help with 4x4
#12
Is this line tied to the dipstick for the trans?? Mine has a cap on it and my 4x4 doesn't engage, vacuum always on (can be seen in the actuator). I know chances are the vac switch is bad (already tried 2wd/4wd + trying to move the front driveshaft, all is good).
Would the cap on cause the vacuum to always be on?
Here's what Im talking about :
http://i85.photobucket.com/albums/k7...r/DSCF2885.jpg
#13
Is this line tied to the dipstick for the trans?? Mine has a cap on it and my 4x4 doesn't engage, vacuum always on (can be seen in the actuator). I know chances are the vac switch is bad (already tried 2wd/4wd + trying to move the front driveshaft, all is good).
Would the cap on cause the vacuum to always be on?
Would the cap on cause the vacuum to always be on?
#14
so both of those should be breathers? the one on the fan shroud and the one by the heater hoses? what was i looking for in the check valve? today i jacked up the entire truck put it in 4wd and in drive and the shaft from the xfer case to the front diff was running so i know the xfer case is working and i know the front end is the problem the actuator should that depress all the way or just a little bit?
#16
Yes, both are vents, not check valves. The one by the fan shroud prevents the front differential from building up pressure. The one by the trans dipstick tube vents vacuum in the axle actuator to atmosphere and releases the axle actuator.
The front driveshaft turns whenever the vehicle is in motion, 2WD or 4WD HI, doesn't matter. Driving in 2WD the transfer case is applying power to the front differential however, the power can't get to the ground until the right axle locks in. This is what allows "shift on the fly" into and out of 4WD HI. When you select 4WD HI at the dash switch, the encoder motor moves the linkage inside the transfer case and operates the vacuum switch for the front axle actuator. The right front axle locks up with the differential and the differential is live. This called a mode shift.
Selecting 4WD LO is called a range shift and the vehicle must be stopped while the encoder motor changes the gear range in the transfer case.
EDIT: With the engine running, transmission in PARK, 4WD selected, there should be manifold vacuum at the axle actuator and the cable should pull in about 3/4". When you select 2WD the actuator should release the cable immediately and there should be no vacuum at the actuator.
The front driveshaft turns whenever the vehicle is in motion, 2WD or 4WD HI, doesn't matter. Driving in 2WD the transfer case is applying power to the front differential however, the power can't get to the ground until the right axle locks in. This is what allows "shift on the fly" into and out of 4WD HI. When you select 4WD HI at the dash switch, the encoder motor moves the linkage inside the transfer case and operates the vacuum switch for the front axle actuator. The right front axle locks up with the differential and the differential is live. This called a mode shift.
Selecting 4WD LO is called a range shift and the vehicle must be stopped while the encoder motor changes the gear range in the transfer case.
EDIT: With the engine running, transmission in PARK, 4WD selected, there should be manifold vacuum at the axle actuator and the cable should pull in about 3/4". When you select 2WD the actuator should release the cable immediately and there should be no vacuum at the actuator.
Last edited by Captain Hook; 11-27-2011 at 09:25 PM.
#17
yeah i never have vacuum at the actuator i already tested that out but on that check valve you told me to locate what am i checking for? should my next step be to pull the cover off the front diff? Side note would a bad Wheel Bearing on the passenger side cause this problem? i didn't think it would but just throwing that out there.