The Nitro

I will order a new valve and pull this one apart afterwards just to see how it works. Thanks for the tips.

I am working on getting my 2004 mack vision tipper ready for rego and I am hearing and seeing air leaking out of the boot on foot brake where it goes through firewall. Its leaking in the cabin side where pedal pushes on the valve. It leaks air when we press brake pedal lightly but seems to stop leaking if we push pedal hard. I can hear a feint leak from engine bay side when I lift little round rubber flap on brake valve but most of the air seems to leak into cab side of valve. it’s my first truck, Is this normal of not? I can’t hear any leaks there except when we push brake pedal. theres 8 ports on valve 4 up and 4 down theres a number on top of valve 5631 thanks

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. 😃

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! 😂

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 😅

If you click on the diff tag picture it might make it clearer. That file was a couple megabites.

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

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

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

Thanks Joey, I will ask seller to have a look for the 11gba

Hello, I’m about to buy a used mack 2004 tipper and seller says its engine has been replaced before he bought it. I’m trying to figure out if its the 460 hp motor or if its an etech or an acet or what it is? truck is a days drive away so i cant quickly look at engine. I was sent picture of engine numbers on rh side of block below oil filler. Can someone say if this is the actual engine number or if hes looking in wrong spot? I’m in Australia heres pic. Any help appreciated please guys.

I’m from Australia and looking at buying my first mack truck for the farm. Its plated 4/04 as a vision CX 688 RST. The Engine number doesnt match the compliance plate. compliance plate says engine number Ea7-470 3R0377 but number on engine says AE74706Z1049 Can anyone tell by the numbers what kind of engine this truck has? thanks

Hi guys, I’m looking at buying my first mack tipper truck here in Australia. Its a 2004 mack vision with 18speed rr and 470hp motor. I am 600km from where the truck is so asked the seller for some photos and if looks to be very clean and tidy for its age. But in one picture of the dash I am looking at some sort of warning on a screen that says warning this version of vp software is intended for use with step 10 ecu’s please update your ecu software to step 10. Press enter to continue with the currently installed ecu. I am stepping up from a 1980 model isuzu sbr 422 9 tonne gvm flat bed to this nice looking mack tipper. The old isuzu is the only truck I’ve owned so not familiar with any of the newer ecu type trucks. The seller said he bought the truck in about 2014 and he thinks that mack has put a new motor in the truck in 2007 under waranty. current owner is 71 years old mack lover and said hes put new cam and ceramic lifters in and a new turbo and rebuilt gearbox and diff a couple other non engine related repairs since he owned it. Its showing about 350,000 km so i asked if that means 1,350,000 but he said mack reset speedo when put new engine in but it had approx 400,000 on it at the time. the truck looks very nice but the warning screen has me wondering if this is a big deal or not. I will ask him about it tomorrow on phone. any ideas guys ? thanks Andy