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Driveline issues

goose69

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Ok I feel pretty stupid here. I have a 1966 belvedere I am building. I removed the original non-poly 318 and 727. I built a 440 for it and bought a '78 Dodge 2wd pick up for cheap and it had many speed parts on it I am using. One of the parts that I am trying to use is the 727 that was in it. It was built by a local guy who puts together some really nice transmissions.
Problem: I cannot get any of my drivelines to work, none of the splines seem to match up. The outer diameter seem correct as the yolk slides in past the seal but as soon as the splines hit….nothing meshes. The original driveline along with one out of a 1967 big block 727 satellite won't work. I also have one out of my 1969 Roadrunner that I tried and the same thing happens. Is there something I am missing here as I was under the assumption that all 727 output shafts were the same. This trans came out of a 2wd standard cab short bed truck so I thought it was the same. Only difference I saw was that the output shaft stuck out farther out of the tail housing of the transmission.
Anyhows, any clarification on this would be greatly appreciated.
 
Hmmmm, odd. Start by measuring the OD of the output shaft with calipers and counting the splines. Then count the yoke splines or compare to the tranny you removed. I am not aware of a special output shaft for a truck. 904 and 727 have different output shafts.
 
Well I went out and looked over some things. First I counted the output shaft splinters and yep, there is 30. Then I went to measure the shaft. My mics had dead batteries but just put them on the shaft and then walked over to the other 2 727 trans. Same size. Ok so why are these slip yolks not working? The splines look a little sharper tho. So is it possible someone put an a518 output shaft into a 727 case? Haven't tried that slip yolk yet. Anyways, before I installed this trans I put in a new filter & gasket so it couldn't be an a518 cause the 727 parts went right on.
So I will try & post a couple pics here too.
 

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As I have been told and have experienced, the key ways don't have to match any particular place in the splines. I confirmed this by installing slip yolk on other transmissions and trying different clockings, slips in wherever I put it.
 
Could be tight tolerances.... or a slight twist in the splins... some have to be lined up though.... its odd it doesn't fit. Try a little emery paper to see if its just tolerances.... it needs a little immeasurable but some..
Try a small file to feel if the end has swollen form being dropped.. just the end to get it on but YOU SHOULDN'T HAVE TO PRESS IT ON..got to be frustrating...
 
File on what? The transmission output shaft or the slip yolk? Now keep in mind I have 3 different 727 slip yolks and none of them will go onto this transmission but slip fine onto my other 2.
 
It's a little hard to see but it looks like there is something going on just inside the tailshaft housing or the splines are short. just can't see it well in the pic.
 
File on what? The transmission output shaft or the slip yolk? Now keep in mind I have 3 different 727 slip yolks and none of them will go onto this transmission but slip fine onto my other 2.
The shaft ... the last 1/4" make the groves deeper and sharper a little incasee it got rounded... as long as it goes on all the way the end doesn't matter

- - - Updated - - -

The shaft ... the last 1/4" make the groves deeper and sharper a little incasee it got rounded... as long as it goes on all the way the end doesn't matter

You got nothing to loose with it.. something is swollen or rounded or just wrong
One little flat spot will hold you up
 
File on what? The transmission output shaft or the slip yolk? Now keep in mind I have 3 different 727 slip yolks and none of them will go onto this transmission but slip fine onto my other 2.
With that statement, it tells me there is something wrong with the OUTPUT shaft on the transmission. Or I suppose it could be the slip yoke bushing. Remove the extension housing, and see if the slip yoke will go onto the splines with the extension housing off of there. Also see if the slip yoke will fit into the ext housing bushing. That should show you where the trouble lies.

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There are 5 bolts that hold it on. And there is a snap ring under the plate that is under the trans mount. I just took one off of my 65 Belvedere today. Easy to do with it in the car.
 
The shaft ... the last 1/4" make the groves deeper and sharper a little incasee it got rounded... as long as it goes on all the way the end doesn't matter

- - - Updated - - -



You got nothing to loose with it.. something is swollen or rounded or just wrong
One little flat spot will hold you up

First off I want to thank all of you who chimed in to help me with this dilemma. I appreciate it greatly.

Sleepar,
Thank you for your suggestion of filing the end of the output shaft. I decided this evening while looking at it that it couldn't hurt to try this. I found a fine, triangular shaped file and went to town on all the splines. Then I touched up the outer diameter of the shaft. Holding my breath I took my loose slip yolk I had lying beside me and "SHOOP" it slid right on!!! Man that was great to see. It sure saved me a lot of other grief I was about to embark on. So yes boys and girls even a little bit of discrepancy on the splines can make a huge difference. With that done and the driveline back in I only have a couple other things to do before I fire up the new motor in the car! I am getting very stoked now!
Thank again to all that helped.
 
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