727 Question

[old school]

Hello Guys
This may be a dumb question but here goes. Do all 727 transmissions have the same tail shaft? If not what sizes and lengths do they come in? I have a 74 duster with a 360 and a 727 that came out of a dodge r//v. I've installed a 8 3/4 suregrip and I now need to get a drive shaft for it. but what I see on line the measurements don't match up.
Any suggestions?

Thanks
Old School

 

[bad440]

Hello Guys
This may be a dumb question but here goes. Do all 727 transmissions have the same tail shaft? If not what sizes and lengths do they come in? I have a 74 duster with a 360 and a 727 that came out of a dodge r//v. I've installed a 8 3/4 suregrip and I now need to get a drive shaft for it. but what I see on line the measurements don't match up.
Any suggestions?

Thanks
Old School

how long does it need to be,mine was around 58 inches

 

[old school]

Tip to tip counting the yolk it's 52"

 

[67Dart273]

There's only one long shaft. They are a little longer than a 904, and your shaft is going to depend on what rear axle you've got. As old as these girls are, I'd NEVER take anything for granted. Some cars, like my 67, really should have the axle moved to the rear an inch or a little more, so if somebody DID that, none of the factory length shafts you find are gonna fit, anyhow.

The rest are very short as in some motorhomes, or the adapters that hook up (bolt to) transfer cases in 4x4's and some heavy/ truck units that had the torque multiplier or whatever it was called.

 

[crackedback]

Can't say it will help much, but are you sure there isn't a gearvendors or transfer case attached?

 

[fishy68]

Tip to tip counting the yolk it's 52"

By this description I'd guess you have the RV type that uses a 2 piece driveshaft and has a short output shaft with a yoke bolted directly to it and possibly a transfer case or some other gear box also bolted to it and maybe even a parking brake assy. Not a slip yoke style output shaft like a car uses. Correct? If so it won't work in your car unless you completely disassemble it and replace the output shaft and extension housing assy. with car/light truck parts. The output shaft comes out through the front, that's why it has to be completely disassembled to shange it.

 

[old school]

Thanks all
I worked the problem out it has a regular 727 with a regular yolk and no break mounted. I just took the drive shaft to a shop and had it cut. Went to napa and bought a u joint that was 2 different sizes. The rearend is a 8 3/4, the shaft was for a old 7 1/4 but it all worked out fine. the u joint number if anyone ever needs to mate these two odd sizes is a presicision #308 The two sizes are 2 1/8" and 2 5/8" with 1" cups on both sizes.
Thanks for the info guys.
Old School

 

[fanofpetty]

The proper drive shaft length for a duster with a 727 and an 8 3/4 rear would be 45 inches center to center of the u-joints.

 

[fishy68]

Thanks all
I worked the problem out it has a regular 727 with a regular yolk and no break mounted. I just took the drive shaft to a shop and had it cut. Went to napa and bought a u joint that was 2 different sizes. The rearend is a 8 3/4, the shaft was for a old 7 1/4 but it all worked out fine. the u joint number if anyone ever needs to mate these two odd sizes is a presicision #308 The two sizes are 2 1/8" and 2 5/8" with 1" cups on both sizes.
Thanks for the info guys.
Old School

Just courious what do you mean by a "regular yoke"? The type that's on a rearend that the u-joint bolts solidly too or a slip yoke that slides into the trans.?

 

[fishy68]

The proper drive shaft length for a duster with a 727 and an 8 3/4 rear would be 45 inches center to center of the u-joints.

That can actually vary a little bit depending on the slip yoke used. Some slip yokes slip farther into the trans. than others and some are pretty shallow. That's why you always need to measure it with the slip yoke your using.

 

[fanofpetty]

That can actually vary a little bit depending on the slip yoke used. Some slip yokes slip farther into the trans. than others and some are pretty shallow. That's why you always need to measure it with the slip yoke your using.

Now think about that....if your using an incorrect slip-yoke (to short), that simply means that yoke is not on as much spline on the tailshaft. Buy using a slightly longer drive shaft, ( like your suggesting) to try and compensate, is not the proper way to correct this, as your making the yoke closer to the end of the tail shaft and can actually bottom out with suspension travel causing damage. I'v seen this happen. You should always use the correct specified drive shaft length for the car, and the correct length slip yoke.

 

[fishy68]

Now think about that....if your using an incorrect slip-yoke (to short), that simply means that yoke is not on as much spline on the tailshaft. Buy using a slightly longer drive shaft, ( like your suggesting) to try and compensate, is not the proper way to correct this, as your making the yoke closer to the end of the tail shaft and can actually bottom out with suspension travel causing damage. I'v seen this happen. You should always use the correct specified drive shaft length for the car, and the correct length slip yoke.

I have thought about it and made precise measurements. Not just read stuff online and took it for granted. Think about this, lets say you have a yoke that goes farther into the trans. than another and you push it in and pull it out 1" and do that with another yoke that's 1/2" shorter how could the driveshaft bottom any easier? After all you've pushed both all the way in and pulled both out 1", right? You must not be aware but Chrysler used more than one length yoke from the factory. If you look down inside of different yokes you can see that some have the splines starting quicker, some start within 1/2" of the i.d. of the yoke, while others have an inch or more before the splines even start yet they both have approx. the same length of splines. I'm talking factory Mopar stuff, not aftermarket parts. Why Ma Mopar did that I don't know but I have seen it. Ask any GOOD driveline shop and they'll tell you there is no absolute rule that says a certain car has to have a certain length driveshaft because there are variables that can affect things.

 

[fanofpetty]

I have thought about it and made precise measurements. Not just read stuff online and took it for granted. Think about this, lets say you have a yoke that goes farther into the trans. than another and you push it in and pull it out 1" and do that with another yoke that's 1/2" shorter how could the driveshaft bottom any easier? After all you've pushed both all the way in and pulled both out 1", right? You must not be aware but Chrysler used more than one length yoke from the factory. If you look down inside of different yokes you can see that some have the splines starting quicker, some start within 1/2" of the i.d. of the yoke, while others have an inch or more before the splines even start yet they both have approx. the same length of splines. I'm talking factory Mopar stuff, not aftermarket parts. Why Ma Mopar did that I don't know but I have seen it. Ask any GOOD driveline shop and they'll tell you there is no absolute rule that says a certain car has to have a certain length driveshaft because there are variables that can affect things.

Ya, I'v seen different length yokes as well, and your right, as long as you leave some room for travel, for the slip yoke to move, you would be ok, but to simply use a longer than factory specified drive shaft, to make up for a shorter yoke is a bad idea.

 

[fishy68]

Ya, I'v seen different length yokes as well, and your right, as long as you leave some room for travel, for the slip yoke to move, you would be ok, but to simply use a longer than factory specified drive shaft, to make up for a shorter yoke is a bad idea.

Your right, that woudln't be the right thing to do. Not what I was meaning.