904 slip-yoke
- Thread starter 68coupe
- Start date
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The yoke that goes in the trans?
The 904 is different from the 727, they will not interchange.
Do you need one?
The 904 is different from the 727, they will not interchange.
Do you need one?
No, don't need one. I'm looking at replacing the 7 1/4 with an 8 1/4 and figuring out what driveshaft will be needed. From research, I know that he can measure the existing driveshaft and subtract 1.25" from that to get the length of what is needed.
He's gonna have to drive 200 miles to my house for me to do the swap. Just trying to get everything lined up beforehand. Thanks
He's gonna have to drive 200 miles to my house for me to do the swap. Just trying to get everything lined up beforehand. Thanks
fishy68
Tyr Fryr's Inc.
Don't quite understand your question. All 904 yokes have the same spline count. If your asking what U-joint it is it should be a 7260
OK, here's the rest of the story. I changed my 7.25 out for an 8.25. I knew that I needed to shorten the driveshaft to account for the differences in the required length. A fellow had a bunch of Mopar parts advertised on Craigslist for months, including a driveshaft.
I measured and came up with the required length for the driveshaft and the one on CL matched my required length. So I bought it for $20. When I tried to install it, it was too long. Then I put it side by side with the old driveshaft and the transmission yoke was quite a bit longer. I changed the yokes and it worked perfectly. I was told that the driveshaft was from a 78 Aspen. It's the same as the 68 Barracuda shaft, only longer.
I may do the same rear end swap for a friend and was trying to be proactive about some of the issues we will also have with his car. Since he is having to drive 200 miles, it would be nice to have these issues handled beforehand.
Thanks, guys
I measured and came up with the required length for the driveshaft and the one on CL matched my required length. So I bought it for $20. When I tried to install it, it was too long. Then I put it side by side with the old driveshaft and the transmission yoke was quite a bit longer. I changed the yokes and it worked perfectly. I was told that the driveshaft was from a 78 Aspen. It's the same as the 68 Barracuda shaft, only longer.
I may do the same rear end swap for a friend and was trying to be proactive about some of the issues we will also have with his car. Since he is having to drive 200 miles, it would be nice to have these issues handled beforehand.
Thanks, guys
Trans yoke should only have about 1/4 inch from the end of the bellows seal, to the yoke. that is going to be sticking out over an inch if you don't have a bellows type seal, not all use them. Stock had them but you can get without. MT
fishy68
Tyr Fryr's Inc.
I don't mean to be rude but that doesn't make sense. I have had several 904 yokes and while there was some very minor difference in lengths in them (no more than 1/2") they always bottomed out to the same depth in the trans., therefore the total length made no difference in the end
Well, yeah - they are all gonna bottom out at the same depth. But......the difference in these two yokes was in inches, not fractions.That's my question, why so much difference in length?. When I put the driveshaft with the 78 Aspen yoke in the transmission, it bottomed out and the rear joint would not go into the rear yoke. I had measured very carefully between center to center on both shafts. :scratch: When I put both shafts on the bench I noticed the Aspen shaft was much longer due to the front yoke.
Put the Barracuda yoke on the shaft and everything worked perfectly. Just curious about the different lengths.
Supershafts
Well-Known Member
There are several insanely long variations of slip yokes.
Which is why i say BOTTOM the yoke out and then measure center to center and let the driveline shop determine your travel.
Some are 6", 7", 8", 9" long
Which is why i say BOTTOM the yoke out and then measure center to center and let the driveline shop determine your travel.
Some are 6", 7", 8", 9" long
So, I guess they are different just cause they wanted to make them different! Thanks
Oh, one more question. If you had a much longer yoke like I did, could you just have a machine shop cut off and redress the yoke instead of cutting, rewelding and balancing a driveshaft? I just happened to have the shorter yoke on the old driveshaft.
Supershafts
Well-Known Member
You could trim off some of it, also some of the older trans used to use a o-ring and the slip would be on that o ring, as time went on and they got away from it, the company doing the shafts (detroit) didn't bother to waste slips and continued using them.
Same as when mopar got away from parking brake and the trans going to the parking pawl and causing the trans fluid circulation problems for the next 20 years or so before they corrected it. . . .
Same as when mopar got away from parking brake and the trans going to the parking pawl and causing the trans fluid circulation problems for the next 20 years or so before they corrected it. . . .
383Scampman
Well-Known Member
Easy way: use your front yoke. After the 81/4 is in car AND secure AND at ride height insert yoke in trans. Pull out 11/2", measure center line of yoke to center line of u-joint on 81/4 rear. THAT is how long your shaft needs to be center to center. Cut shaft to length, weld together, BALANCE, install, go home, BE SURE cutting welding, balancing is done by a professional that has the equipment to do this. Some auto machine shops that make truck driveshafts have this equipment. Oh, I forgot, the u-joints MUST be "in phase" or it will vibtate. Thus a professional, good luck
383Scampman
Well-Known Member
vibrate not vibtate, sorry
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