727 driveshaft

I just finished putting a Strange S60 rear end in my 65 Coronet. I was told that it only came with a yolk for the 1350 u-joint, and they did not offer the 7290 yolk. I then ordered a driveshaft from someone else( Name withheld till I find out what is going no), and it came today. One look and I knew something was wrong, the front slip joint looked too short and the splines come all the way to the end of the slip joint.

This is a 65 Plymouth Fury cable shifted 727, with the slip joint. I don't know much about Mopar driveshafts, but I have never seen one that didn't have an unsplined area in the front of the slip joint. This is necessary on my transmission as there is a seal on the output shaft that rides in the unsplined area of the slip joint.

My question is did the newer driveshafts not have this unsplined area on the yolk, or did the company that built the shaft mess up? I did a quick measurment on the new shaft and the slip joint is aprox. 4 and 1/2 inches, and my old one is about 6 inches. I have not tried to put it in as there is not much point, so I don't know if the spline count is right, but the invoice shows it is for a 727.

I tried to call the company where I ordered the shaft, but they were already closed, so I get to fume over this all weekend.

Any help deeply appreciated.

Take off the shocks at the axle and lift the pumpkin with the shaft installed with a floor jack. You need a 1" clearance on the trans seal/yolk at the top of the axle travel. Use grease on the splines for witness marks.

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Sorry, I could show you better than telling you on the web. Next,

Sorry earlybee, My post wasn't very clear. My question was about the front yolk on my driveshaft, where it slides into the transmission. The tube part of the yolk is splined all the way to the end. My old one, also bought from the same company, has a unsplined area about two inches long before the splines start. Have you ever seen a front yolk for a Mopar with splines all the way to the front end of the tube. I wish I had a digital camera so I could post pictures.

As long as the yolk doesn,t bottom out with at least 1" outside seal/inside spline clearance, to spare from full spring compression/ axle wrap up, Or lose less than 2-3" of spline contact fully extended, IMO, your golden. Use grease on the splines to see the full, witness mark, range. My custom cut shaft/ yolk for a 440/727/dana in a 65 b-body is fully splined inside. no probs yet. http://good-times.webshots.com/photo/2540015580103482066ymkoSt

Thanks earlybee. I will take your advice and check contact area today.

My first thought was that without the unsplined area at the front of the yolk and the seal on the transmission output shaft being employed, that the area between the end of the output shaft and the rear of the yolk would fill with fluid and somehow cause a problem. After calming down overnight and thinking about it, I can see where the seal might not be necessary.

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As long as the yolk doesn,t bottom out with at least 1" outside seal/inside spline clearance, to spare from full spring compression/ axle wrap up, Or lose less than 2-3" of spline contact fully extended, IMO, your golden. Use grease on the splines to see the full, witness mark, range. My custom cut shaft/ yolk for a 440/727/dana in a 65 b-body is fully splined inside. no probs yet. http://good-times.webshots.com/photo/2540015580103482066ymkoSt

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Easy way to check this is to inset the drive shaft and measuring from the rear end yoke push the drive shaft forward till it bottoms out in the transmission. Measure the distance it traveled forward from the rear end yoke. 3/4-1 inch is good. Don't use the seal as a measuring point, let it collapse while measuring.