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I currently have a NP435 behind the 4BT in my wrangler (build is on here). Since the synchronizers for 2nd gear need replaced, I'm thinking of just going to a 5 speed. I have a line on two different options right now. GM 1992 model NV4500 with a 241C transfer case or a 1995 Jeep AX-15 with a 231J transfer case. I'm aware the NV4500 is plenty strong, but what say you about the AX-15 behind the 4bt??? Prices are really close, so length is going to be a big factor. Both sellers are getting me dimensions now. It appears I can do a slip yoke eliminator on both transfer cases, so that will help some. AX-15 appears to require an adapter to my Ford Bellhousing, which Novak sells, and a clutch disc change for the larger shaft (1-1/8 instead of 1-1/16). Mating a GM NV4500 to my Ford bellhousing?? The AX15 "seems" like an easier choice and perhaps better suited gear-wise. Your thoughts, please???

On to my alternator woes. I have a GM style alternator on the 4bt, listed as application for a 1996 GM K3500 with a 5.7 liter engine. This alternator requires the traditional heavy wire to the alternator, and a 12 volt connection to the exciter circuit labeled "L". I have the 12 volt "L" wire run from the switch that supplies power to the fuel shutoff solenoid and the gauges. My battery seems to drain down when parked. Am I losing juice through the diodes in the alternator by having the solenoid on the same circuit? The motor will not start with the switch off, so the solenoid is not getting enough backfeed to engage it...Thoughts on that? Also, I just put the second new alternator on since getting this running a couple of months ago. I wonder if the exciter circuit is all that failed, but havent had it checked yet. If there is a true ONE WIRE alternator with that style frame, I'd like to know about it. All the true one-wires I have seen have the two lugs 180 degrees apart. This frame has the two mounting lugs about 110 degrees or so, and that is all that will fir my mount.
 

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On your transmission questions, the AX-15 is not quite as strong as a NV4500. The AX-15 is rated for 300 lb ft torque input and is probably safe for a bit more. So much would depend on how you treat it. Adapters are available using a Ford bellhousing so you would keep the parts you have. The NV4500 has a torque rating of 450 lb ft so it's 50% stronger. It is essentially a NP435 with an OD gear added. The '92 NV4500 is sort of an odd duck. It has a lower 1st gear that is not synchronized and a odd bolt pattern on the housing. To adapt it to a 4bt you would need the GM bellhousing, adapter plate, and flywheel which would make it essentially a bolt on. Those adapter plates are pretty common but the flywheel is a bit scarce. They can be found. Those adapter plates place the transmission in a tilted position so you'd need to keep that in mind. If your NV4500 were a '95 and up GM part you could adapt it using a Dodge Cummins adapter and flywheel and change the input shaft to a Dodge. Not an alternator specialist but sounds like you have something drawing current when the ignition is off. Need to disconnect the wire and check with a test meter to see if there is a current draw. If there is no current flow from the main battery wire to the alternator then you have some other source at fault. Wouldn't see how the excite wire could draw if it's controlled by the ignition switch. Possibly a bad diode in the alternator allowing current to back feed from the battery.
 

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In regards to Charlie’s comment on checking the draw on your battery. Use a meter to to check the draw and not a test light. I’ve got enough draw to light a test light but it’s very low on the meter. And it is from my GM alternator. Nature of the beast
 

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I currently have a NP435 behind the 4BT in my wrangler (build is on here). Since the synchronizers for 2nd gear need replaced, I'm thinking of just going to a 5 speed. I have a line on two different options right now. GM 1992 model NV4500 with a 241C transfer case or a 1995 Jeep AX-15 with a 231J transfer case. I'm aware the NV4500 is plenty strong, but what say you about the AX-15 behind the 4bt??? Prices are really close, so length is going to be a big factor. Both sellers are getting me dimensions now. It appears I can do a slip yoke eliminator on both transfer cases, so that will help some. AX-15 appears to require an adapter to my Ford Bellhousing, which Novak sells, and a clutch disc change for the larger shaft (1-1/8 instead of 1-1/16). Mating a GM NV4500 to my Ford bellhousing?? The AX15 "seems" like an easier choice and perhaps better suited gear-wise. Your thoughts, please???

