My 69 fj40 project - is this going to work? (1 Viewer)

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Joined
Aug 12, 2017
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Location
Annapolis,MD
So I am in waaaaay over my head. I have a project fj40 which I have completely torn down and now trying to put her back together....

new diamond full float axles 9.5” centered rear with arb air lockers

Chevy 383 fuel injected engine

nv4500 - used bell housing from advance adapters

np241 (was in the original when I bought it)

So I’ve got the wheels back on and trying to work out engine location.... is this going to work? Transfer case seems high for rear and short- 9” right now.....

Any help on positioning/config is greatly appreciated. I’ve learned a lot since starting this project but have lotta stuff to learn. Here are a few photos ... thanks in advance! Brandon
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IMO no it’s not gonna work. you have no room for a rear drive shaft and the front one will be a 4 footer. The drive shafts should be somewhat the same length within reason and then there’s the shaft angles. Wow you got in deep IMO.
 
How about a slip yoke eliminator for the rear of the NP 241? Claims to get you 5 more inches of drive shaft.


Otherwise find a shorter transfer case, like maybe a Dana 300 out of a 1981-1986 CJ? I don't think they are anywhere near that long.
 
How about a slip yoke eliminator for the rear of the NP 241? Claims to get you 5 more inches of drive shaft.


Otherwise find a shorter transfer case, like maybe a Dana 300 out of a 1981-1986 CJ? I don't think they are anywhere near that long.
Thanks! The sye would definitely give me some more space. Maybe a different transfer case would be better?
 
I am no pro, but also think you have alignment issues. As mentioned the overall assembly looks very long. I have a 5.3 vortec mated to and advance adapter bell, mated to an np4500, that is the connected to another advance adapter that allows the stock land cruiser transfer case to be used. I know there are stronger transfer cases, but this one fits. Ref pic for set up:

706A99C5-0046-43D4-9689-16031B66CBA0.jpeg
Note how much shorter everything is.

Also your alignment looks like the transfer case is closer to the passenger frame rail. I think it should be slightly closer to the driver side for front drive shaft clearance. Ref the advance adapters guide on fitting and mounting a new drivetrain in your 40. Your set up is different, but I think there are some fundamentals there that can help.


If you dig around in the tech pages, there are some gems....

Good luck!

- edit - just noticed you are in MD - I am just down the road if you want to check out my set up.....
 
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It honestly may work ok. My rear shaft is about the same length, but you probably have a bit more offset than me. Can you change the output on the 241, or change the t-case? Most guys don't run the chevy tcases.

Have you checked the alignment of the engine to the frame? That output should be much more centered.

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It honestly may work ok. My rear shaft is about the same length, but you probably have a bit more offset than me. Can you change the output on the 241, or change the t-case? Most guys don't run the chevy tcases.

Have you checked the alignment of the engine to the frame? That output should be much more centered.

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Thanks for the reply - the engine alignment is not correct right now - I've got the engine brackets just clamped in place while I try to sort out the positioning.
I am no pro, but also think you have alignment issues. As mentioned the overall assembly looks very long. I have a 5.3 vortec mated to and advance adapter bell, mated to an np4500, that is the connected to another advance adapter that allows the stock land cruiser transfer case to be used. I know there are stronger transfer cases, but this one fits. Ref pic for set up:

View attachment 2642617Note how much shorter everything is.

Also your alignment looks like the transfer case is closer to the passenger frame rail. I think it should be slightly closer to the driver side for front drive shaft clearance. Ref the advance adapters guide on fitting and mounting a new drivetrain in your 40. Your set up is different, but I think there are some fundamentals there that can help.


If you dig around in the tech pages, there are some gems....

Good luck!

- edit - just noticed you are in MD - I am just down the road if you want to check out my set up.....
thanks again! I’m in Arnold, MD so really close! Your transfer case is much shorter! Any chance you know a mobile welder? Also did you make your own mount for the transmission / transfer case?
 
