JoeH

I'm sorry to hear about your dad's diagnosis. Sometimes life hits hard and all at once.

Haven't heard from you in a bit, how are you making out?

I'd expect there's enough room between the differential and the axle tubes that the bits of axle would fall into the oil, but it's been a very long time since I've had a differential out of one of these.

My one brother managed to break an axle on our dm686SX!!! Those shafts are thick!! He was starting out on a hill, and decided he would use the parking brake to hold the truck while he got the clutch ready. Only he misjudged, the parking brake takes about 5 seconds to release on ths truck. He went all in on trying to go and.... Roadside repair.

Not sure how you're gonna get the splined piece out of the differential without pulling it... That's a pain.

Depends where it broke. Out at the hub or in at the differential? If it broke by the hub you should be fine to pull the pieces and shove a new axle in. Note the differential sits off to the right on Camelback suspension so the axle shafts are different lengths left vs right. Also the spline count and axle thickness can vary depending on your specs, so I'd just go to the dealer for one most likely. My dad used to score the axleshafts a little out by the hub. Then my older brothers moved on to other careers and now we don't have to score our axles anymore.

2002 has the Left Side Redesign, (started in 2001) the EECU is on the intake manifold on driver side of engine. VECU is on the passenger seat kick panel, it's common for the windshield seal to fail on R models and let water in to cause VECU issues. How are your batteries? What does the voltage do when you crank? EECU shuts off at 9.5 volts, so weak/failing batteries will result in a crank/no start situation. What blink codes do you have? Key on, cruise control off, press the set/decel cruise rocker down. Hold til lightning bolt blinks, then count the 2 digit code it blinks to you. Repeat set/decel request until codes start repeating themselves. Example code: 9-5. Share the codes here and we can point you in the right direction.

Fortunately there's enough of these engines running in my area that the parts guys at my dealer rarely have a problem. If they do they'll just email you the parts diagram to help pinpoint what you're asking for.

https://www.ebay.com/itm/235504211686?chn=ps&mkevt=1&mkcid=28 And here's the part number you seem to be looking for.

https://www.heavydutypros.com/mack-left-hand-axle-bracket-12qk43p2.aspx?utm_medium=paid&utm_keyword=&utm_source=google&utm_campaign=16494479656&utm_network=x&utm_placement=&utm_source=&utm_prodid=170860&gad_source=1&gclid=Cj0KCQjw_-GxBhC1ARIsADGgDjv60Be6aAlc9Gqgq6tJ8RfAmGjeqoPiwLY7E73_1G4R7C3n1IuWQ3saAgOvEALw_wcB Mack Axle Stop. Part number doesn't quite match yours, there's a front/back/left/right.

Mid 1970's til they discontinued the R model in ~2001. If the DM continues passed 2001 then they used the dash til the end of the DM.

I know my Mack dealer just got a new parts computer system. The new system only shows current part numbers, it doesn't show obsolete numbers. They have to go through three more steps to look up what obsolete numbers transfer to. Or some dumb excess of work. I wonder if that's why they're telling you you have to buy a full set of lifters or pushrods, they're working with an awful system and can't figure out how to pick out the part number for just one rod or lifter.

You have to order a full set?? Can't order 1 or 2??

An ENDT"B" engine I think would have Mack's Dynatard camshaft. Not sure how the Dynatard worked.

Yea you can run it without engine brake. Where did you get the cam?? I'm a little perplexed that you bent/destroyed a pushrod and wiped a lobe. Be careful adjusting the valves, they have to be done "by the book"! One cylinder at a time. A colored marker on the damper wheel is a big help to see the timing marks and which cylinder numbers you're at...

Number sounds legit. Try it at your local Mack dealer or pull one at a junkyard.

That's a sharp looking engine. I love the colors, just hate the association to MP engines.

Bump

I'd be shocked if a new cam is available, last time we tried getting one for our 1980 DM686SX they weren't available. 5-6 years ago on that one.

Parts engine would be a good investment for this job. You probably have a broken carbide face on the lifter tappet that wiped the lobe off. Common failure. Sounds weird to me that they can't order a single pushrod. Last cam we did we stole from our parts engine, stole cam and one lifter. No need to replace all of the budget doesn't allow. Lifters need to be held up with magnets taped to wooden dowels in the pushrod holes, to keep them up while the old cam.comes out and new one goes in. I think there's a company "Berry Cams" somewhere in the country that can weld new lobe on your old cam, but I have no experience with them. You'll be dropping the oil pan and looking for bits in there, you'll probably find a partial disc from the carbide face. Front engine mount is the timing cover so you'll need to pull oil pan, block the engine up on the block skirt before you can pull the timing cover. Good time to plastigage the crank bearings just to be sure you aren't due for new ones.

If you install the wrong type of switch in the wrong location then you can get a goofy result, like you're seeing.

I believe there's 2 brake light switches on the truck. One is a positive pressure switch on the treadle valve or near it. This senses when your foot hits the brake your lights come on. The other is an "off with pressure" switch, should be mounted on the parking brake valve. This senses when you set the parking brake your lights come on, when you pressurize your brake release circuit it turns off. But it should go off with key.

Other than that they're great engines. We have a 1979 engine still in daily service. It's had a couple camshafts in its life, but we have the donor engines to keep it going.

Ditto on pics. VIN would tell us a lot as well about which HP rating the engine has. A 285-300 HP usually got paired with a 2 stick 6 speed, whereas the 237 HP usually got paired with a single stick 5 speed. Unfamiliar with cruiseliners, so idk what transmission shifting arrangements they had. The engines aren't entirely bulletproof, I assume this truck will have 2 valves per cylinder, not sure if the 4v per cylinders were out in 1980. Weak point on these engines are the lifter tappets on the camshaft. The lifters use a flat carbide disc that rides on the cam, and these carbide faces can crack, a piece falls off and the sharp remaining edges cut the lobe right off the camshaft. I think there's a company "Berry Cams" somewhere in the country that can weld a new lobe on there, but I know the cam is no longer available through Mack, so you're on your own to repair/find donor cam and tappets.

https://www.paiindustries.com/ Here's one more resource for you, if you make an account on this website you can access tons of parts diagrams and part numbers for your truck. Can't buy parts through their website but you can take part numbers and get them from one of their dealers.