Driveshaft length

syrupdawg

syrupdawg

GA Diesel Mafia
Joined
Mar 16, 2008
Messages
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I have a question for some people that are more knowledgeable than I am with driveshaft stuff. My wifes Fummins is almost done and I need to get the rear driveshaft done. I really want to get the rear driveshaft made into a one piece instead of using the carrier bearing.

We measured last light and from yoke to yoke it is 74 3/8th" on the ground. When you figure in the you joint yokes it makes the driveshaft tube about 64". Is that too long? Keep in mind there will be a slip joint in it also. The truck should be in the 800hp range and will be sled pulled and drag raced.

I also want to get rid of the constant velocity on the front end. The truck is not lifted and the front driveshaft is at a nearly straight angle. Probably only 5* or so. Is that a good idea or should I leave it.

I am going to go ahead and build driveshaft loops for it regardless but would prefer not to have to use them!
 
I can't give an expert opinion on it, but the one I did get was that it would never work. The driveshaft shop outright refused to make it. I know its not nearly the same with slower shaft speed, but the one in my pulling truck is almost the same length, and has been fine all year. Can you do it? Yes. Do they recommend it? Nope. If you can get someone to make one and balance it, try it out.
 
64" does not seem like a very long shaft. Lots running crew cab long bed trucks with a single shaft, has to be wayy over 64". I know there is a certain point where you need to switch to a large O.D aluminum shaft vs steel. I would defiantly get rid of any carrier bearings and just run a straight shot from tcase to diff. Unsure about removing the constant velocity joint...
 
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Okay well by the time I put a slip joint in it the actual longest part of the shaft probably will be less than 50". Or does the slip joint figure into the overall length
 
I found that most drivelin shops would touch anything one piece needing to be over 75" center to center of u joints. At 64" you should be fine!
 
I have shafts at 90", material and diameter will dictate what you get and other parameters.

yoke to yoke is a useless measurement in a 2 pc set up. The suspension movement is being done after the hanger bearing, the 1pc will do it at the trans or Tcase.

You need the seal to center or seal to face measurement and the driveline shop will determine the c to c length.

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