5 Ton M931A2 CTIS LOUD Whistle sound

[JeffRH]

I've had my 5 Ton for about 5 years and have had NO CTIS problems. Until now. My truck sat for about 4 months and when I start it I get a very LOUD whistle which sounds like it is coming from the rear. I'm not familiar with repairing the CTIS so I have investigated the issue in manuals and forum posts and it sounds like it could be a rear axle seal. Since the sound was coming from the back, I thought maybe the front would air up, but all tires are at about 20 pounds and not changing. The Highway light continues to blink.

Problem is I do not have the tools to repair something like this. I guess I've been lucky for 5 years and have had no issues with anything on my truck.

Any idea about what is happening and who can repair something like this in The Woodlands/Spring, Texas area, which is about 25 miles North of Houston.

Here is a short video I posted on youtube of the whistle sound.

https://youtu.be/aY9VA2fpslc


Thanks
Jeff

 

[simp5782]

Take soapy water and spray your fittings and everywhere on the axle to see where the air is leaking from. Could be a simple fix. Or at least you know where the issue could be rather than some truck repair place jerking you around.

Sent from my SM-G860P using Tapatalk

 

[Suprman]

Bad hub seal. Fill air pressure diluted by hub seal leak so wheel valves see low pressure and are tricked into dumping. Unplug controller till you do hub seals.

 

[JeffRH]

Thanks for your replies,

I did disconnect the ECU and filled the tires manually to 50lbs. I reconnected the ECU and started the truck and as soon as the ECU sent air to check pressure the loud whistle started again. So I disconnected the ECU for now.

Any clues on where to even start to find someone to repair the hub seal? I'm just north of Houston so there are some commercial truck shops around here, but I'm thinking this might be outside their abilities. There are even more truck tire shops but again probably not their area of expertise.

Thanks for any suggestions.

Jeff

 

[Jbulach]

Have you narrowed it down to which axle and side?
I would avoid a tire shop, but any truck shop could handle it, problem is they might not be able to give you an estimate up front.

 

[Steelreaper80]

My M925A2 just started doing this exact thing this week. What parts do we need to order to fix it? Can the truck be driven with the CTIS disabled or does it need immediate attention?