Littlebeefy Posted July 9, 2022 Share Posted July 9, 2022 Chad - Tell us more about what t-case you used? Is that the NP205? I've not played with one of those, but what made it difficult to use the linkage with it? Hi Gary. Ya, I've got an NP205 like what would have been found in a 78/79. It is way easier linking up the aluminum t-cases. The NP205/ZF5 combo has a lot of complications. It has twin shift rails. Technically, it fits the tailhousing bolt pattern, but the housing has to be clearanced to allow one of the shift rails. Plus, there isn't that length of input housing on the NP205 like there is on the 208 or the BW units, so the shift rails are much closer to the transmission case. If you set all the aluminum units on a table next to the NP205, it's shape would stick out like a sore thumb; it is dramatically different compared to the minor differences on the aluminum units. Additionally, that iron transfer case weighs about as much as the whole ZF5 (I've lifted them both so I know first hand). So you have to find a way to mount it to a support off the frame with a bushing or your ZF5 will definitely crack. Frankly, I didn't have the transfer case shift linkage for either the NP205 or the ZF5, so it seemed like hunting down original parts without knowing how they would fit (or if I could make them fit) would be a boondoggle. There are two bosses accessible on the ZF5 that could probably be used to engineer a linkage solution. I haven't tried using the part from the NP205 that links the shift rails together so I'm not even sure if that would work with the ZF5 even after it was clearanced. Again, since the Bullnoses have the transfer case shifter in the transmission tunnel cover and the later 5 speed trucks don't, once you put the later transmission tunnel cover on the Bullnose, there is no longer a hole to allow access for a transfer case shifter, so you have to choose where to cut one no matter which direction you go with the linkage. I decided to go with a twin stick cable actuated shifter from JB Fabrication. That way I could take advantage of the dual shift rods. That thing is massive though so I still haven't cut the transmission tunnel cover to mount it. I'm going to have to weld on some framing for the shifter to bolt to. Like I said earlier, I think the t-case shift linkage is the most complicated part of the ZF5 swap and it's even more complicated with an NP205. I created these issues myself by swapping out everything so I'm not complaining. Engineering the solution is part of the fun. I included a couple pics that shows the trailing edge of the tailhousing where you can see the clearancing I did for the shift rail and another pic that shows the transmission and transfer case bolted together. If anybody is dying for pictures, let me know what you want to see and I will snap some while I am under there this weekend installing a ground strap on my fuel tank. Link to comment Share on other sites More sharing options...
Rembrant Posted July 9, 2022 Share Posted July 9, 2022 I think it's very fortunate that I didn't have to find that funky shift boot and cut a hole in the side of my tunnel. I cut the hole in the side of the tunnel in my 1980 for the M5OD and the 1356. One, I didn't have the original case and controls, and two, I didn't mind zip-cutting the floor in this truck as it wasn't s how winner anyway lol! One downside to the location of that transfer case shifter being that far left...at least in the north, is that the screw holes filled up with salt from shoes/boots/floor and rusted to pieces...which made them extremely difficult to remove lol. Â Link to comment Share on other sites More sharing options...
Gary Lewis Posted July 9, 2022 Share Posted July 9, 2022 I think it's very fortunate that I didn't have to find that funky shift boot and cut a hole in the side of my tunnel. I cut the hole in the side of the tunnel in my 1980 for the M5OD and the 1356. One, I didn't have the original case and controls, and two, I didn't mind zip-cutting the floor in this truck as it wasn't s how winner anyway lol! One downside to the location of that transfer case shifter being that far left...at least in the north, is that the screw holes filled up with salt from shoes/boots/floor and rusted to pieces...which made them extremely difficult to remove lol. Chad - I had no idea the 205 required that kind of work. Wow! I'm glad I stayed with the Bullnose t-cases. From my reading though I understand that the twin-stick approach allows you to use 2WD Low range. And it also allows you to have front wheel drive only. Those are intriguing. And I'd forgotten that I did have to cut the tunnel cover, but since I had the Bullnose cover it was easy to figure out where to cut it. Cory - I hadn't thought about the snow melt and salt. We don't have enough snow any more to make that an issue, but I can see how it could be if you did it day after day in the winter. Anyway, your installation looks (looked?) good. Link to comment Share on other sites More sharing options...
Nothing Special Posted July 9, 2022 Share Posted July 9, 2022 Chad - I had no idea the 205 required that kind of work. Wow! I'm glad I stayed with the Bullnose t-cases. From my reading though I understand that the twin-stick approach allows you to use 2WD Low range. And it also allows you to have front wheel drive only. Those are intriguing. And I'd forgotten that I did have to cut the tunnel cover, but since I had the Bullnose cover it was easy to figure out where to cut it. Cory - I hadn't thought about the snow melt and salt. We don't have enough snow any more to make that an issue, but I can see how it could be if you did it day after day in the winter. Anyway, your installation looks (looked?) good. As you are looking for a ZF5, keep in mind that since the bellhousing is an integral part of the transmission you need to get one that will fit your big block. From least common to most common, they made them for small blocks (which won't work at all for you), big block gassers (which would be a direct bolt-on) and diesels. Diesels are probably the most common, and one MIGHT work on a big block. I know they are close and I've read that you can relatively easily modify one to work on the other. But I don't know if you can only put a diesel trans on a gas engine, or a big block trans on a diesel engine or if you can do it either way. And I don't know what you have to change. So sorry for not having the answers, but at least it might help you find the right questions. Link to comment Share on other sites More sharing options...
