NP241 vs NP205 which tcase to use in a sas

[Rick1217]

Hey, I have been searching and I am kinda stuck on which transfer case to use, just wanted some input on which one would be better or worse.
The truck is a 91 k1500 ext cab short box. It has a mild rebuilt 350, I will have two trans options, right now I have a strong working stock th400/np241 in it but I have a built 2wd th400 that could be used as either to convert it to 4x4 or use it with a divorced tcase. I have 38.5s, the truck is mainly offroad and it gets driven really hard, I will be running chevy d60/14ff. Now i have a few options here, I am looking for something that will be strong but cost effective aswell. Should I hunt down a np205 and Do a divorced set up or married set up? Should I just use NP241 pass drop? Should I do a doubler np203/205? What are some pros and cons from your point of veiw?
also does anyone know the overall length of a 205/203 doubler? vs a 241? Thanks

[trkklr77]

since you dont have the 205 run the 241, they are good cases with a lower gear than a 205 and are much stronger than a 231/208.

you are running an assload of lift so it would deffinatly be in the best interest to run a clocked down 205.

[Rick1217]

3" of that is body... and I dont have a tcase that will work for me at the moment, so all options are open, my 241 is a drivers drop i need a pass drop tcase, so either way ill need a new tcase... there will be a total of 8-12" of suspension lift with my new set up probably closer to about 9-10" Im leaning towards the sky kit so 6" brackets plus maybe 3-4" springs I have a stock set of rear 81 springs that I will try out and see what I need from there to get 38s to fit with no clearance problems.

[scottjkj1]

Ditto on the 241, its a lot stronger than some may give it credit. The 205 is stonger though and is gear driven so it does have its advantages. I run a 241 with a SYE and run 40 inch tires on my suburban and have never had a problem out of it.

[Rick1217]

Yeah thats kinda where I have been leaning towards... I know there are alot of people that havnt had problems... how long have you been running 40s? does anyone know if the 205 has a spot to even put a speedo? or is it differant on them? I have not really looked at one up close before...

[Rick1217]

Also one thing to keep in mind, I was researching and I found out the 2wd output shaft is the same one used on 4x4 models with np205s and My adapter might work from my np241/th400 so I can get a 205 to work without have to buy more parts and open the tranny up. So I can used the built tranny and just have to buy and bolt a np205 to it, I will for sure need new driveshafts but thats a given... After finding that out I might have to lean more towards the np205... it will be easier to swap it over so thats the main thing plus its alot stronger.
The gear ratio is not a big deal to me, I wouldnt mind abit lower but the 2to1 ratio is okay..... Im probably going with 4.88s in the new diffs so i will loose a little bit crawl ratio, but I think I have 24.9to1 with my set up now and Ill have about 24.2 after so no big deal, I like mud more than the rocks so i should be okay, although there was this huge hill I had a hard time climbing last year, if I go with 5.13s I can get about 25.4 but I do drive it down the highway so I dont want it reving too high either.... I can always do a 3:1 swap in the future aswell... 36.3:1 with 4.88s

[scottjkj1]

Been running 40's with lockers for a couple of years now. As far as the 205 if your not worried about the lower range you cant go wrong, they are pretty much bullet proof.

[TAWL_BOY]

I ran the stock 241 with a JB conversions Super Short SYE with an 8" custom slip shaft to a divorced 205 and my driveshafts where equal lenth.(I had an ext cab short bed)

The main problem is that if you ran double low the 4L60E wouldn't shift. But a full manual valve body with solve that.

I can post pics when I get off of work.

[Rick1217]

I ran the stock 241 with a JB conversions Super Short SYE with an 8" custom slip shaft to a divorced 205 and my driveshafts where equal lenth.(I had an ext cab short bed)

The main problem is that if you ran double low the 4L60E wouldn't shift. But a full manual valve body with solve that.

I can post pics when I get off of work.


So it was a doubler? Yeah some pics of that would be good.

[Grumpy_old_fart]

Also one thing to keep in mind, I was researching and I found out the 2wd output shaft is the same one used on 4x4 models with np205s and My adapter might work from my np241/th400 so I can get a 205 to work without have to buy more parts and open the tranny up. So I can used the built tranny and just have to buy and bolt a np205 to it, I will for sure need new driveshafts but thats a given... After finding that out I might have to lean more towards the np205... it will be easier to swap it over so thats the main thing plus its alot stronger.
The gear ratio is not a big deal to me, I wouldnt mind abit lower but the 2to1 ratio is okay..... Im probably going with 4.88s in the new diffs so i will loose a little bit crawl ratio, but I think I have 24.9to1 with my set up now and Ill have about 24.2 after so no big deal, I like mud more than the rocks so i should be okay, although there was this huge hill I had a hard time climbing last year, if I go with 5.13s I can get about 25.4 but I do drive it down the highway so I dont want it reving too high either.... I can always do a 3:1 swap in the future aswell... 36.3:1 with 4.88s

you can make this work with the np241 output shaft, np241-th400 adapter, and short input for the np205, and a round case 205 case that originally came with the long input.

If you use the th400, you can get a 2.75 or 3.00:1 low gear set for it, but you will have to disassemble it to install it. the 3.00:1 gears for an NP205 require a new set of gears and a new case, as the gears will not fit in the stock np205 case.

If you have the 2wd output shaft, the longer racetrack adapter and short input 205, you can just bolt it together and go, after you build driveshafts. the roundfaced version might allow you to keep your driveshafts the way they are in the front. Since the rear isnt a slip yoke style (unless you get a later model with the VSS attachment), you would probably need to change the stock driveshaft for a longer rear driveshaft.


