M923A2 - Stalls in Reverse - high range

[TechnoWeenie]

So, picked up my truck at auction... Got a good deal knowing it was a gamble... and .... here.... we... go...!

So, couple small issues.

Air leaks down pretty quick. I will have to put shop air on it and spray all fittings with soapy water. Pretty easy way to diagnose.

Also sounds like there might be an exhaust leak. There's a rhythmic ticking that sounds like air escaping that corresponds to RPM. You can hear it in the cab very distinctly.. They also bypassed/removed CTIS, so that's gonna be interesting... Also, ABS light is on solid so that has to be investigated too.

The other issue is a head scratcher.

Put transfer case in neutral before towing... Towed with another 5 ton, air lines hooked up and all.

Got it back, went to go back it up after dropping it in high range, and it stalled... Tried to put it back in N and then back into high range thinking it didn't go into gear, and it felt like it was binding, like air brakes were locked... like it wanted to go but couldn't. Put it in low range, drove forward no issue. Backed it up in low range (yeah, yeah, save it) for about 5 feet with almost no throttle, and also, no issue... Put it back in high range.... and... dies in reverse....put it back in low range and again, no issue reversing...

I recall reading something about the transfer case switch sticking, and I do recall hearing the solenoid actuating when I had soldier B hitting the switch, and could hear air venting....but I'm not finding much in the TM or here that goes into much detail, and my memory is not that great anymore.

Thoughts?


I do plan on rotating the front axle engagement switch that's actuated by the collar on the transfer case rod, to disable automatically engaging the front axle in low range.


Just trying to figure out the stalling issue.

Former agency said truck was 'unreliable' and they 'think it's the fuel pump' but didn't wanna spend any time/money on anything. I'm pretty much starting from scratch on diagnostics.

Gauges show 31K miles and ~250 hours... if it's accurate is anyone's guess. But agency had it for a bit before surplusing it, so it worked for a while and the issue is relatively new.

 

[TechnoWeenie]

Anyone?

 

[Valley Rock]

Hey nice looking truck, looks uber clean .
So it drives fine forward in high ?
If so personally I would start beating it down the road and getting heat in the trans and making things come back to life, I find these things develops issues sitting around, I know mine has .

Some things will fix themselves others will show themselves, I seem to remember mine doing what your describing more than once, I drove it around and it fixed itself .

Sorry I dont have a more technical answer, just some experience .

So you can remove the front axle auto engage by eliminating that washer on the linkage ?

 

[TechnoWeenie]

Hey nice looking truck, looks uber clean .
So it drives fine forward in high ?
If so personally I would start beating it down the road and getting heat in the trans and making things come back to life, I find these things develops issues sitting around, I know mine has .

Some things will fix themselves others will show themselves, I seem to remember mine doing what your describing more than once, I drove it around and it fixed itself .

Sorry I dont have a more technical answer, just some experience .

So you can remove the front axle auto engage by eliminating that washer on the linkage ?

I haven't gotten back around to messing with it. Transfer case seems super stiff, even aired down.. so I sprayed all the linkages and am letting it sit. Next step might be to remove the inspection cover and take a peek inside.

I'm gonna be testing the switch as well to see if it's stuck in.


The big washer actuates an air valve that directs air to lock in the front axle. You can either remove the ring, or, what I'm gonna do, is just loosen the hex screw that holds the actuator lever to the shaft and rotate it 90* so it doesn't make contact, so it's easily put back to factory if need be.

 

[TechnoWeenie]

Switch was indeed stuck. I shot it with a ton of contact cleaner and actuated it a bit. Seems to be working properly now. Not ready to take it out on the open road but 10' forward and reverse seems to have no issues.


--My filters are starting to show up.. Good lord... I bought a Baldwin B96.... I feel like I can fit my head in that oil filter.... Almost 5" wide and 12" tall...
The Baldwin B205 is a little shorter version of the B96 and technically the correct oil filter, and I got a 6 pack of those.. those are 5" wide and 8" tall. Should be fine just running the B205, but I'll probably run the B96 with the first oil change, with full synthetic... Should be able to handle a little more junk being 25% bigger w/more filter media.