2014pinnacle Posted April 24 Share Posted April 24 Hi guys I have 2016 mack pinnacle with Mack axles. This morning while doing my circle check I notice my axle lock is stuck on theirs a light on the that says fr axle lock when I hit the axle lock switch nothing happens, when I start driving a message comes up on the display saying inter axle. All the wiring is attached to both axle housings I don’t see anything broken or rotted off what should I be looking for? How do the axle locks and inter axle work on Mack axles. Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted April 24 Share Posted April 24 Do you have a row of celenoid s on the frame rail behind the cab? They are small. And they are piggy backed. They control suspension, fifth wheel, power divider, or whatever else. That i where the air is delivered to the component. Quote Link to comment Share on other sites More sharing options...
2014pinnacle Posted April 24 Author Share Posted April 24 Do they look like a bunch of little black cubes? Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted April 24 Share Posted April 24 Yes Quote Link to comment Share on other sites More sharing options...
The Heinz Posted April 24 Share Posted April 24 The actual diff lock switch can be bad too, we've seen this a couple of times. At least the company's drivers said they didn't leave the diff lock on during interstate driving. Quote Link to comment Share on other sites More sharing options...
fjh Posted April 24 Share Posted April 24 If they are Meritor diffs the switch may be faulty on the diff! The axles may not be locked but the switch is saying they are! Quote Link to comment Share on other sites More sharing options...
2014pinnacle Posted April 24 Author Share Posted April 24 They’re Mack axles it’s strange that it says they’re engaged I’m an owner operator no one drives this truck but me and I don’t ever use them. Quote Link to comment Share on other sites More sharing options...
Geoff Weeks Posted April 24 Share Posted April 24 You really need to ascertain if the diff lock's are on or just the light. Side to side locks will be evident if you try to make a sharp turn, PDL (interaxle) will not be quite as evident. None the less I think it is highly unlikely the locks are on and you don't know it. Much more likely a switch or wire is the problem. You can take the air lines off the actuators and throw the switch one way and then the other, you should get air in one position and not in the other. Truck may need to be in "running down the road" (brakes released) condition for this test, so wheels blocked so it can't move. In the years I worked on stuff they could be air apply or air to release (reverse air) but I think everything today is air apply. (IHC and some Dana axles could have reverse air) I don't know about Mack axles. You will likely need wiring diagrams to track down how the light is lit and which wires to look at. Running around in the locked position will cause excessive tire wear and long term will damage the diff's so get to the bottom of it. 1 Quote Link to comment Share on other sites More sharing options...
The Heinz Posted April 24 Share Posted April 24 14 minutes ago, fjh said: If they are Meritor diffs the switch may be faulty on the diff! The axles may not be locked but the switch is saying they are! Now that you mention it, yeah I was half-wrong. We see the faulty diff lock switch on Meritors constantly. Customer lost a few diffs to it too, course that could have been driver error masked for warranty's sake, but I digress. We have seen a couple of diff lock switches faulting on Mack rears, but nowhere near as often (or as violent) as the Meritors. Could be that or wiring issue somewhere, unfortunately all I can do is help you guess! Quote Link to comment Share on other sites More sharing options...
Mark T Posted April 24 Share Posted April 24 12 hours ago, Joey Mack said: Do you have a row of celenoid s on the frame rail behind the cab? They are small. And they are piggy backed. They control suspension, fifth wheel, power divider, or whatever else. That i where the air is delivered to the component. I believe that arrangement is called "modular" (that valve that you just keep adding to for more components to control withone air source) 👨🎓 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted April 24 Share Posted April 24 yep.. Quote Link to comment Share on other sites More sharing options...
2014pinnacle Posted April 25 Author Share Posted April 25 Ok I just got my truck back it turned out to be a combination of problems changed the sensor on both diffs plus broken wires. Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted April 25 Share Posted April 25 what sensors? ABS ?? Quote Link to comment Share on other sites More sharing options...
JoeH Posted April 25 Share Posted April 25 Probably the sensors on the diff lock mechanisms. 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.