On to my alternator woes. I have a GM style alternator on the 4bt, listed as application for a 1996 GM K3500 with a 5.7 liter engine. This alternator requires the traditional heavy wire to the alternator, and a 12 volt connection to the exciter circuit labeled "L". I have the 12 volt "L" wire run from the switch that supplies power to the fuel shutoff solenoid and the gauges. My battery seems to drain down when parked. Am I losing juice through the diodes in the alternator by having the solenoid on the same circuit? The motor will not start with the switch off, so the solenoid is not getting enough backfeed to engage it...Thoughts on that? Also, I just put the second new alternator on since getting this running a couple of months ago. I wonder if the exciter circuit is all that failed, but havent had it checked yet. If there is a true ONE WIRE alternator with that style frame, I'd like to know about it. All the true one-wires I have seen have the two lugs 180 degrees apart. This frame has the two mounting lugs about 110 degrees or so, and that is all that will fir my mount.
I have a perfectly nice working G360 behind my 5.9 with a 205 bolted to it I might be looking to find a new home for. I am wanting to replace it with a upgraded NV4500 with the 1.375 input shaft and may even choose the cryo treated parts. I found a place that says they are working on a new version for swapping G360's for NV4500 boxes with surface ground not hobbed gears with improved main and counter shafts. I don't want to rid myself of the 205 but intend to replace the main shaft there for an improved version since they are rated for like 5.5k lb ft of torque. The 271 chain drive case is rated for 7k but all the chain units are for the wrong side axle input. I would do that if I could find a high pinion unit that would work in my 91 W350. I would even more so like to leave the front as is and make it a high pinion because high pinion units are just better for front axles, they push the pinion back into the case instead of pulling against the small bearing. It just make more sense. I don't even need a working 4500 I would take a unit that needed worked on as long as it was with the bell housing. I would let my bell housing go with my trans. I overhauled it a while back after I took out the bearings and basically smoked it completely by letting the oil level get too low. It was shortly after I got the truck and I didn't know the rear seal was bad letting oil collect in the Tcase adapter. It got a new lower shaft, input, front replaceable gears, synchros, bearings and forks, main shaft, so for the most part all I used was the case and upper rear gears, put in new slider on 4-5 not long after I did that as I thought I could get away with cleaning up the small damaged spot on that slider, not, it took out the fork a second time a few years later, so I did it again with new parts. Been working now flawlessly for about 17 years. I read a working G360 in great shape goes for around 1300 by itself, the rest of the pieces obviously run that price higher. I replaced the clutch and plate not long ago and had the wheel resurfaced. My plan was to install a dual disc when I switch. Of course once I take it out, I will check the shafts to see that there is not excessive play in the upper bearings and probably even the lowers, if they need re adjusted I will do that before I let it go unless new owner wants to have it gone through by a trans shop and have a warranty if offered. I can't offer a warranty even after I check it out as it is still a used unit that has been worked pulling loads, I just know it still works as I drove it recently and will drive it more before it leaves.
 

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I have an ax15 in my early bronco with a hx30w. About 1500 miles on it so far and no issues. They are rated for the aforementioned torque, but with a much heavier setup, so if your rig is lighter and you don’t plan on dropping the clutch or heavy tows you should be fine.
 

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The longevity of a transmission can depend on how you treat it. Drive normally with a degree of sanity and it will probably cause no problems. Get cocky, show off, and treat it badly and it will likely die a quick death. That low end torque which a Cummins is famous for just loves to have guys try burnouts and wonder why the transmission is making strange noises and won't shift properly.
 
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