fulltime conversion to parttime.

I have a 74 Chevy 1/2 ton 4x4 with a fulltime front diff. I converted it to part time with a set of Warn hubs. The problem is with the hubs in "Free"
position, the truck doesn't move. It feels like it wants to but does not. After putting the hubs in "Lock", it drives fine. I talked to Warn and they told me there is a "Transfercase conversion kit" that fixes this. Unfortunatly, the guy at Warn did not know how to come accross one. Can anyone help?!?!? Is there such a thing? Does anyone have any sources or ideas? Anything would be very much appreciated. Thanks,
Louis
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Yes you need a way to set up the transfer case so it will run with the front end unhooked. Just adding hubs will not do it. http://custom4x4.tripod.com/milemarker_page2.htm gives you a look at the NP203 case (probably what you have) and how it is done. http://www.milemarker.com/4x2conversion.html http://www.tellico4x4.com/catalog/index.php/cPath/2880_87_570
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Steve W. wrote:

You have to be carefull on how you mod it to because a few kits out there effect oiling in critical areas and can shorten Tcase life. If you use straight 30w in Tcase (which is spec and 20w in winter) and 75w90 in axles, it will not drag down too bad MPG wise.
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Crazy_J02 wrote:

    My advice, get a NP208 or NP205 Transfercase and get away from your NP203 with diff in case. When in "lock" it locks the center diff ands sends 50% of power to each axle set. In rugular hi or low range it sends the power to the wheels with the least amount of grip. Charles
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Charles Bendig wrote:

Actually when lock it does no power division as it can send 100% or the torque to either drive shaft as needed. When unlocked, it divids the torque equally front to rear as a pure differentail and do nothing else. I have a old J20 with full time and I love it for off road because 90% of the time I do not even need to lock it yet have added traction over 2wd without the drive line bind. It was great plowing snow and I rarely needed to lock it for that too.
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TheSnoMan wrote:

    We used to have a 78 K-20 Suburban that had a 203, and was a plow truck. It also doubbled as a Hunting, Fishing, and road trip truck. The 203 is just fine for that. Yet when you are doing what the OP wants to do, use lock outs on the front diff. It's alot less effort to just swap transfer cases for one that is made for that.
    Most NP205 trucks had lock-outs when delivered from the factory. I beleave some NP208 trucks did as well. The factory GM stuff for those trucks is perdy decent.
    Now if I can just find me a K-35 Cab and Chassis with the orginal Dana 60 in front. Charles
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Charles Bendig wrote:

Actually front lockout hubs where a option back then with a NP205, not standard. GM sold not 203 with a stick that I am aware of but a few automatic got out the door with 205's durring 73 to 79 when the 203 was standard when a automatic was ordered. If you could find a clean 73 thru 79 truck with a 203, it would still make a great plow truck even today.
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J20 uses a "Quadra trac" if memory serves, different NP###....I forgot the New Process model number.........I had the NP203 in several Dodge Ramchargers we had. When in "Hi" or "Lo" the differential is in normal mode, approx 60% of power goes to rear and 40% goes to front. This is the normal driving mode. If you do not have a limited slip rear end and you get is some serious mud it is easy for one rear wheel to start spinning and all the torque will go to that one wheel that is spinning. That is the reason for the "Hi Loc" and "Lo Loc". When in either it isolates the center differential and locks both together and will be a 50/50 torque split between the axles. New Process was the gear division of Chrysler that made the NP203 for Chevy/GMC, Jeep,Ford, Dodge and Plymouth. (Remember the Plymouth Trail Duster, clone of the Dodge Ramcharger). Jeeps had a single low range lever that came up out of the floor board next to your right shin, looked like a windshield wiper lever. They didn't use the regular transfer case shifter the rest used.New Process was sold off with Dana from Chrysler in the early 80's. Just putting a Warn Hub assembly on a full time set up will do exactly what happened in the post. All the torque will go to the front spinning hubs, and since the hubs aren't locked in the front wheels aren't going anywhere. Also you are not going to increase the mileage that much by going to a part time setup from a full time. You may get an additional mile or two per gallon, but the labor, parts and headache aren't worth that.

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Actaully is was a Borg Warner BW 1339 (Quadratrac) back then. It is possible to swap a Dana 20 into its place without too much fuss. YOu are off on the power split. When it is lock it will send the torqie where it is needed (where the traction is), there is no 50/50 split as the driveshaft are locked together and each one can take as much (or as little) power as needed. A unlock differentail mode is 50/50 on torque split because it can do it no other way. People seem to get confussed about this one a lot.
Mark & Sharla Thompson wrote:

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Thanks for all the advice. It is very helpfull. I do have another question. Why is it when my front driveshaft is removed, the truck will move without a problem? Is this not the same as unlocking the hubs?? I am really confused on this one. Let me know what you think. Thanks,
Louis
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Thanks for all the advice. It is very helpfull. I do have another question. Why is it when my front driveshaft is removed, the truck will move without a problem? Is this not the same as unlocking the hubs?? I am really confused on this one. Let me know what you think. Thanks,
Louis
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Crazy_J02 wrote:

    You drive your truck with out the front drive shaft in? E-Fack-Gads. Do you happen to live in Xiena Ohio, and have "Semi Stacks" running up thru your truck bed?
    As to why it will work that way. No front shaft means no drag from the gears, axles, brakes, ect. With a differential, one size with NO Drag will enable all the power to the other side. Just like if you have a locking rear diff, and pull the right axle compleatly out on a truck where the axle is bolted the brake drum, or the axle is bolted to a wheel hub. Take that axle out and the left rear gets full power, unless your loacker is toast. Charles
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