Gary Lewis Posted July 9, 2022 Share Posted July 9, 2022 As you are looking for a ZF5, keep in mind that since the bellhousing is an integral part of the transmission you need to get one that will fit your big block. From least common to most common, they made them for small blocks (which won't work at all for you), big block gassers (which would be a direct bolt-on) and diesels. Diesels are probably the most common, and one MIGHT work on a big block. I know they are close and I've read that you can relatively easily modify one to work on the other. But I don't know if you can only put a diesel trans on a gas engine, or a big block trans on a diesel engine or if you can do it either way. And I don't know what you have to change. So sorry for not having the answers, but at least it might help you find the right questions. Good point, Bob, and one we'd forgotten. But, there's a big difference in gear ratios between the diesel and gas ZF5's. The diesels have a close-ratio gearset and the gas trannys have a wide-ratio gearset. ZF5 - Close 1st: 4.14 2nd:2.37 3rd: 1.42 4th: 1.00 5th: 0.77 ZF5 - Wide 1st: 5.72 2nd:2.94 3rd: 1.61 4th: 1.00 5th: 0.76 Depending on your intended usage that may make a big difference. For me the low 1st gear of the wide-ratio gearset is the only way to go. But I will admit that there's a wide jump between 3rd and 4th so going to 3rd at much of a speed is questionable. On the other hand, when we were running the carb on this engine and climbing the passes around Ouray we found that we could go a lot of places in 3rd if we kept the R's up. Now, with EFI, that won't be necessary and I'll bet 3rd is going to be "the gear" when in low range. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted July 9, 2022 Share Posted July 9, 2022 As you are looking for a ZF5, keep in mind that since the bellhousing is an integral part of the transmission you need to get one that will fit your big block. From least common to most common, they made them for small blocks (which won't work at all for you), big block gassers (which would be a direct bolt-on) and diesels. Diesels are probably the most common, and one MIGHT work on a big block. I know they are close and I've read that you can relatively easily modify one to work on the other. But I don't know if you can only put a diesel trans on a gas engine, or a big block trans on a diesel engine or if you can do it either way. And I don't know what you have to change. So sorry for not having the answers, but at least it might help you find the right questions. Bob, only the top two bolt holes are the same IDI diesel- big block gas pattern. The locating dowels are bigger for diesel and the starter is far different. Ford used an adapter plate on the IH engines. I suspect they came with an SAE pattern. I have heard that some people have been able to weld up the gas pattern bellhousing and bore out new holes, but that would take some serious mill (no separate bellhousing on the Zf, so you'd have to fixture the whole trans) and an accurate pattern. I've never heard of someone going the other way. And like Gary said, the higher 1st and tighter ratios don't really suit a 460. I'm not sure what you could do about the starter. They are unique to diesels. For sure the diesel flywheel is not the same as a 460. Link to comment Share on other sites More sharing options...
Littlebeefy Posted July 9, 2022 Share Posted July 9, 2022 Bob, only the top two bolt holes are the same IDI diesel- big block gas pattern. The locating dowels are bigger for diesel and the starter is far different. Ford used an adapter plate on the IH engines. I suspect they came with an SAE pattern. I have heard that some people have been able to weld up the gas pattern bellhousing and bore out new holes, but that would take some serious mill (no separate bellhousing on the Zf, so you'd have to fixture the whole trans) and an accurate pattern. I've never heard of someone going the other way. And like Gary said, the higher 1st and tighter ratios don't really suit a 460. I'm not sure what you could do about the starter. They are unique to diesels. For sure the diesel flywheel is not the same as a 460. I've definitely heard about people trying to convert the diesel case to a gasser. It ends with a listing on Craigslist for diesel ZF5 with a cracked bellhousing. I'm not saying the successes aren't out there, but I don't see them as much as I do the failures... Back to the original poster's question. If you are unhappy with your lack of overdrive, why not just install a one of those units as an add on? I think I heard them called gear doublers? Seems like a significantly easier way to go if all your missing is a highway gear. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted July 9, 2022 Share Posted July 9, 2022 I've definitely heard about people trying to convert the diesel case to a gasser. It ends with a listing on Craigslist for diesel ZF5 with a cracked bellhousing. I'm not saying the successes aren't out there, but I don't see them as much as I do the failures... Back to the original poster's question. If you are unhappy with your lack of overdrive, why not just install a one of those units as an add on? I think I heard them called gear doublers? Seems like a significantly easier way to go if all your missing is a highway gear. Dave (fuzzface2) has a gear vendors overdrive under his flareside. Probably because the units that fit T-19's are $3,200??? https://www.gearvendors.com/4x4fmanual.html Link to comment Share on other sites More sharing options...
Littlebeefy Posted July 9, 2022 Share Posted July 9, 2022 Dave (fuzzface2) has a gear vendors overdrive under his flareside. Probably because the units that fit T-19's are $3,200??? https://www.gearvendors.com/4x4fmanual.html Ouch. I withdraw the question. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted July 9, 2022 Share Posted July 9, 2022 Ouch. I withdraw the question. I also think since these units go between the gearbox and the transfer case you need to think about additional support and new (or modified) driveshafts as well. Link to comment Share on other sites More sharing options...
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