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Spydrdrvr 05-28-2013 07:02 AM

Which Transfer Case to use in Swap???
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I am working on my build right now. I am building a CJ7 with an LQ4 6.0 engine with a 4L65E tranny. I am using a YJ frame and Tub with CJ7 fenders and a Toyota 8" rear axle and an IFS with 4.56 gears. I will be running 35" tires. My problem is deciding which transfer case to run. I currently have a Dana 20 out of a '78 CJ7 and an NP205 out of a '78 Chevy. I also have the SM465 transmission that the NP205 is mounted to as well. I don't want to use the SM465 because I am going to be doing a lot of highway driving to and from the location I will be taking the Jeep. The Jeep is not my DD, but I do intend on using it for other things than wheeling.

Now, both transfer cases are gear driven and cast iron so they are solid in that aspect. The gear ratio in the 20 is 2.03:1 and in the NP205 it is 1.96:1. So in that aspect they are both pretty close and need upgrading. I also want to add the twin stick shifter and I can do that to either. The difference is the weight and length. The NP205 is about 86 pounds heavier than the 20 and about 2" longer. I don't know if the adapters that I will have to get to connect them to the tranny are going to make my driveline longer with one vs. the other. Since this is such a short wheelbase that will make a huge difference in my driveshaft angles since I will have to use a suspension lift to fit the 35's and a 1" body lift to fit the engine.

I also know I will have to add the crossmember for the NP205 for support and probably a frame support. It also looks like the NP205 will hang down lower than the 20 so that is a minor concern.

I am looking for some input and/or suggestions on which transfer case I should use, or if I should just get another transfer case to use with my set-up and get rid of the two transfer cases I have now. The engine and tranny I got came out of a 2005 GMC Yukon Denali that was AWD.

Any advice would be greatly appreciated as I am looking to order my adapters and mounts this week.

jp360cj 05-29-2013 08:12 AM

I assume you need a psd case?

if so, check into going with a d300. You already mentioned upgrading the low range. The 300 has 2.62 with as low as 4:1 available. Its also a very common swap to those transmissions so I believe the adapters will be considerably cheaper.

Redmanchew 05-29-2013 12:42 PM

X2 as long as you are staying passenger side...

Spydrdrvr 06-01-2013 09:32 AM

Thanks for the input from both of you! That actually sounds like a better idea. I guess I will look at selling the NP205 and the 20 now.

brownbagg 06-03-2013 06:23 AM

What does the sm465 have tp do with highway speed, they all have a final drive of 1:1. The 465 just has a better first gear.

jp360cj 06-03-2013 07:59 AM


Originally Posted by brownbagg (Post 15512981)
What does the sm465 have tp do with highway speed, they all have a final drive of 1:1. The 465 just has a better first gear.

Not sure what you mean by "they", but the 4l65e the op is swapping in has an overdrive 4th gear, around 0.7:1 iirc

Spydrdrvr 06-17-2013 05:58 AM

I have acquired a Dana 300 and I am now selling the NP205 and the Dana 20. Nothing like getting stuff and changing your mind. Oh well, that's what you have to do when building your Jeep to the best standards for your own preference. Thanks again for the great input, now I can move forward with my build!

ltrail 06-17-2013 11:21 PM

I thought toy ifs was DSD? I knew a customer of our old shop had hp44 ford front when he went SAS and full width. Either way, I measured for giggles and my sm465/203/205 is only a couple inches (2-4" depending) than running my 700r/205. That said I went for the doubler(variable in distance being my adapters) and keeping d60/70 factory gears at 4.11 for decent highway speeds. I have a fresh tbi350 to pull it along and mine will be mostly trail rig but like to drive to/from trails and the options of 1-2-4:1. I realize the freeways won't make my SBC happy at 2800rpm@70mph but for the availability of options and the fact that It's not gonna kill me to get a little more WB, its all worth it.

Not saying it's for you necessarily, just that i too have a 700r/241 i was gonna use but then thought about space vs ease of trail repair and the options of gear selection and settled in the manual with the doubler. It fits my style, maybe it would for you, maybe not. I wheel with a rubi and sometimes 4:1 is a bit much and 4hi isn't enough on 37's. In my case the lomax 205/teralow 4:1/d300 4:1 all were pricy for a single gear case. The doubler was the best option for all things considered. A big kicker for me being that the auto needs fluid pressure to operate, the manual does not. Not that i will bust the 465 but have lost a line on a 700r and had to pray nobody helped themselves while we went to town to grab parts. With the 465 it could have been babied back to the truck and a buddy trailer it home.

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