Front Wheel Drive Not engaging

[SneakerZed]

I am trying to locate the "Why" the front wheel drive is not engaging. I used P2P program and watched the animation on the front axle lock circuit.

I am using the transfer case shift lever in all operations below, the front wheel drive engage located on the dash need replacing and i have ordered a replacement.

I removed the drive shafts so we didn't have to jack the entire truck up off the ground.

This is what I know:
- I removed the Interlock Air Cylinder and the spring inside is pushing the rod "out" or into the transfer case, so I am assuming that once air pressure is applied it pushes the rod all the way in and locks it in place and does not allow it to "ride" over the "notches"

- I removed the Front Wheel Drive Air Cylinder and was able to manually push "rod" to move transfer case clutch forward and engage front-wheel drive so that when I manually spin the back of the transfer case connected to the rear wheels the "plate" that the front drive shaft connects to spins

- I capped the airline going to the Interlock Air Cylinder to temporarily bypass it so that it won't lock into place.

So, with the Interlock Air Cylinder bypassed I put the transmission in neutral and use the transfer case shift lever and put it in low and it does not engage the front wheel drive. I disconnected the air going to the front wheel drive cylinder and again used the transfer case shift lever to put in in low and air came out of airline - so air is getting to it but I do not know what the air pressure is or how much is needed to push it.

Can I purchase an air gauge locally that i can attach to check air pressure at various points to help narrow things down and where do I look to see what the air pressure should be at the interlock solenoid and front wheel drive air cylinder?

Any pointers would be greatly appreciated.

 

[simp5782]

I am trying to locate the "Why" the front wheel drive is not engaging. I used P2P program and watched the animation on the front axle lock circuit.

I am using the transfer case shift lever in all operations below, the front wheel drive engage located on the dash need replacing and i have ordered a replacement.

I removed the drive shafts so we didn't have to jack the entire truck up off the ground.

This is what I know:
- I removed the Interlock Air Cylinder and the spring inside is pushing the rod "out" or into the transfer case, so I am assuming that once air pressure is applied it pushes the rod all the way in and locks it in place and does not allow it to "ride" over the "notches"

- I removed the Front Wheel Drive Air Cylinder and was able to manually push "rod" to move transfer case clutch forward and engage front-wheel drive so that when I manually spin the back of the transfer case connected to the rear wheels the "plate" that the front drive shaft connects to spins

- I capped the airline going to the Interlock Air Cylinder to temporarily bypass it so that it won't lock into place.

So, with the Interlock Air Cylinder bypassed I put the transmission in neutral and use the transfer case shift lever and put it in low and it does not engage the front wheel drive. I disconnected the air going to the front wheel drive cylinder and again used the transfer case shift lever to put in in low and air came out of airline - so air is getting to it but I do not know what the air pressure is or how much is needed to push it.

Can I purchase an air gauge locally that i can attach to check air pressure at various points to help narrow things down and where do I look to see what the air pressure should be at the interlock solenoid and front wheel drive air cylinder?

Any pointers would be greatly appreciated.

Get rid of the air interlock solenoid. Run a line from the switch directly to the front axle engagement on the rear of the transfer case behind emergency brake. This bypasses all of that. You flip the switch you have 6x6. It uses the linear valve on the shift lever rod to engage the 6x6 when it is placed in low range

I am assuming your wipers and other dash functions work? They all work off the same air on the pressure protection side. This is assuming your pressure protection valve is opening. It only takes 65psi to operate. Your pressure protection side only opens and supplies air above 60psi in the wet tank

Ensure your air pressure off of the pressure protection valve is accurate first so to see that it is opening properly


Video or the single air line mod to bypass all that solenoid crap.

https://youtu.be/6vfG2pVDOIU

 

[SneakerZed]

Thank you for the info and video. I had watched that video the other day and I understand removing the solenoid but what I don't understand is the connections on the other end towards the front of the vehicle since it does not show it and it is only explained rather quickly. I will listen several times and try to figure out what is being referred too, find it in the manuals, and see if I can do the bypass.

 

[simp5782]

Thank you for the info and video. I had watched that video the other day and I understand removing the solenoid but what I don't understand is the connections on the other end towards the front of the vehicle since it does not show it and it is only explained rather quickly. I will listen several times and try to figure out what is being referred too, find it in the manuals, and see if I can do the bypass.

On the frame rail just in front of the drivers side transfer case mount there is a 4way block. You will block off 2 of them with plugs. On mine it was the top and the bottom one. It could have a different type of block as well. The other 2 fittings will simply pass thru it with air going to the firewall of the truck.

the line going to that block will be yellow.

 

[SneakerZed]

I am trying to find the line that was put into the front wheel drive and where it goes. I don't understand the terminology being used, what is a turtle valve connector, the only linear valve I can find mentioned in the manuals have to do with a winch. So i am at a loss.

 

[SneakerZed]

Thank you again for the vid but at this point it does not have the explanations that i need, in terminology I can understand and it does not show or explain the other end of the connections or where/how to make those connections. So i will simply continue troubleshoot the problems and fix what is broken and not bypass anything.

 

[simp5782]

The linear valve is the valve that is mounted on in front of the shift lever shaft. It looks like the same valve mounted on the parking brake arm as well.

It is just a 4 way block. Not a valve. A block with 4 fittings screwed into it.

https://youtu.be/6u_blhOAYDI

 

[SneakerZed]

AWESOME!!!!! Thank you very much, and thank you for your patience

 

[99nouns]

From my experience when these trucks get inspected at the depot they check for how much air it leaks during given time, and if it fails all the air lines has to be re inspected at all fittings, which is a nightmare, so sometimes if the mechanic gets too frustrated he starts plugging stuff with rubber pieces so he wont lose air, what you need to do is check and blow with your mouth if any of the lines p2p program shows has been clogged specially lines connected on and around the transfer case, there is one under the spare tire pain to get to, you might have to get in between the frame rails from under.

Sent from my LGMS659 using Tapatalk