4x4 trouble

[FishFind]

Yeah I did but it seems to be pulling it from the tranny I am guessing. The tranny fluid level goes down and the transfer case fills all the way up

[old_master]

Double check vacuum at the actuator under the battery tray, (to make sure the vacuum switch is working correctly). Engine at idle, when 2WD is selected there should be zero vacuum at the actuator. When 4WD is selected there should be manifold vacuum present at the actuator.

In 2WD the vacuum switch connects the actuator to the vent line and it must be clear: no oil, no kinks, no leaks, and the filter at the end of the vent line, (on the transmission dipstick tube) must be clear. To test, pull the vacuum line off the actuator, engine at idle, 2WD selected, you should be able to blow/suck on the vacuum line with very little resistance, and hear the air flow at the filter.

[FishFind]

I will have to wait till I get enough time to take out the battery and such. Is this the only possible way I can be getting the fluid in my transfer case?.

If so I may just replace the lines as I check them to make sure.

It seems to end up in there at a fast rate. After about 1 day the tranny is 2qts low and the transfer case is 2 qts overfull.

[old_master]

There's a seal at the transmission output shaft and one at the input shaft of the transfer case. Physically they are less than 4" apart. There's a fiber gasket between the two units where they bolt together. The purpose of the gasket is to keep dirt out, not to keep fluid in, (the seals do that). The only way the fluid can transfer from transmission to transfer case is if there is a negative pressure, (vacuum) in the transfer case strong enough to pull the fluid past the seals. The only way for vacuum to get into the transfer case, is if the vacuum switch is leaking vacuum past the seals inside the switch, or for some odd reason there is vacuum applied to the steel vent pipe on the top of the transfer case. I am not an artist, never claimed to be, bare with me on the rough, and I do mean rough, drawing:

[FishFind]

Thank you for doing that for me. I know for sure that vac line to HVAC looks dry rotted but have not seen any problems with my ac. I will dissconnect the lines and see what I find in them.

If I find fluid in them and clear them out do you think this can stop my transfer case overfilling? Granted the new switch I got is good?

[old_master]

If/when fluid gets in the HVAC lines, it will cause slow or no operation of the blend doors. It will not affect the 4WD system. The HVAC system has its own separate vent to atmosphere in the dash.

[FishFind]

Ok, well I did not have time to disconnect and check all the lines today but I did go around and locate them so I can check them later. I'll keep you posted.

[FishFind]

Got to check them and they seem to be free of fluid. I am not sure how it is getting in there.

One new thing happened to me. I got my truck stuck and I then put it in 4x4lo because my front tires where on good ground. My light said I was in 4x4lo and I heard the clunk under my seat near the transfer case but the front tires did not move at all. I tried 4hi and same thing.

I guess my question is was the 4x4 not engaging because the front tires where not rolling??

If so and I get it in 4x4lo can I come to a total stop and will it be in 4x4 right from take off or will it need to be rolling again to engage.

[old_master]

Right front axle shaft is not engaging to differential. Engine at idle, select 4WD, actuator under battery must have manifold vacuum and pull the cable ~1/2" to ~3/4".

[FishFind]

Ok I will pull that batt and check..


If it does move what do I do next>]?

The light on the selector lights up solid and I hear the transfer case engage.

If I put the truck on jack stands and hit the 4hi button will I see the tires spin or do they have to be rolling on the ground to engage?

[old_master]

Here's an easy way to see if the right front is engaging:
Engine at idle, select 4WD, raise only the right front wheel off the ground, it should not turn by hand. Select 2WD and it should turn freely.

[FishFind]

soon as I get the little ones down I check it out

[FishFind]

Here are the findings. after I took out the battery I noticed that the actuiator and the cable where not connected. I took a look and it seems that the little lock spring that came with the actuator did not do a good job. After a little adjustment to the spring I was able to get it to lock on to the actuator and then tested if the wheel locked and I am back in business. Thank You.

[old_master]

Good job! Glad you found and fixed the problem. Thanks for posting back.

[FishFind]

Hey I noticed that when I use the 4x4 the tranny fluid drops a lot faster. I think the transfer case heats up and dumps the fluid out the overflow line and then it draws it from the tranny again to refill. What is causing it to draw the fluid from the tranny??
I changed the vac switch and was able to blow through the vac line on actuator easy.