I don't have a K5 but you guys sound like you can help me. It is a 79 chevy LB PU TH350 with a 203 TC that will not go into 4X4. I do not know all the history of this truck but it has manual hubs and I assume the part time conversion kit because it will pull with the hubs unlocked. The TC will shift into low range and pull but when shift to LOW LOC it jumps out. Both high and high loc work but the front axle never pulls. I check the hubs by jacking the front off the ground , locking the hubs and the front drive shaft turns when the wheels are turned. Where do I start, with the conversion kit, linkage or somewhere else. I would like to have an idea where to start with out just taking things apart and guessing. It is a beater, I drive it less than 500 mi a year but I would like the 4x4 when I need it. THANKS
CK5
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203 tc help
- Thread starter notak5
- Start date
royjones
Trucker upper
ok
If it jumps out . then i would check the linkage . you can do it under the truck but i took the tranny hump out on mine and found the nuts where lose on the linkage it should be a full time case unless some one has put a part time kit in it hope this helped
If it jumps out . then i would check the linkage . you can do it under the truck but i took the tranny hump out on mine and found the nuts where lose on the linkage it should be a full time case unless some one has put a part time kit in it hope this helped
royjones
Trucker upper
Does it do it in both hi and lo loc
GMC1977
1/2 ton status
i had a 203 do something like that to me. it was the gear that is supposed to lock in the shaft inside the t-case and it wouldnt push the gear back far enough.
royjones
Trucker upper
Ok then time to look for a 203 I just gave one away
owenst7
1/2 ton status
Take the shift rod off the rearmost tab on the case. That's the tab that moves the shift fork for the differential. Lift the front tires up and shift that tab manually, I believe you need to push the bottom to the front of the truck. If it Locks the driveline then your shifter needs to be worked on.
The shifters wear out and don't hold hi or lo lock position well. Short of a catastrophic failure inside, there's really nothing Internally that would make it fail like your describing but still operate in 2wd.
If you pull the tailcone off you can work on the differential easily. You can actually remove all the internals related to this that way very easily.
The shifters wear out and don't hold hi or lo lock position well. Short of a catastrophic failure inside, there's really nothing Internally that would make it fail like your describing but still operate in 2wd.
If you pull the tailcone off you can work on the differential easily. You can actually remove all the internals related to this that way very easily.
broke73
1/2 ton status
The best way to get thing working smoothly and eliminate any doubts it's the shifter:
Put the shifter in neutral.
Preferably have someone in truck to hold it in place while you get the linkage off the 2 tabs on the Tcase.
The tabs should line up straight down and you shuld be able to stick a pin thru the hole in both tabs.
Now adjust the linkages to fit the tabs without moving the shifter from the neutral location.
If you still have that problem, maybe something happened in the case like a chain broke, it's not common but it has happened, to me to be exact.
If that hpened you will need to take it appart or get another one.
