Answer to Mark Douglas regarding AWD problems:

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Mark Douglas

Ok... the hits keep on comm'n ;-) 

 

Now my front wheel drive seems pertinently engaged. Sometime yesterday afternoon, the engage switch doesn't seem to engage and disengage the aux diaphragm. Also I don't hear the action of the diaphragm from the brake-petal anymore :-( 

 

So the weak yellow light for the front-wheel drive does go "on" and "off" with the switch actuation. All the fuses look great (all gold-lead). The vacuum line into the diaphragm looks good (plus new diaphragm 4 weeks ago installed). Based on the wiring diagram, seems the switch on the control panel is working (however, I have not got a meter on it yet)... but since neither BOTH the brake-petal and switch seem to make a difference... could it be the solenoid (these are electro-mechanical and should have a good life... not sure).

 

ideas or trouble shooting suggestions?

 

Thanks in advance guys!

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Mike Fox What happens if you switch to low-gear?

Yesterday at 3:00am Â· Like

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Mark Douglas Thanks Mike Fox; however, isn't "low-gear"l a use-case where the there is no vacuum (i.e. front-wheel engaged)? I mean to say I need a condition where it's disengaged. I;m not sure how going into low will help diagnose. but I am open to it for sure Mr. Mike. Do tell

Yesterday at 3:04am Â· Like

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Mike Fox Sorry, I mis-read or read too fast. I thought you had problems ENGAGING your AWD. My bad. Low gear will NOT help you diagnose anything unless you have a multimeter on the solenoid valve. 

Yesterday at 3:07am Â· Like

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Mark Douglas I have a multimeter... I just have NO idea where the solenoid lives in this vehicle 

23 hours ago Â· Like

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Mark Douglas BTW: I am ashamed to say I am not sure how to engage the low-gears. I depressed the thumb-lever on the stick and went all the way over to the right... and went H and L... seem... only H works. uht-oh... seems like my low is not working; but, that could be another issue all together. Staying focused on the front-wheel drive... for disengage I am very open to your help.

23 hours ago Â· Like

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Mike Fox It's behind the passenger seat, in the passenger compartment (on the wall behind the flight crew seat).

23 hours ago via mobile Â· Like

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Mark Douglas up in the air? or below?

23 hours ago Â· Like

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Mike Fox Tip up the seat and you will see it above the heater.

23 hours ago via mobile Â· Like

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Mike Fox Still no workshop manual? 

23 hours ago via mobile Â· Like

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Mark Douglas is that a nice way to say: RTFM  he he. I do have a nice printed one.

23 hours ago Â· Like

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Mark Douglas so in the back cool. I'll take a look in a bit. thanks!

23 hours ago Â· Like

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Mike Fox NP bro! And yes, it was a RTFM you lazy yank!

23 hours ago via mobile Â· Like

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Mike Fox Let me know how it plays out for you.

23 hours ago via mobile Â· Like

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Mark Douglas I am a yank and proud; however, just a bit lazy 

23 hours ago Â· Unlike Â· 1

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Mark Douglas so the debug is: see if the solenoid is actuated with the switch "in" and "out"?

23 hours ago Â· Like

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Mike Fox Well, see if there is any voltage at the solenoid when engaging / disengaging the awd. If there is and it's 24 volts your solenoid is the culprit. If not, there's another problem (electrical) and you're on your own... 

23 hours ago via mobile Â· Like Â· 1

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Mark Douglas Thanks Mike Fox (helpful as always!)

23 hours ago Â· Like

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Mark Douglas BTW: are there any issues with being in awd when on the freeway? can this truck be driven with front wheel drive and going 55mph? any danger?

23 hours ago Â· Like

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Mike Fox NP! Good luck. Sorry I couldn't give you more precise instructions but I actually don't remember when the solenoid is actuated and not. Logic says it should be relaxed and therefore have no power when awd is engaged. Can't say for sure though. Too tired to think. 

23 hours ago via mobile Â· Like

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Mike Fox The danger is that you get tremendous stress in the chassi if your ties is even slightly different in circumference and that is one thing you can be sure of. You hear it as periodic "clonks" when driving on paved road with awd engaged. YOU SHOULD NOT USE AWD ON PAVED ROAD IF NOT SLIPPERY!!!

23 hours ago via mobile Â· Like

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Mike Fox â€ ... tires ARE...

23 hours ago via mobile Â· Like

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Mike Fox If you have to drive before your issue is sorted you should remove the front prop shaft.

23 hours ago via mobile Â· Like

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Mike Fox ... Alternatively bypass the solenoid so that you get vacuum to the clutch bell.

23 hours ago via mobile Â· Like

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Mike Fox Do you have vacuum? Does the diff locks work? Indicator light should indicate working vacuum actuation.

23 hours ago via mobile Â· Like