[tman30]

pull the truck into 4x4, goes in nice and smooth doesnt grind or anything. light on the dash doesnt come on and the and the "shifter" is slide into 4x4 but the truck is still in 2wd. any ideas?

thanks,

 

[Off-road]

so is it in 4x4 or not? is it in andno light? check the bulb and then the switch on the steer axle if you have a cad unit. likely one or both is junkie....

 

[tman30]

so is it in 4x4 or not? is it in andno light? check the bulb and then the switch on the steer axle if you have a cad unit. likely one or both is junkie....

i pull the shifter into 4x4, but the truck still stays in 2wd

 

[Off-road]

check to see if you have a cad axle. if so, verify you have vacume at the cad unit, then verify when you switch 4x4 modes that it actually switches line with vacuum.

also verify that your shift linkage is hooked up, and all parts of the 4x4 are there.

most common issue is a broken vacuum line on this 4x4 setup

 

[millfire517]

My truck had this issue and it turned out the vacuum lines came unplugged under the transfer case.

 

[Off-road]

its bad enough for mine being 12 years old the vacuum lines getting brittle, yours at 15 is getting wosre.... check those lines carefully.

 

[bigfish95971]

Transfer case is fine. As above it is the vacuum lines, the vacuum switch on the transfer or the CAD on the axle. If it is the light alone the wire comes off on the switch on the CAD.

 

[dwayne1002]

Its also a good idea to take off the cad module on the axle turn it upside down and soak it with wd40 or other lubricant for a couple of hours once a year. Slide it back and forth by hand to ensure smooth action. Had a couple trucks i fixed where i had to beat the slider with a hammer to break it free.

 

[Off-road]

Its also a good idea to take off the cad module on the axle turn it upside down and soak it with wd40 or other lubricant for a couple of hours once a year. Slide it back and forth by hand to ensure smooth action. Had a couple trucks i fixed where i had to beat the slider with a hammer to break it free.

never seen that before.... did they just not use 4x4 ever, or was the diff low on oil? do you be chance know the root cause?

 

[dwayne1002]

Id guess they used 4x4 infrequently but im not sure. They had plenty of oil in the diff but there is not really a good slinger to throw the oil up on the shaft regardless. You can see the surface rust on the shaft that attaches to the diaphragm. It makes it bind up and kinda jumps instead of a good crisp action.

 

[NCC74656]

i have an issue with my 4X4 where it does not disengauge on the first shift. so im in 2WD, shift into 4X4 and it goes right in. then i shift back to 2wd and it stays in 4 untill i shift it back to 4 and then back to 2. after that second shift it pops out every time... kinda odd.

 

[Off-road]

Might be that the axle is binding slightly. If you try steering or hit the brake it helps unload it. See if that helps.

 

[bigfish95971]

Is that on the move or sitting still. It should be shifted in and out of 4x4 hi on the move, and barely rolling for low if having difficulty stopped.

 

[tman30]

main line came off the power steering pump, all good now

 

[bigfish95971]

I assume you meant the main line came off the VACUUM pump which is attchecd to he PS pump.

 

[Off-road]

Is that on the move or sitting still. It should be shifted in and out of 4x4 hi on the move, and barely rolling for low if having difficulty stopped.

that is dead wrong. you can shift to high moving or stopped, no issues either way.

as for low range, it should never be shifted when moving, only in neutral. there are reasons for this. the low range is activating a set of sun gears. the gear drop is not synchronized, thus attempting to shift it while moving can cause serious damage to the transfer case. you put the truck in neutral so the input (easiest shaft to turn) can align itself with the output shaft, and four wheel drive output. then the vacuum pulls in the slide collar.

to shift to low any other way will cause damage and this damage is cumulative over time.

dont believe me read your owners manual.