The Nitro Posted February 26, 2022 Share Posted February 26, 2022 (edited) Hi, I have a problem where I press the electric diff lock button on a 2004 mack vision bogie tipper and the light on switch doesnt come on and I can hear a heap of air coming out of the rear most diff breather. I’m guessing the diff lock button light is not coming on because the piston isn’t moving to press the switch in diff? the diff has a label which I will post picture of and another picture of the part I may need help removing to check it. Can someone explain what I need to do or tips to remove this contraption out of the housing please? thanks Edited February 26, 2022 by The Nitro Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted February 26, 2022 Share Posted February 26, 2022 I would think that the o-ring on the piston is broken, or possibly a cracked piston. So then the piston is not moving which wont engage the detent ball on the end of the switch, as you stated. I would just pull the small cover off and inspect it.. .............. I just looked at the picture again.. maybe pull the detent switch out first and turn the lock 'on'. I bet air comes out of the hole. I am wondering if the bolt next to the piston housing is actually a 'caging bolt'.. used to keep the shift fork from dropping out of place.. I don't remember how these diff lock's look inside, because I havent had one apart in a long time. However, sliding this rear end forward is not that big of a deal, in the case that you had too. I just looked again at the picture... I wonder if behind that small bolt is a counter bore with smaller threads, where you would screw a longer smaller diameter bolt, like an 8mmX1.25 metric bolt and it cages the shift fork.. If I remember correctly, to remove the piston housing, you would use a pipe wrench and unscrew it. Maybe get a close-up pic of the data plate. I think its and Eaton 405, I may have a service manual on this model, of course, I also expect a few guys to help you more directly than I can.. Jojo Quote Link to comment Share on other sites More sharing options...
The Nitro Posted February 26, 2022 Author Share Posted February 26, 2022 The diff is a meritor RR 23 160 Australian version. thanks. I’m not sure what that bolt does. Only bought truck a few days ago and it’s my first truck so dont really know much about it Quote Link to comment Share on other sites More sharing options...
The Nitro Posted February 26, 2022 Author Share Posted February 26, 2022 Theres 2 buttons for locking diffs. One electric which sends air to both diffs with the same looking pistons screw in thing that we can see in my pics and then theres an air type switch with hoses that only sends air to front diff Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted February 26, 2022 Share Posted February 26, 2022 ok. I understand.. I guess I threw out a few old ideas I had. Yes Meritor is right.. I know I said eaton, but I looked at the picture again, I know that I do not have a Meritor rear end book.. Here in the last month, I bought 3 Mack books from E-bay.. There is a bunch of guys on here from youre part of the world, who are very smart, maybe one of them is familiar with the Austrailian version.. jojo Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted February 26, 2022 Share Posted February 26, 2022 The front diff. system may just be a power divider lock. It would be going into the input housing.. Quote Link to comment Share on other sites More sharing options...
The Nitro Posted February 26, 2022 Author Share Posted February 26, 2022 If you click on the diff tag picture it might make it clearer. That file was a couple megabites. Quote Link to comment Share on other sites More sharing options...
The Nitro Posted February 26, 2022 Author Share Posted February 26, 2022 I didnt want to undo anything yet in case that bolt you mentioned needs something done with it first etc. id hate to have something fall inside because I done it wrong 😅 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted February 26, 2022 Share Posted February 26, 2022 Yes sir I understand.. I guess, for me, I would go for it because I have had many of these rears apart, just not one with diff locks in a long time. but the inner workings are pretty standard.. I dont feel like im helping much... sorry.... jojo Quote Link to comment Share on other sites More sharing options...
The Nitro Posted February 26, 2022 Author Share Posted February 26, 2022 I appreciate your input mate, I’ve enjoyed looking at your posts on this website. Being a new rookie mack trucker now I’ve got lots to learn. I’ve done a couple crownwheel and pinion swaps on my 4x4 toyota with dial guages etc so know a little bit but have never fiddled with trucks..... yet! 😂 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted February 26, 2022 Share Posted February 26, 2022 very good.. I need to go back to bed.. I couldnt sleep so i came here... now im sleepy again. I will check in later. jojo Quote Link to comment Share on other sites More sharing options...
