datzenmike Posted May 27 Report Share Posted May 27 A U joint just won't do. The 4x4 720 uses a slip joint in the rear driveshaft to allow for the rear axle to move forward and back under high torque loads and suspension articulation. 2wd had the U joint but the front of the driveshaft was splined into the rear of the transmission to allow axle movement. Quote Link to comment
Metalguy Posted May 30 Author Report Share Posted May 30 Both of my driveshafts are splined for articulation of suspension. I was asking if the extra joint that the stock driveshaft will still have to be there, the one that goes through the carrier bearing stock. I'm guessing it is going to be uneccessary. Currently, I have a two piece front driveshaft with splines, and just the rear piece of the rear driveshaft, ending in splines. The front needs a yoke that bolts to the transfer case, with u -joint, and the rear needs the mating splined piece, and a yoke for u-joint on the other end. I believe I can remove the yoke from the rear of the transmission and slip the yoke into it that attaches to the very short shaft that drives the transfer case. The short shaft has two u-joints in it. Quote Link to comment
Metalguy Posted June 8 Author Report Share Posted June 8 I made some progress on this truck, and found out a few things. The front brakes are indeed Datsun brakes. The backing plate was adapted to this Dana 30 front axle. I put on new shoes, and wheel cylinders. I also believe it has a stock 4 speed transmission. The speedo cable is hooked up to it. I think some other divorced transfer case was originally used, but I'll be using the Datsun one I bought. So I ask you gurus for help! When using this transfer case, should the speedo cable be moved to the transfer case? Do I need to plug the one on the transmission? If so, how? Also, should I use a regular cab 4x4 rear drive shaft? And one more: can the coupler that is bolted onto the rear of the transmission be removed, and the splinted shaft to feed the transfer case just be slid inside, and used? I'll post pics of the stub shaft for the trans. 2 Quote Link to comment
Metalguy Posted June 8 Author Report Share Posted June 8 (edited) If I remove this nut, and flange, can I use that stub shaft by sliding it onto the rear of the transmission? Edited June 8 by Metalguy Left out text 1 Quote Link to comment
datzenmike Posted June 8 Report Share Posted June 8 I would leave the speedometer cable where it is. It will only read wrong when in low range, so who really cares in the bush? Yes this will fit and seal to your 4 speed but polish up the seal surface and for best results replace the rear transmission seal. 2 Quote Link to comment
]2eDeYe Posted June 8 Report Share Posted June 8 That is most likely a Dana 20 transfer case that you pulled out of there. Just FYI Quote Link to comment
Metalguy Posted June 8 Author Report Share Posted June 8 Could very well have been a Dana20 transfer case. It was MIA when I got the truck, along with the front portion of the rear driveshaft. I will polish that up before installing, thanks! I will probably replace that seal, too. It is already wet back there so it is most likely not in the best of shape. Is it a pretty straightforward job to replace? No special tools required? Again, thank you both for the help! I'm looking forward to getting this thing moving under it's own power. Quote Link to comment
datzenmike Posted June 8 Report Share Posted June 8 You can just pry the old seal out being careful not to score the inner part of the transmission. Set the new seal in place and cover with a block of wood. Make sure the seal is not cocked sideways and hammer it in flush. Use a suitable size pipe or a socket to finish seating it all the way in. Either grease the seal lips before installing or grease the driveshaft before sliding it in. This will prevent it starting up dry. 1 Quote Link to comment
Metalguy Posted Tuesday at 08:50 PM Author Report Share Posted Tuesday at 08:50 PM The seal arrived today. I have yet another newbie question.... On the differential (stock rear), can the stock flange be changed to a newer style? It would be nice to use a stock, or nearly stock rear driveshaft that has the larger flanges that match the t 100 transfer case. Otherwise, I'll have to use the small one that is on the diff, and the large one on the other half of the rear driveshaft, and I believe even the newer ones had larger splines in the front part of the rear driveshaft. Any advice? I'd like the simplest solution, and if I can swap the flange, I think it will simplify things. I hope I'm making sense........ Quote Link to comment
Stoffregen Motorsports Posted Tuesday at 09:03 PM Report Share Posted Tuesday at 09:03 PM Wouldn't it be best to cut the threaded portion off the tailshaft to get more spline engagement? Quote Link to comment
Stoffregen Motorsports Posted Tuesday at 09:05 PM Report Share Posted Tuesday at 09:05 PM 13 minutes ago, Metalguy said: The seal arrived today. I have yet another newbie question.... On the differential (stock rear), can the stock flange be changed to a newer style? It would be nice to use a stock, or nearly stock rear driveshaft that has the larger flanges that match the t 100 transfer case. Otherwise, I'll have to use the small one that is on the diff, and the large one on the other half of the rear driveshaft, and I believe even the newer ones had larger splines in the front part of the rear driveshaft. Any advice? I'd like the simplest solution, and if I can swap the flange, I think it will simplify things. I hope I'm making sense........ I'm not sure there were other flanges that bolt on. Someone here will surely know. In any case, your local driveline shop can make any shaft with any flange or slip yoke. There is an online store that I've used before for driveshaft parts. I think it's called driveshaftpart.com Yep - https://www.driveshaftparts.com/ 1 Quote Link to comment
