ArdWrknTrk Posted March 8, 2021 Share Posted March 8, 2021 That doesn't change based on tranny or transfer case? Good to know. I was looking more at my rear driveshaft situation. Will I need an engineering or physics degree to sort all that out? My existing rear axle looks like it has a different angle than a 4X4 would have had. Also, things look like they change at the transfer case compared to the 2wd tranny. Both trucks had the two piece shaft with the carrier bearing (which I think is labeled on the documents as a "two piece coupling shaft"?). Is it possible that I can just have a one piece built or is it preferable to stick with the two piece system? Pinion angle is set so that the universal at each end of the shaft should be cranked the same number of degrees. Otherwise opposite ends of the shaft are trying to travel at different speeds. This is one of the big reasons for companion bearings in a driveshaft. Link to comment Share on other sites More sharing options...
bp17oang Posted March 8, 2021 Author Share Posted March 8, 2021 Pinion angle is set so that the universal at each end of the shaft should be cranked the same number of degrees. Otherwise opposite ends of the shaft are trying to travel at different speeds. This is one of the big reasons for companion bearings in a driveshaft. Transfer case has a fixed yoke on the front and back. I think I'm following what you're saying about the pinion angles... My original thought was to just have the front section of the two-piece drive shaft shortened to accommodate the transfer case. The rear section shouldn't change in theory assuming that from the carrier bearing/fixed slip yoke back nothing changes I guess what I'm saying is I'm not sure if the height of where the yoke is on the transfer case is the same as the two-wheel drive output. Does that make sense? Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted March 8, 2021 Share Posted March 8, 2021 Transfer case has a fixed yoke on the front and back. I think I'm following what you're saying about the pinion angles... My original thought was to just have the front section of the two-piece drive shaft shortened to accommodate the transfer case. The rear section shouldn't change in theory assuming that from the carrier bearing/fixed slip yoke back nothing changes I guess what I'm saying is I'm not sure if the height of where the yoke is on the transfer case is the same as the two-wheel drive output. Does that make sense? It does make sense, but I do not think the change in pitch could be appreciable. The motor and transmission mounts are the same regardless. If the crankshaft axis is not the same as the frame rails you have at most 9-10" projection difference between the 2wd tailshaft and the output yoke of the transfer case??? If it were me (and I'm no driveline specialist) I would just shorten the front section, leaving the centre companion bearing and rear shaft alone. Link to comment Share on other sites More sharing options...
bp17oang Posted March 8, 2021 Author Share Posted March 8, 2021 It does make sense, but I do not think the change in pitch could be appreciable. The motor and transmission mounts are the same regardless. If the crankshaft axis is not the same as the frame rails you have at most 9-10" projection difference between the 2wd tailshaft and the output yoke of the transfer case??? If it were me (and I'm no driveline specialist) I would just shorten the front section, leaving the centre companion bearing and rear shaft alone. Yes I agree. Is the logic on the two piece driveshaft that the front section between the transfer case and bearing assembly be as "level" as possible? That way all of you downward angle to the axle pinion is taken up by the rear section? Thanks for your help! Link to comment Share on other sites More sharing options...
bp17oang Posted March 8, 2021 Author Share Posted March 8, 2021 It does make sense, but I do not think the change in pitch could be appreciable. The motor and transmission mounts are the same regardless. If the crankshaft axis is not the same as the frame rails you have at most 9-10" projection difference between the 2wd tailshaft and the output yoke of the transfer case??? If it were me (and I'm no driveline specialist) I would just shorten the front section, leaving the centre companion bearing and rear shaft alone. And also for clarity on why I'm a little confused about this part of it, while the mount is the same I had to use the crossmember out of the four-wheel drive because it is lower to accommodate the transfer case adapter. In addition to that the bracket on the 4-wheel drive where the carrier bearing mounts is 5" and the one on the two-wheel drive is 2" Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted March 8, 2021 Share Posted March 8, 2021 And also for clarity on why I'm a little confused about this part of it, while the mount is the same I had to use the crossmember out of the four-wheel drive because it is lower to accommodate the transfer case adapter. In addition to that the bracket on the 4-wheel drive where the carrier bearing mounts is 5" and the one on the two-wheel drive is 2" The drivers side drop driveshaft will hit the crossmember if it isn't low enough. Many of the later 4wd applications have some crazy asymmetrical crewmembers I'm not sure what exactly you're saying about the carrier bearing adapter being 2 or 5"? 2 or 5" drop? In a 350, the rear 10.25" axle would get 4" lift blocks for a 4wd application. I'm not certain what went on with a C&C truck in that regard. Link to comment Share on other sites More sharing options...