Mark T Posted February 26, 2022 Share Posted February 26, 2022 (edited) There should be two switches. One is the interaxle lockout (power divider) and the other ( in this case ) is for what's often referred to as "full lockers" Probably what ever form of diaphragm ( I think is O rings in these ) is in there (your picture) is leaky. Used to be if you needed to cage them up, you removed the fitting and used a long bolt to engage the sliding clutch into the carrier. 🤔 I don't think you'll need to do that to make this repair. Usually it can't go anywhere with the axle in it. Edited February 26, 2022 by Mark T more information Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted February 26, 2022 Share Posted February 26, 2022 Thanks Mark. I was trying to help him with this, and wasnt sure if the small bolt had a small set of threads inside to cage the fork, like the older Eatons did for the power divider.. I think the leak is an o-ring and/or cracked piston.. Jojo Quote Link to comment Share on other sites More sharing options...
Mark T Posted February 26, 2022 Share Posted February 26, 2022 I'm pretty sure they have O rings and that cover with the fitting screws off... and a piston with an O ring. That bolt in the picture I believe is the cage bolt just screwed in there for when you might need it to lock the sliding clutch into the case in the event you need to remove the axle. You lock it in, cage it then take the axle out (like for towing) Then if I remember right they're disengaged with a spring in there ??? But anyway, seems he has a leaky something (?) under that cover. Quote Link to comment Share on other sites More sharing options...
Popular Post The Nitro Posted February 27, 2022 Author Popular Post Share Posted February 27, 2022 I removed air line and got a pipe wrench with a bit of pipe over handle 5 ft long and undone the round screw in part which turns out is the piston barrel. Barrel was full of rust and piston was in good shape and it had a double lip type seal clipped on outer perimeter of piston. Half an hr with sandpaper in barrel and a smear of grease had the piston back in, barrel screwed back on with a bit of sealant on thread. Hooked air line back up and pressed the button in cab to test it. Couldn’t hear any air coming out breather but the red light on button didn’t come on either..... Unscrewed the diff lock sensor/ light switch from diff and looking in through hole I verified the piston is actually moving and all looked good. Done continuinity test on switch/ sensor and Its open circuit but has continuinity when pushing on the plunger so that looks ok. Ran a jumper wire across harness plug where it clips to sensor and still no dash light. Hmmmm. Traced harness along chassis and found another plug farther up. Disconnected it there and put jumper wire across pins and diff lock light in cab came on!! Found rotted internal wire on the diff lock harnes extension on not only the rear diff but also on the front diff as well. Cut the bad bit of wires out and soldered in new wires. Put it back together and Yee Haa, Both the diff lock button and the cross locks buttons working great. Reversed truck up a muddy incline to test and both buttons and diffs work as intended again. Thanks guys. she’s fixed. 😃 2 1 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted February 27, 2022 Share Posted February 27, 2022 Awesome... Thank you for posting the process to fix it.. I'm glad you "went for it" Jojo Quote Link to comment Share on other sites More sharing options...
70mackMB Posted February 27, 2022 Share Posted February 27, 2022 As Mowerman has said before, They ask for advice but never say how things turned out! The Nitro, Thanks for a detailed answer to what and how the problem was solved. And now we know the rest of the story. .....Hippy 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted February 27, 2022 Share Posted February 27, 2022 Good Dayyy .... Nice reference Hippy.. jojo Quote Link to comment Share on other sites More sharing options...
fjh Posted February 27, 2022 Share Posted February 27, 2022 3 hours ago, Joey Mack said: Awesome... Thank you for posting the process to fix it.. I'm glad you "went for it" Jojo YUP TOTALLY AGREE ! please post your FIXES GUYS! This helps others and everybody learns ! That is what its all about! Quote Link to comment Share on other sites More sharing options...
doubleclutchinweasel Posted March 1, 2022 Share Posted March 1, 2022 Great job, Mate! Quote "Eagles may soar, but weasels don't get sucked into jet engines." Link to comment Share on other sites More sharing options...
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