I have a 1975 K5 blazer. I’ve identified that I have the always-on 4wd transfer case that was offered for that year. My understanding from research is those trucks didn’t come with manually locking hubs. That said mine does have manual locking hubs. I think I read that this is a mod so that you can shut off the always-on 4wd and drive around town in 2wd. Hoping someone can confirm all this and provide any additional information. I’d test things myself but my front drive shaft was removed by the previous owner. Looking to see if all I need is a drive shaft to get my 4wd back and also if those aren’t the stock hubs, what are they off of if I need to replace them or whatnot. Thanks!
CK5
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Transfer case/hub question
- Thread starter Damufuer
- Start date
It’s possible that the previous owner installed a part-time kit in your originally full-time New Process model 203 transfer case and all is well with the manual hubs.
Or, and this happened a lot back when these trucks were newer and on the road as daily drivers, they could have just installed manual hubs and pulled the front drive shaft and put the T-case in 4-High ( the drive shaft would be pulled to keep it from spinning ).
Knowing the exact position of the T-case lever can help identify if the later has been done as well as knowing if the front output yoke on the T-case will spin freely while the transmission is in park?
Or, and this happened a lot back when these trucks were newer and on the road as daily drivers, they could have just installed manual hubs and pulled the front drive shaft and put the T-case in 4-High ( the drive shaft would be pulled to keep it from spinning ).
Knowing the exact position of the T-case lever can help identify if the later has been done as well as knowing if the front output yoke on the T-case will spin freely while the transmission is in park?
Great thanks. I can test those things tomorrow. What is involved in installing the part-time kit you mentioned? I assume that simply putting the manual locking hubs on isn’t that. If there isn’t the part-time kit installed, what would be the purpose of putting these hubs on?
Back in the day of full-time transfer cases fuel economy was of great concern - also, sometimes folks wanted to keep wear and tear down to a minimum so doing away with the constant “all-wheel-drive” condition seemed to help.
For most of the 70’s a NP-203 was standard equipment on automatic Chevy trucks and that was not always desired.
The hubs would allow the front axles and differential and related components to stay stationary instead of being driven all the time.
A part-time kit might be a little much of a project all depending on one’s mechanical ability.
Parts for a NP-203 are getting expensive so weigh your options first.
For most of the 70’s a NP-203 was standard equipment on automatic Chevy trucks and that was not always desired.
The hubs would allow the front axles and differential and related components to stay stationary instead of being driven all the time.
A part-time kit might be a little much of a project all depending on one’s mechanical ability.
Parts for a NP-203 are getting expensive so weigh your options first.
The NP203 has an open differential between the front and rear outputs when in the High and Low positions. That allows for driving on pavement with AWD. The High Lock and Low Lock positions lock that differential together similar to normal 4wd tcases and is only for off-road use.
The part time kit removes the open differential and disconnects the front output from the rear completely, more like the conventional tcase in 2wd.
To test what you have, you only need to put the tcase in High range. If it moves with the front driveshaft missing, it has a part-time kit. If it doesn't move with the front driveshaft missing, it is still a stock open differential.
The part time kit removes the open differential and disconnects the front output from the rear completely, more like the conventional tcase in 2wd.
To test what you have, you only need to put the tcase in High range. If it moves with the front driveshaft missing, it has a part-time kit. If it doesn't move with the front driveshaft missing, it is still a stock open differential.
So you have no front driveshaft? Like Kenny said that's easy, if the truck is in hi and its moving its been converted, if it has to be in hi loc to move then it hasn't been converted and driving it like that is not good for the case. Also be aware that if you have an unconverted case and you install a front driveshaft but don't lock the hubs in, the truck can roll away if parked on a hill.
