couple of issues

[jmpidgeo]

first off, 1995 chevy k2500 HD 6.5 TD 4x4

first problem
4 wheel drive is kinda screwy. 4hi works perfectly, and will shift into low range, but the front wheels do not kick in...i am thinking vacuum switch for the t-case? maybe? dunno.

second problem
when in 4 wheel drive, and turning (no matter what surface) it seems like i hear lots of noise coming from the front end, along with just an all around strange feeling. seems like it could be bad CV's...kinda jumps around (which i know is normal on dry) but i don't really know about the extent that mine does it, especially while on snow.

[JTodd]

I cannot offer advise about the 4-lo, but your experience with front end bind while in 4-hi sounds normal. Whether in 4-hi or 2-hi, the front axles are turning with the wheel, so any cv problems would be felt all the time. If there is a lot of jumping, or loading and unloading, check the play in your front hubs. But, again if this were the case, you would notice it all the time.

[Robyn]

Hi there

The T case has a switch on it that sends a signal to the computer as well as actuates the thermal actuator.
The thermal actuator is the little widget that heats up and a plunger pops out and engages the front end.

Most likely the T case switch is faulty in the low range position.
Not hard to replace.
There is no vacuum on this stuff.

Jack the sucker up and check the front CV joints well. They run all the time even in 2WD.

Pull the wheels and see what is going on.
The late trucks will make a little more front end noise while in 4X4 just because of the way the IFS center section is mounted.
Noise should not be bad and they should be smooth with no jumping and such.

The half shafts come out easily too, remove the center nut at the axle end (wheel) and the row of bolts at the inner flange.
The shaft unit should come out fairly easy from the truck at this point.