But i thought you knew all of that. There is always the option of installing a ford np205 and not worrying about it... especially if you have a drivers drop axle. they look like this:
http://img385.imageshack.us/img385/45/cassandramotorcycleridexg2.jpg

this would also work with the passenger drop round faced 205, using the short input, the stock np241 to th400 output and adapter. it just leaves the front output on the passenger side of the case, instead of the drivers side.

theres an NP205 thread around here somewhere (http://pirate4x4.com/forum/showthread.php?t=653713).

[Rick1217]

I was thinking of using the th400 with the 2wd shaft. All the 8 bolt racetrack np205s are the same? All I need then is that np205, and the adapter for it? Do you know off hand which year/model of trucks that style came in? just to make it easier at pick n pull.
Im probably going with a chevy dana 60 i can get one for about 550 in decent shape. I have yet to find a 78/79 ford d60 in my area and the newer ford d60 are all well over 1000 in my area. nothing is bought for the swap yet besides the 14ff so my options are still open though if i do come by a ford for a good price.

[Rick1217]

Some info I found ...

Bolt Pattern:
All GM NP205 cases 1971-1985 had a 8 bolt "racetrack" bolt pattern
All GM NP205 Cases 1986-up had a 6 bolt circular bolt pattern


32 spline (Short); 32 spl (Long): The units supplied with a T400 Automatic (also SM465 86-up) have a 32 spline female input. We have seen both a short (about 1.5 to 2.0" stickout) and long (more like 3-3.5" stickout) versions of this gear. This gear is directly compatible with the Klune-V Extreme Underdrive, which can be supplied with a 32 spline output shaft. Longer spacers are required with the long input.

Also see data on swapping input gears lower on this page.
1979 to 1985 GM NP205: 8 bolt "racetrack" bolt pattern:
During these years, the GM NP205 showed up behind Turbo 400 and SM465 Transmissions in 1 Ton trucks only.. 1/2 and 3/4 T trucks began to be supplied with the NP208 instead. SM465 units will still typically use the 10 spline input. Turbo 400 units have the stout 32 spline female input (in most cases the short 32 spl input, about 1.5-2.0" stickout) however still uses the 8 bolt "racetrack" bolt pattern.


So that means they might be a little harder to find at pick n pull, Does anyone know if the 8 bolt 205 came in pre 79 1/2 or 3/4 with a th400? All the stuff at my local pick n pull that is bigger than 3/4 is usually 2wd.

[TAWL_BOY]

I ran the stock 241 with a JB conversions Super Short SYE with an 8" custom slip shaft to a divorced 205 and my driveshafts where equal lenth.(I had an ext cab short bed)

The main problem is that if you ran double low the 4L60E wouldn't shift. But a full manual valve body with solve that.

I can post pics when I get off of work.
http://i141.photobucket.com/albums/r57/TAWL_BOY/yokeshaft.jpg

http://i141.photobucket.com/albums/r57/TAWL_BOY/205mounted.jpg

http://i141.photobucket.com/albums/r57/TAWL_BOY/casecradle5.jpg

[Rick1217]

How much lift are you running? Your front drive shaft looks like it would be close to touching the np241. Intresting set up though, Ive never seen the np241 useed for a doubler like that, I think i will just stick to one t-case myself though.

[TAWL_BOY]

It's about 32" of lift or so. This is my mud bogger.

But you could easily remove the guts for the 241s front output, hack off that part of the case and weld in a block off plate....or just run a passenger drop 208 and then there won't be a clearance issue for a drivers side shaft.

[Grumpy_old_fart]

Some info I found ...

Bolt Pattern:
All GM NP205 cases 1971-1985 had a 8 bolt "racetrack" bolt pattern
All GM NP205 Cases 1986-up had a 6 bolt circular bolt pattern


32 spline (Short); 32 spl (Long): The units supplied with a T400 Automatic (also SM465 86-up) have a 32 spline female input. We have seen both a short (about 1.5 to 2.0" stickout) and long (more like 3-3.5" stickout) versions of this gear. This gear is directly compatible with the Klune-V Extreme Underdrive, which can be supplied with a 32 spline output shaft. Longer spacers are required with the long input.

Also see data on swapping input gears lower on this page.
1979 to 1985 GM NP205: 8 bolt "racetrack" bolt pattern:
During these years, the GM NP205 showed up behind Turbo 400 and SM465 Transmissions in 1 Ton trucks only.. 1/2 and 3/4 T trucks began to be supplied with the NP208 instead. SM465 units will still typically use the 10 spline input. Turbo 400 units have the stout 32 spline female input (in most cases the short 32 spl input, about 1.5-2.0" stickout) however still uses the 8 bolt "racetrack" bolt pattern.



So that means they might be a little harder to find at pick n pull, Does anyone know if the 8 bolt 205 came in pre 79 1/2 or 3/4 with a th400? All the stuff at my local pick n pull that is bigger than 3/4 is usually 2wd.

TH400/np205's were one ton fodder. they were not used in 1/2 ton or 3/4 ton applications. pre 1980, 1/2 tons used the th350 and 3/4 tons used the th400/np203 combo. 1/2 ton, 3/4 ton and one tons used the sm465. after 1980, the np208 came into use in 1/2 ton and 3/4 ton applications. in 1980, and 1980 alone the np205 was the only transfer case offered.
Had you read the thread about NP205's, you would know that the 1.5 to 2 inch stickout shaft was an np241, the 3/4 inch stickout shaft was an np203 shaft, and the 4 inch stickout shaft was a typical 2wd output shaft... its all in there.

[Manch]

Run a dodge 241 with a fixed yoke(thats a factory option).Then I would take the planetery out of the 241c and slap it in the 241d,put a clocking ring in front of it,and your done.BTW use a 241d out of a 90 or 91 dodge 1/2 ton or a ramcharger.Im putting a left hand drop version of the same thing in my truggy.If you have any questions just pm me.