73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => 4 Wheel Drives => Transfer Cases and Front Drivelines => Topic started by: frickenbored on March 03, 2010, 01:53:54 pm
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Hello everyone, I have a 1988 Chevy K5 blazer (I know its not 73-87 but its the exact same body style) From the factory this truck came with a TBI 350, 700r4, and np208 transfer case. Fast forward to 2008 when I bought it for $1000 it had a 1985 TBI 305, 700r4, and 1979 np203. Fast forward again to 2009 It now has a 1969 383, th350, and still the same np203. Anyway my question is about the 203. When I bought the truck it had one 4wd shifter which only put it in 4wd or 2wd, and it had manual locking hub on the front axle. A week later when I was messing around with the exhaust I discovered a second shift lever sticking out of the transfer case. I cut a hole in the floor and and set up a second shifter handle. I descovered that this shifter put the transfer case in either lo gear, neutral, or hi gear. So this is the configuration for my shifters.
Shifter 1
2wd
4wd
Shifter 2
Hi
neutral
low
So i'm wondering if this tcase has been converted to a part time case. I've been driving around in 2 hi with teh hubs unlocked and I've shifted into every gear that the tcase has with the hubs unlocked and the truck has moved everytime. Correct me if i'm wrong but wouldn't the transfer case just send all of the power to the front axle if the hubs were unlocked since there is no resistance there? Also why does this 203 have 2 shift levers. Heres a pic of my shifters:
(http://img695.imageshack.us/img695/3977/allblack.jpg) (http://img695.imageshack.us/i/allblack.jpg/)
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THE 203 SHOULD BE
2 LOW LOCK
2 LOW
N
4 HIGH
4 HIGH LOCK
BUT NOT SAYING YOU DON'T HAVE ONE MY BUDDY HAD A 88 WITH THE SAME T CASE AS YOUR SAYING WITH 2 HANDLES I ASK HIM TOMORROW WHAT WAS UP WITH HIS I WANT TO SAY IT WAS A 205 BUT I THINK THAT'S WHAT IT WAS AFTER HE SWAPPED OUT TRANSMISSIONS AND T CASE ONCE HE BLEW UP HIS. TAKE SOME PICS OF THE T CASE AND POST THEM IF YOU WOULD
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Any new pics. I think me buddys was a 205
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i don't think any of the transfer cases came form the factory with 2 handle for the t-case. looks to me like someone did a twin stick conversion to your transfer case. i have done the twin stick conversion on a couple 205's, never on a 203 or 208. all it entails is taking the linkage apart at the transfer case and running 2 "shifting shafts" up into the cab so you can select 2wd high and low (without engaging the front driveshaft) and 4wd high and low. nice thing to do for offroad applications.
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Heres an old pic of my transfer case, Its for sure its a 203 because the tag says it.
(http://img687.imageshack.us/img687/3152/img1826u.jpg) (http://img687.imageshack.us/i/img1826u.jpg/)
So the dual shifter thing makes sense, it probably wasnt ever converted to a part time transfer case but with the dual stick design it acts exactly like a part time case. I can drive in two wheel drive hi all day with the hubs unlocked and the front drive shaft never turns. Will I cause any damage to the transfer case by using it this way?
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I also have another question, I'm swaping my 700r4 to a th400. I know that I have to swap out my 203's input gear from a 27 spline to a 32 spline. Question is are all the input gears the same? I've read that all 203 input gears can be swaped into the same case. I could just go to a 205 but for some reason I like the 203, its beefy, it internal gears are huge and I don't think their gonna break anytime soon and the chain is massive. For anyone whos never seen the guts of a 203 here you go:
(http://img692.imageshack.us/img692/6719/img1829u.jpg) (http://img692.imageshack.us/i/img1829u.jpg/)
(this is not the 203 from my truck, this is an older 1973 np203 that my neighbor gave me for a spare)
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Sorry bud can't help u out for sure but I think they can. From what I read you can swap out most of the part
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So the dual shifter thing makes sense, it probably wasnt ever converted to a part time transfer case but with the dual stick design it acts exactly like a part time case. I can drive in two wheel drive hi all day with the hubs unlocked and the front drive shaft never turns. Will I cause any damage to the transfer case by using it this way?
nope won't harm a thing. in reading your earlier posts, did you say you couldn't find neutral in any of the shifter positions? even with the twin sticks, you should have a transfer case neutral.
I also can't provide any help with the input spline, but where are you getting the new spline from? should be able to compare the two....
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So the dual shifter thing makes sense, it probably wasnt ever converted to a part time transfer case but with the dual stick design it acts exactly like a part time case. I can drive in two wheel drive hi all day with the hubs unlocked and the front drive shaft never turns. Will I cause any damage to the transfer case by using it this way?
nope won't harm a thing. in reading your earlier posts, did you say you couldn't find neutral in any of the shifter positions? even with the twin sticks, you should have a transfer case neutral.
I also can't provide any help with the input spline, but where are you getting the new spline from? should be able to compare the two....
No i have neutral. The second shifter goes from Hi, to neutral, to low. Well if my dual shifter set up wont hurt anything then i dont see any reason to go ahead and buy a part time conversion kit since it basically already is part time. The only place i can find the new 32 spline input shaft is here: http://www.northwestfab.com/input.html their out of Canada. And they are the only people that I can find that actually make and carry the factory adapter for the th400/np203: http://www.northwestfab.com/th400adaptors.html
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My truck has a twin stick setup like yours. but mine has the part time conversion done to it. the guy i got it from broke the stock linkage and made a twin stick setup to replace it. said he hated the factory setup. something about it binding all the time or something.
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My truck has a twin stick setup like yours. but mine has the part time conversion done to it. the guy i got it from broke the stock linkage and made a twin stick setup to replace it. said he hated the factory setup. something about it binding all the time or something.
Because he didn't lube it frequently. That always took care of my stiff shifter.
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Northwestfab is a great bunch of guys, with great products. You won't be dissapointed. They are sometimes hard to get ahold of, so be patient, you may have to call twice.
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acutally It turns out that I don't need anything from northwestfab. I found a th400/np203 adapter on ebay for $90 so I picked that up. Then I found a trans shop in Lousiana that sells a 27 spline th400 4x4 output shaft. Since I'm throwing a heavy duty rebuild kit at my th400 I bought that shaft too. And I picked up a 32 element intermediate sprag for the 400. Anyway now I don't have to get the np203 input shaft saving me time and money from rebuilding my transfer case. After I pickup my 3000 stall torque converter and the kick down setup I'll be all set.
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so just to be sure If my 203 wasnt converted to a full time transfer case then when I put the first stick into 2wd and unlocked the front hubs the truck wouldn't move at all? Since all the power would be going to the unlocked axle.
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Right
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its converted, I removed the rear housing today just to see. This is the kit that was installed:
(http://img143.imageshack.us/img143/3546/203w.jpg) (http://img143.imageshack.us/i/203w.jpg/)
Has anyone ever used this kit? When I inspected it I saw that the bearing that is supplied with the kit was destroyed, so I just ordered the kit again since its only $20 for a new bearing and thrust washers.
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Ok so heres what I don't understand...
(http://img37.imageshack.us/img37/8108/cogwm.jpg) (http://img37.imageshack.us/i/cogwm.jpg/)
The mile marker shaft conversion kit sits right on top of that cog type sleeve and is a solid shaft that when installed correctly has very little endplay after everything is done. So how does that shift fork move? It can't push up on the new shaft. With my np203 I have the shifters seprated and one of the shifters moves that fork up and down.