Thanks for the reply - the engine alignment is not correct right now - I've got the engine brackets just clamped in place while I try to sort out the positioning.

thanks again! I’m in Arnold, MD so really close! Your transfer case is much shorter! Any chance you know a mobile welder? Also did you make your own mount for the transmission / transfer case?
Cool - nice to know there is another 40 fan close! I have not used a mobile welder in the area. There is a metal fab shop down the road from me that looks like they know their stuff and they have a mobile service. I have been doing my own welding... does not look great but have been having fun learning new skills and improving. Ref pic for address and number:

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I did make my own skid plate/tranny mount. In retrospect I might have done a couple things different, but overall I am happy. It has recessed mounting bolts and covers a lot without hanging down too far. Kinda wish I had taken more time to clean up the welds on the edges, but I have done worse things...😁. Here are a couple shots of the effort.

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Keep in mind @Krenie and @DangerNoodle 's examples are with offset rear output transfer cases. You are going to have to deal with the length of the driveline along with the height of the center rear output t/case in relation to your rearend. Looking at their pics, your output will be where the upper cone is, which is about 6 higher.. The big issue you need to keep in mind is how much bind will the driveshaft be in when the suspension is at full droop. I'd recommend using a Dana 300 or something like that. The only disadvantage of the 300 is the NP241 has a lower low range. IIR, the 241 is somewhere around 2.72:1 and the dana 300 is approx 2.62:1. The 300 can be twin sticked which offers 1 stick for the rear end and the other stick is for the frt end, this allows for frt engagement only(frt dig). The only draw back to this is you could inadvertently shift 1 stick in low and 1 in high, which will break the t/case. You can add detents to the shifter rail to help eliminate this issue, though it's not perfect. You would have to do some research, but IIR, some NV4500's have the same output spline as the input of the dana 300. You might only have to get a 3/4"thick clocking ring to adapt the 2. The Dana 300 also came with short and long outputs versions and each do not have slip yokes on the rear. The 241 is popular with some jeep owners because it is stronger than the NP231 installed in them, so there is a market for your 241. The 300 is gear driven and is pretty strong and can be upgraded in strength if it's needed, plus they have low range kits for them. Several yrs ago I did a similar upgrade to a center rear output t/case using a different trans and dana case and I'm very happy with it.
 
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Keep in mind @Krenie and @DangerNoodle 's examples are with offset rear output transfer cases. You are going to have to deal with the length of the driveline along with the height of the center rear output t/case in relation to your rearend. Looking at their pics, your output will be where the upper cone is, which is about 6 higher.. The big issue you need to keep in mind is how much bind will the driveshaft be in when the suspension is at full droop. I'd recommend using a Dana 300 or something like that. The only disadvantage of the 300 is the NP241 has a lower low range. IIR, the 241 is somewhere around 2.72:1 and the dana 300 is approx 2.62:1. The 300 can be twin sticked which offers 1 stick for the rear end and the other stick is for the frt end, this allows for frt engagement only(frt dig). The only draw back to this is you could inadvertently shift 1 stick in low and 1 in high, which will break the t/case. You can add detents to the shifter rail to help eliminate this issue, though it's not perfect. You would have to do some research, but IIR, some NV4500's have the same output spline as the input of the dana 300. You might only have to get a 3/4"thick clocking ring to adapt the 2. The Dana 300 also came with short and long outputs versions and each do not have slip yokes on the rear. The 241 is popular with some jeep owners because it is stronger than the NP231 installed in them, so there is a market for your 241. The 300 is gear driven and is pretty strong and can be upgraded in strength if it's needed, plus they have low range kits for them. Several yrs ago I did a similar upgrade to a center rear output t/case using a different trans and dana case and I'm very happy with it.
Thanks to everyone for the suggestions and feedback - much appreciated! I think I am going to start reviewing the dana 300 approach as an alternative, I think that would be a bit easier on my wallet compared to the atlas, plus the wait time on the atlas is 15 weeks or so. also need to think about whether the twin stick approach...not sure I would get much use out of that capability.
 
Flip the rear leafs for 3" more wheelbase
I did this and lowered the rear tranny crossmember about a inch. I wanted to run a single ujoint on each end of the d/s, and not have it bind at full droop. The pinion was raised up some too. My driveline is a lot shorter than the OP's too.
 

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