4WD Issues

[mah77]

I did a little reading here, and it led to an overwhelming amount of "issues" to check. Heres my problems:

I went up to the snow the other day, and had no problem putting the truck in 4 Hi, while driving on the snowy highway. I drove into a field (about 2' of snow), and parked. When I went to leave, the tires just spun. I noticed that only my passenger rear was spinning. I put it in N, then switched the dash selector to 4 Low. Same thing happened again. I got out, manually locked the hubs, and then my driver front, and passenger rear would spin, and the truck wouldnt go anywhere. Luckily a snow plow was passing, and he pulled me out. Once on the road, I switched back from 4 Low, to 4 Hi, and everything seemed to be just fine. It appears I have a problem with 4 Low. Im curious if its a vacuum issue (ie, pump, or leak in a line).

Part 2 of my issues, is my climate controls. Occasionally when I switch the vent on, the fan will come on full speed. I can then lower the speed manually and everything is fine. On other occasions, when I put the defrost on, the same thing (fan comes on full speed, then I have to manually turn it down). Ive also noticed that when I put the defrost on, itll kick on the a/c as well, which I have to turn off.

Due to some research here, Im thinking these two problems are related, and its most likely a vacuum issue. Is ther a way I can narrow it down to the pump, pulse vacuum solenoid, or just a leak in the lines? When i turn my ignition to "on" for the first time each day, I can hear the pump grind away for up to 45seconds, but with the noise from the engine, its hard to tell if/when it comes on while Im driving.

[kendallcschm]

Originally Posted by mah77

I did a little reading here, and it led to an overwhelming amount of "issues" to check. Heres my problems:

I went up to the snow the other day, and had no problem putting the truck in 4 Hi, while driving on the snowy highway. I drove into a field (about 2' of snow), and parked. When I went to leave, the tires just spun. I noticed that only my passenger rear was spinning. I put it in N, then switched the dash selector to 4 Low. Same thing happened again. I got out, manually locked the hubs, and then my driver front, and passenger rear would spin, and the truck wouldnt go anywhere. Luckily a snow plow was passing, and he pulled me out. Once on the road, I switched back from 4 Low, to 4 Hi, and everything seemed to be just fine. It appears I have a problem with 4 Low. Im curious if its a vacuum issue (ie, pump, or leak in a line).

Part 2 of my issues, is my climate controls. Occasionally when I switch the vent on, the fan will come on full speed. I can then lower the speed and everything is fine. On other occasions, when I put the defrost on, the same thing (fan comes on full speed, then I have to manually turn it down). Ive also noticed that when I put the defrost on, itll kick on the a/c as well, which I have to turn off.

Due to some research here, Im thinking these two problems are related, and its most likely a vacuum issue. Is ther a way I can narrow it down to the pump or just a leak in the lines? When i turn my ignition to "on" for the first time each day, I can hear the pump grind away for up to 45seconds.

my truck always puts he A/C on when i put defrost on and eveything is always full blast when auto is set.. thats normal behavior, on the snow its possible your limited slip just wasn't locking in.. try your 4lo on even ground and chances are you'll be fine

[mah77]

Thanks for the input. I figured the limited slip may be why only one back wheel was spinning, but does that apply to the front wheels? I typically keep "auto" turned off on my vents, but it tends to come back on every time I turn the vents on for the first time each day.

[kendallcschm]

Originally Posted by mah77

Thanks for the input. I figured the limited slip may be why only one back wheel was spinning, but does that apply to the front wheels? I typically keep "auto" turned off on my vents, but it tends to come back on every time I turn the vents on for the first time each day.

yea thats typical with the vents.. and you have an LSD in both front and rear.. so sometimes that can be the case and the buzzing sound when you first turn the key before starting is the fuel pump building pressure and such