727 output shaft question

[d55dave]

I am working on a friends torqueflite and have a question. What I am starting with is an early 80's non lockup 4X4 727 that has been built into a big block main case (the case is a 70 or 71 vintage) All the internals appear to be early 80's 318 truck parts, nothing special. The transmission was recently rebuilt and working fine, but needs to be converted from the 4X4 configuration to a passenger car long tailshaft slip yoke style for use in a 70 Barracuda.

I understand that the spline design on the front of the output shaft changed in 1976. I have a complete 1968 318 2 wheel drive truck transmission that I would like to use the tail housing and output shaft from. Can I use these in conjunction with the early 80's internals and earlier big block main case? What other parts do I have to swap along with the shaft and tail housing? I suspect at least the rear planetary, anything else?

Thanks for any help.

 

[Bb70charger500]

Not to shure , sounds like it would work doesn't hurt to take them appart and try. I'm not to shure your going to get an answer on this here ,you could see about a rebuild kit run both years and see if the part numbers are the same that would be a start if know one else knows . Hopefully someone will give you an answer if not try the part number thing it's worked for me before .good luck

 

[d55dave]

Thanks for the answer. As I said there was a change in the spline design but I am fairly certain that I can get away with just using the output shaft, housing and rear planetary from the 68 transmission. Unfortunately I don't have access to torqueflite parts books

 

[mopar 3 B]

My book only covers 69 - 79. From what I have found powerflite 727's used the heaver planetaries using all the 68 parts would be the surest fit.

 

[Greg Ducato]

The front planet is the one that is splined into the shaft, the rear planets will interchange. The 318 units used a 3 pinion front planets by and large which you may want to upgrade to a 4 pinion on a big block

 

[dvw]

Keep the front planet and output shaft together. Then you'll be fine. No need for 4 pin planets. I run 9.20's@3340lbs on a 3 pin.
Doug

 

[d55dave]

Thanks for the info guys. Yes, front planetary is what I meant as it is splined to the shaft. Is this the only spline whos design changed in the mid 70's? Is the one on the output shaft for the rear annulus gear assembly the same on all torquflites irregardless of year (66 and up)?

 

[mopar 3 B]

This is what is stated in the 69 - 79 Torgue Flite Transmission Field Service information manual.
1976 Model Year
A-727 Output Shafts & Front Planet Pinion Carrier (All A-727)
The internal 28-tooth spline in front planet pinion carriers and corresponding spline on the output shafts were changed from a 45° pressure angle to a 37 1/2° angle. This change was made to add strength to the carrier spline. The new carriers and output shafts are not interchangeable with prior model years. However, the new carriers and shafts, if used together, could be used to service prior model transmissions.

As stated before I do not have the service info after 79 to determine if later 80's parts will enterchange with 78 & 79 inerds.