75 W100 T-Case
All 70's were not full time full 4WD. If you have a devorced transfercase they are 2WD-4WD. I like them the best but, they are hard to come by. They do not use a chain they use gears. The down side with them is that they do not have as much of a gear reduction for low. My 72 has one in it. I think that 74 was the last year for them but, not sure, dont remember.
Now, if you put your truck in gear and the front shaft truns, does it speed up with giving it gas? Do you have lock-out hubs on the front? If so ingage them and see if the truck tries to go anywhere. I take it that the rear drive shaft does not turn. Have you tried to move the truck by pulling it? See if it will move while in park. If it moves and does not slide the tires you have a problem with your trans case as long as you are sure that your linkage to it is right and tight and not slipping when you are changing from 4wd high, 4wd high loc, N, 4wd low loc. With front shift turning and rear not turning, sounds like trans case for sure to me, also if you dont have lock out hubs front tires should be turning.
Now, if you put your truck in gear and the front shaft truns, does it speed up with giving it gas? Do you have lock-out hubs on the front? If so ingage them and see if the truck tries to go anywhere. I take it that the rear drive shaft does not turn. Have you tried to move the truck by pulling it? See if it will move while in park. If it moves and does not slide the tires you have a problem with your trans case as long as you are sure that your linkage to it is right and tight and not slipping when you are changing from 4wd high, 4wd high loc, N, 4wd low loc. With front shift turning and rear not turning, sounds like trans case for sure to me, also if you dont have lock out hubs front tires should be turning.
until you break the intermediate shaft right out of the truck in a mud hole... But this is a '75. OP has the front axle been swapped at any time? If it has lockout hubs or a axle disconnect in the middle of the longer axle shaft it is not compatible with your tcase.
I would try removing both driveshafts, putting the truck in drive, and seeing if both outputs will spin. If not, you have found your problem. If they do, it may be the rear end. Does the truck roll?
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Joined: Mar 2013
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From: NC
Just a question for Wombat, why is not compatible with his tcase? I have them on a 77 that is all time 4WD. They work just fine on it and I have had them locked in and the rear shaft out and drove it across the yard to move some wood up to the house.
To me if his front shaft spins with out spinning the front tires there is something wrong with the front end unless it has lockout hubs and the rear shaft does not try to turn then there is something wrong with the tcase also.
To me if his front shaft spins with out spinning the front tires there is something wrong with the front end unless it has lockout hubs and the rear shaft does not try to turn then there is something wrong with the tcase also.
I was assuming he had the case not locked up (the way it is designed to drive in the road) and saying that if the front axle has any kind of disconnect and is unlocked the diff in the tcase will divert all the torque out the path of least resistance and the truck will go nowhere. Just a thought to make sure the OP knows how his 4x4 system works.