727 Difference inside

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coyote42

coyote42

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Transmission gurus,
I have a Big block transmission from a motor home and one from a C body. I see on the MH one there are ribs on the tail shaft for strength, C body smooth. Are there any internal component strength difference between the two? I want to build one and sell the other with a 68 383 I will be listing.
Thanks!
 
Need to know the years of the transmission's first. The motor home 71 and later usually has four clutch drum and four pinion planetaries. May have a different governor to make it shift a little later. May also have a hard not flexible band and usually have a 3.8 lever. And of course, the better tail shaft housing (snap ring for bearing on the side instead of by the trans mount. If they are both 71 and later, they both have the better front pump (for wide bushing drum) that's about all I can think of off the top of my head. If you truly have a 68 transmission sell that one and keep the motor home to build! Hopefully this helps.
 
Also keep in mind that the motor homes also came with a different tail shaft from the cars because they had a large 11”x 3” drum brake used as the parking brake.
Output shaft will need to be swapped out with a car or 2wheel drive pick up output shaft to use the car style tail shaft.
 
Tailstock, not tailshaft. Only place ive ever seen one crack is at the bushing area, whilst pushing a new bushing in.

Post up the PK numbers on the pan rail on the drivers side.... with those numbers we can tell how robust the internals are.
 
SMCARNUT said:
Need to know the years of the transmission's first. The motor home 71 and later usually has four clutch drum and four pinion planetaries. May have a different governor to make it shift a little later. May also have a hard not flexible band and usually have a 3.8 lever. And of course, the better tail shaft housing (snap ring for bearing on the side instead of by the trans mount. If they are both 71 and later, they both have the better front pump (for wide bushing drum) that's about all I can think of off the top of my head. If you truly have a 68 transmission sell that one and keep the motor home to build! Hopefully this helps.
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Don’t know the years of the trans. The engine came separately and is a 68
 
Syleng1 said:
Also keep in mind that the motor homes also came with a different tail shaft from the cars because they had a large 11”x 3” drum brake used as the parking brake.
Output shaft will need to be swapped out with a car or 2wheel drive pick up output shaft to use the car style tail shaft.The MH trans has a regular tail shaft. No brake drum.
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The MH trans has a regular tail shaft. No brake drum. Both look the same except the MH has ribs on the housing.
 
coyote42 said:
Don’t know the years of the trans. The engine came separately and is a 68
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2801541-67-68 8-440 HiPer.jpg


The part number is on the pan rail. It can be matched to a chart available here: http://www.mymopar.com/downloads/transguide.pdf Or post it here and I'll look it up. It will tell you year and application.
 
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coyote42 said:
Found the 402 number in the list 76/77 400 non hp
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Made on May 14, 1976.

The other was made Oct 30th, 1972. I dont see the exact application for the other one either.... Seems to be a truck trans, is this the motorhome one??
 
The other trans came up as 73 truck bb trans when I put 3732534 in as the number. It did not come up with any other apps when plugging in any other number but 534. Kind of goes along with the above post saying Oct 30,72.
 
Lefty71 said:
Made on May 14, 1976.

The other was made Oct 30th, 1972. I dont see the exact application for the other one either.... Seems to be a truck trans, is this the motorhome one??
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Yes That is the supposed Motor home one. The 1976 one is from a C body I was told.
 
S'cuder said:
Sorry to be so late to chime in. I'm agreeing with the others on the 373 trans. It's not in the application chart I listed, and I don't have access to a 1973 truck parts manual. But Google sources call it in favor of that.

Is it snowing there yet?
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We got a little. South of me got over a foot.
 
coyote42 said:
We got a little. South of me got over a foot.
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Just a few flakes in the air here in my area on the south shore of Lake Ontario.

I used to sell oil to Falkner's and Randy's, but both have been sold out since then.
 
Hello
Not wanting to butt in but splines on the output shaft changed as well. It’s been a bit since I searched it but 77 definitely has the later spline angle. The old parts will install but the trans will not stay together if you use the early shaft in late parts.
So use the late trans for the stronger internals and the tail housing from the early but you have to find the right output shaft.
 
AbodyBB said:
Hello
Not wanting to butt in but splines on the output shaft changed as well. It’s been a bit since I searched it but 77 definitely has the later spline angle. The old parts will install but the trans will not stay together if you use the early shaft in late parts.
So use the late trans for the stronger internals and the tail housing from the early but you have to find the right output shaft.
Click to expand...
Ok, I never heard about the tail shaft difference. Does it bind when you combine parts? What breaks?
 
What AbodyBB is talking about, is the front planetary splines to the front output splines. A lot of guys changed from a 3 pinion to a 4 pinion planetary and did not match the splines. It would work ok for a short time, then rip the splines right out of the planetary or break it into a couple of parts. You will know that it is wrong match if you try to wiggle the planetary on the output shaft and it acts like it may be worn a little. It has to fit tight. Ask me how I know.
 
There are three different spline angles in the 727 front planetary.

The spline included angles are as follows:

'62-'75= 90°

'76-'93= 75°

'94-on= 60°

The spline angles are sometimes expressed as the pressure angle which is half the included angle (45°, 37.5°, 30°)

Each change affected the diameter of the splines so smaller shafts will fit in larger planetaries but the loose fit will lead to early failure.


Copied form an old Moparts post (John Kunkel)... just make sure you keep the proper vintage shaft with the proper vintage planetaries and you'll be fine. I would advise you pick up the two common 727 rebuild books available.... look up authors Tom Hand and Carl Monroe. Their books should be read and understood before attempting to swap parts, IMO.
 
Thanks all. These are the bits I wanted to provide but hadn’t time to provide.
I found the right shaft for long shaft 727 from cope racing transmissions. The original output shaft housing was 18 5/8.
 
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