Metalguy Posted Tuesday at 10:34 PM Author Report Share Posted Tuesday at 10:34 PM Thanks for that source. I may end up just going that route for both shafts. My front shaft is SAE on both ends, and with the t 100 transfer case, I'll need a metric end and yoke for that. Anyway, thanks again for the info! 1 Quote Link to comment
Metalguy Posted Friday at 07:13 AM Author Report Share Posted Friday at 07:13 AM Well, the driveshaft for the transfer case doesn't fit the tail of the transmission, as they are different sizes. I removed the tailshaft off the transmission , but the splines, and shaft aren't the same. I guess that was changed on the newer models. Quote Link to comment
]2eDeYe Posted Friday at 12:50 PM Report Share Posted Friday at 12:50 PM The Dana stuff is essentially Jeep. The u-joints are 1310's. The Datsun/Nissan stuff is, well I am not sure exactly, you can get conversion flanges for the 1310 to the Nissan stuff. Not sure if this is the right one, but as an example. https://www.drivetrainamerica.com/3102-21-1310-series-nissan-flange-yoke/ 1 Quote Link to comment
datzenmike Posted Friday at 01:15 PM Report Share Posted Friday at 01:15 PM These are the later primary drive shafts reflecting the two different transmission lengths. The earlier drive shafts were smaller diameter and smaller U joints (and I don't think there were two lengths) and of course the transfer case had different size flanges to match. I had an earlier T-100 with smaller flanges and swapped the later larger size flanges and drive shafts on. 2 Quote Link to comment
Metalguy Posted Friday at 03:03 PM Author Report Share Posted Friday at 03:03 PM The conversion flange is exactly what I need for the front shaft. And now I'm thinking I may get a parts truck to get the other things I need so it will all fit together ( Later trans, and rear driveshaft, third member) Does anyone know if the third member from an early 80's will fit into a 1971 rear axle assy? Or where I could find an early primary drive shaft? Sure would make things easier. Quote Link to comment
Stoffregen Motorsports Posted Friday at 03:26 PM Report Share Posted Friday at 03:26 PM Seriously, any driveline shop can build the shaft, without having to change out your diff. Just bring them the flange from the diff and the t-case, trans, whatever, and a length measurement and they can find the right flanges, joints, etc. Use that website for the diagrams and figure out which flanges you have. That may help too. The diagrams on that site are really pretty good. 2 Quote Link to comment
datzenmike Posted Friday at 06:36 PM Report Share Posted Friday at 06:36 PM Forgot. The bottom one is for the smaller diameter, you* can clearly see the yokes and U joints are smaller... * obviously I can't! 1 Quote Link to comment
Metalguy Posted Friday at 06:41 PM Author Report Share Posted Friday at 06:41 PM Yep, I need one of those.I have the larger flanged T100, but trans has the smaller opening. With one of those, I could source a large flange end to adapt it to the transfer case end, and the smaller nose would fit my transmission. One I had that, I could fab mounts to mount the transfer case, then get a length measurement for the front of the rear driveshaft I am missing. Quote Link to comment
datzenmike Posted Friday at 06:46 PM Report Share Posted Friday at 06:46 PM The splines are all the same. I've never seen a Datsun/Nissan transmission that won't accept a Datsun/Nissan driveshaft. 1 Quote Link to comment
Metalguy Posted Friday at 09:51 PM Author Report Share Posted Friday at 09:51 PM The splines are certainly different. Quote Link to comment
Stoffregen Motorsports Posted Friday at 10:02 PM Report Share Posted Friday at 10:02 PM 3 hours ago, datzenmike said: The splines are all the same. I've never seen a Datsun/Nissan transmission that won't accept a Datsun/Nissan driveshaft. 289zx turbo had larger splined shaft. Quote Link to comment
Stoffregen Motorsports Posted Friday at 10:03 PM Report Share Posted Friday at 10:03 PM 3 hours ago, Metalguy said: Yep, I need one of those.I have the larger flanged T100, but trans has the smaller opening. With one of those, I could source a large flange end to adapt it to the transfer case end, and the smaller nose would fit my transmission. One I had that, I could fab mounts to mount the transfer case, then get a length measurement for the front of the rear driveshaft I am missing. If the inner register on the flange is the same diameter between the two, you can drill new holes in the existing t-case flange. I do this a lot with Toyota stuff. 2 Quote Link to comment
datzenmike Posted Friday at 11:17 PM Report Share Posted Friday at 11:17 PM 1 hour ago, Metalguy said: The splines are certainly different. 1 hour ago, Stoffregen Motorsports said: 289zx turbo had larger splined shaft. I didn't expect anyone to know this. I had a turbo automatic and yes it was larger, makes sense that the T5 was also. Neither of these are viable candidates for use other than on the 280zx. In other words, you are unlikely to come across this. 2 Quote Link to comment
Stoffregen Motorsports Posted yesterday at 12:14 AM Report Share Posted yesterday at 12:14 AM 55 minutes ago, datzenmike said: I didn't expect anyone to know this. I had a turbo automatic and yes it was larger, makes sense that the T5 was also. Neither of these are viable candidates for use other than on the 280zx. In other words, you are unlikely to come across this. That's a bingo! And thinking about the flange - if it's square, not round, you may not be able to drill another set of holes. 1 Quote Link to comment
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