bp17oang Posted March 9, 2021 Author Share Posted March 9, 2021 The drivers side drop driveshaft will hit the crossmember if it isn't low enough. Many of the later 4wd applications have some crazy asymmetrical crewmembers I'm not sure what exactly you're saying about the carrier bearing adapter being 2 or 5"? 2 or 5" drop? In a 350, the rear 10.25" axle would get 4" lift blocks for a 4wd application. I'm not certain what went on with a C&C truck in that regard. What I am saying is the bracket that is attached the crossmember at the back of the cab, where the carrier bearing bolts to, on the 2wd that bracket is approximately 2" and the same piece on the 4wd is 5" Regardless, I think that issue is also water under the bridge. I did some rough measuring and with the addition of the transfer case on the 2wd chassis, it won't be feasible to retain the two piece system because the length of the front section would have to be cut to less than a foot long. Again this is rough measuring, but it looks like I will be looking for or having a one-piece driveshaft built that will be (again this is approximate) 62" long. I would have thought that there were trucks built with one piece rear driveshafts for the application I am putting together (136" wheelbase trucks with 460, T19/19, BW 1345, 4x4). I can't imagine they put two piece rear driveshafts with one foot (or less) front sections... but maybe I am wrong. Rough measurements show you are pretty darn close on the length you suggested on the front, not that I doubted you Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted March 9, 2021 Share Posted March 9, 2021 What I am saying is the bracket that is attached the crossmember at the back of the cab, where the carrier bearing bolts to, on the 2wd that bracket is approximately 2" and the same piece on the 4wd is 5" Regardless, I think that issue is also water under the bridge. I did some rough measuring and with the addition of the transfer case on the 2wd chassis, it won't be feasible to retain the two piece system because the length of the front section would have to be cut to less than a foot long. Again this is rough measuring, but it looks like I will be looking for or having a one-piece driveshaft built that will be (again this is approximate) 62" long. I would have thought that there were trucks built with one piece rear driveshafts for the application I am putting together (136" wheelbase trucks with 460, T19/19, BW 1345, 4x4). I can't imagine they put two piece rear driveshafts with one foot (or less) front sections... but maybe I am wrong. Rough measurements show you are pretty darn close on the length you suggested on the front, not that I doubted you There's plenty of room to doubt me. I'm just looking across the application data Spicer/Dana have available. Now I will look for a telescoping driveshaft for a 4x4 136" wb. Im going to assume that D70 takes a pretty beefy universal, and no one wants to go changing pinion yokes on that! Link to comment Share on other sites More sharing options...
bp17oang Posted March 9, 2021 Author Share Posted March 9, 2021 There's plenty of room to doubt me. I'm just looking across the application data Spicer/Dana have available. Now I will look for a telescoping driveshaft for a 4x4 136" wb. Im going to assume that D70 takes a pretty beefy universal, and no one wants to go changing pinion yokes on that! Yes, I am not terribly interested in changing that out... But it is what I have to work with. Link to comment Share on other sites More sharing options...
bp17oang Posted March 9, 2021 Author Share Posted March 9, 2021 There's plenty of room to doubt me. I'm just looking across the application data Spicer/Dana have available. Now I will look for a telescoping driveshaft for a 4x4 136" wb. Im going to assume that D70 takes a pretty beefy universal, and no one wants to go changing pinion yokes on that! I believe the Dana takes the same universal as my Sterling full floater did. But believing isn't knowing Link to comment Share on other sites More sharing options...
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