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73-87 Chevy _ GMC Trucks => 4 Wheel Drives => Topic started by: Magic1 on April 15, 2013, 10:53:44 am
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Ok. So after checking into the cost and parts needed to swap transfer cases I've decided that the best route for me is to just keep my 203 tcase and use it as it was meant to be. It's still a full time case but for some reason the po put manual lockouts on the front. I'm guessing due to the fact that maybe it was cheaper than replacing the original type slugs that were there to begin with. So my first question is will it hurt anything to keep them locked all the time while driving (replicating the original setup) and with it being full time 4x4 as long as I keep it in high and not high lock can I drive at any highway speed without damaging the tcase or anything else? I know it sounds like a dumb question but I'm just used to the more modern tcases where you should only run up to about 55 mph when engaged. I'm assuming with the differential in the tcase that its ok but for peace of mind I want to check first. I know I can install a part time kit but I don't use this as a daily driver and kind of like the idea of having all wheel drive. Call me crazy. Lol. I'm only getting about 8-9 mpg now so I don't guess gas mileage will matter much.
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If the front hubs aren't locked the truck won't move.
These were designed to run highway speeds, so you should be ok.
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Well I'm confused now. Lol. I run the truck with the hubs unlocked all the time now and it will move in high and low but will not in either lock position. So does this meen that my case has been converted? From everything I've read it says that when your case is in high with the hubs unlocked with a part time conversion you can spin the front shaft by hand. Is that info wrong? The case is in need of a rebuild but I'm really interested in trying to figure out exactly what's going on with it first. With the hubs locked it will move in any position. On another note, 203 cases are readily available around here and cheap so if I wanted to buy a used one and swap it out instead of paying to have mine rebuilt, is there any way to see if another used case is in good working order without having to do the install first and checking it in the truck?
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I guess what I should be asking is if my case has been converted, what would be the proper operation of it as far as keeping the hubs locked and going through the gears/which gear to use and when?
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On a 203 case when not in lock power is going through the differential in the case (an open differential). When in Lock the power is directly going to both axles. If the case has not been converted and if you have the hubs unlocked and the transfer case not in lock the truck will not move. If you leave the hubs unlocked and put the transfer case in lock your front shaft is still turning the front differential but disconnected at the wheel. So, your still spinning everything, witch I don't think spinning a "loose" drivetrain is the best on parts in the front axle. And not recommended on a 205 transfer case. If you have the conversion done to the transfer case, witch locks the differential in the transfer case, while in a non lock position the power is only going to the rear. The front will be completely disconnected in the transfer case. One cool benefit with the conversion is you will gain a 2 lo position. The new pattern would be..
4 lo
2 lo
N
2 hi
4 hi
I hope this helps...
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On another note, 203 cases are readily available around here and cheap so if I wanted to buy a used one and swap it out instead of paying to have mine rebuilt, is there any way to see if another used case is in good working order without having to do the install first and checking it in the truck?
You can shift it on the ground and turn input and output shafts. In my opinion, it would be a good idea to do a thorough inspection before you install it, even if you have to open it up. The NP203 is pretty darn heavy and I would rather know the chain and bearings and so forth are in good condition before trying to jockey it around under the truck...
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Haha. It is heavy. That's what I was trying to find out was just what I can do first to see if it was in good working order before installing it. I'm a pretty decent sized guy but I don't wanna try and manhandle 200 lbs anymore than I have too. Lol. How deep would you need to dig into it to check? I've rewired the truck and put the motor in myself but haven't got a clue about transmissions or tcases. Don't wanna pull it apart to have parts fly everywhere and not know how to put it together again.
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there was a write up on someone swapping chains and a tear down