happens to be a Ford part but they are available aftermarket. Replacing that #9 thrust washer with a needle bearing frees up a lot of horsepower loss in a C6. Also be sure and count the speedometer drive gear teeth on whatever shaft you use in case they aren't the same so you will know which driven gear you need to make the speedo work correctly.

Apr 29, 2018 | 06:43 AM

sinnedspeedshop

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Guys, I apologize. I had my head up my butt when I said I wanted to use a 68 FE C6 "tail shaft." I meant I want to use the 68 C6 tail shaft HOUSING on the 1975 FE C6. So just the housing....not the actual tail shaft. Both C6s were from 2WD trucks. Thank you.....sorry about my error!

Apr 29, 2018 | 08:37 AM

Crop Duster

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If it's the same length and has the correct mount on it, should just bolt right on. There were several different extension housings and it was common practice to swap them to make the trans fit in different vehicles.

Apr 29, 2018 | 09:52 AM

NumberDummy

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From: Simi Valley, CA

Quote:

Originally Posted by sinnedspeedshop

1968 housing will not work on a 1975 trans.

The extension (tailshaft) housing length has to match the output shaft.

1968/72 F100/350 output shaft is D1TZ-7060-A (replaced C8TZ-7060-A) .. 17 5/16" long, 25-34-36 teeth, 10 splines. Speedometer DRIVE gear on shaft is replaceable.

1973/79 F100/350 2WD output shaft is D6AZ-7060-A .. 23 3/16" long, 25-34-36 teeth, 31 splines, Speedometer DRIVE gear not replaceable, as it's made as part of the shaft.