The Heinz

Wish I saw this while at work, I won't be back in until next week! Thankfully there's been some very helpful replies already. I'll check this out next week just for kicks.

Here's a simple diagram of the CAC system on a similar truck. Like Joey said, the actual charge air cooler is in front of the radiator. You can look up Youtube videos on how to pressure test a CAC system if you need.

Thanks for that info, might help me in the future.

I was able to get a hold of a spec sheet that had parts going up to 80 PSI, nothing on a 100 PSI version. The 80 PSI option supersedes to 25501698, limited availability in Mack warehouses, but obtainable. No PAI cross that I could find.

I checked to see if we had one, but it's been a really long time since our inventory saw one of these. None of our other stores showed any either, and our "best" electrical tech had nothing helpful to give either. This'll be outside of what I can help with unfortunately...

I know which valve you're talking about, but I can't find the part number for the 100 psi version. All the ones I can find are the 54 +/-7 PSI or lower. I'll see if I find anything, but hopefully someone else can chime in as well.

Gotcha, that's quite a ways from me! Glad you were able to find what you're looking for. Hope you stick around so we can see the end results too!

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!

You could contact DEX Heavy Duty Parts, they tend to have used engines for sale, just don't accidentally buy a core engine unless you want to overhaul it! A shame someone stole the valve covers and head, or else you could piece the engine back together and go from there. Sorry people these days have no shame in putting others in a bind. It isn't my money being spent, but it would be great to see your dad's old truck making you money. If you go the engine swap route, I'd try to find an E7 ETECH, pre ASET, which should fit right in (Experts, please refute my claim if need be!). Though like Bob said, the truck was parked for a reason, and an Allison transmission could be why. They can be a bit expensive to fix, but they certainly are fixable. If you wind up needing any parts and happen to not be too far from me in NC, I'd be happy to help locate smaller engine parts like the turbo, EUP's, etc. I just won't be the best help with used engines, I don't have many resources for that.

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.

This is why Colt's Single Action Army was called "The Great Equalizer." You can be up against a super jacked dude and his pitbull, but just having a firearm instantly puts the ball in your court. People and dogs don't do well after taking a couple 9mm rounds to the body. It's sickening and ridiculous that these people get protected by the bureaucratic system that is supposed to protect us.

Yeah, it's usually cheaper to outright replace than to repair now. It used to be similar with engines, but we've seen a couple of fleets in our area request in-frames on ETECH or ASET engines, which to my surprise actually ended up being cheaper for them. As for transmissions (that aren't mDrives), we never tear them down with the exception of a few Allisons and one Eaton. Being a dealer, it very much is a Parts Cannon methodology: metal in trans fluid? Quote a reman and be on your merry way. It's always a parts changing job though!

I think they went away from the shim setup, but I could be mistaken, and they certainly fixed the cup issue after the early models of the engine; doesn't mean cups and injectors are flawless, we see a lot of failures there still! We have had quite a few gear train failures in MP7's now that you make me think of it. The MP10 honestly sold really poorly, at least in our area. I've only seen one truck to my knowledge with that engine.

You're absolutely welcome. The DO cover their own workmanship, but I feel like they'll do fine with a manual transmission; all of our failures were with automatics. They've done a good job with the couple of diffs we've used.

They're not lying, no dealers in the system (both US and Canada) show any, and PAI doesn't even list it anymore. I checked all my old part sources and found nothing. Maybe someone here can help, but I don't think I can...

MP7 usually has fewer rocker shaft bolts than an MP8 from what I've seen, along with a more complicated EGR setup. The 11 liter also has a weird timing gear setup with one idler gear bolt being a flywheel housing bolt, which is a bigger pain in the rear from what techs tell me. As far as reliability goes, I feel I see more MP7's have major repairs than MP8's, but that very well could be a sample size issue. My last job at a fleet had nothing but 13 liters and we had few major engine issues, while a competitor had 11 liters and were constantly towing them to the dealer. I personally would recommend the MP8, but my opinion only comes from observation as a parts guy. EDIT: I asked one of our best techs about the difference and the MP7 was designed for heavy duty vocational work. We see them a lot in trash trucks, cement mixers, dump trucks, etc. It makes since to me now that I know, the fewer rocker shaft bolts are massive compared to the 12 small ones on the 13 liter. I guess it would depend on what your trucks are going to be used for. If you've had good luck with the MP8's, I'd probably stick with that combo. Just make sure to change the air dryer cartridge reliably and to keep your eyes and ears out for air leaks in the bellhousing. I've also been told keeping the RPM's lower keeps the mDrive from killing itself as much, but I don't think there's really much that can be done to avoid it.

We've had some deleted trucks come in, but our service team (of course) didn't realize they were deleted until we looked into them. We didn't do any engine work except one that tricked them (us): the guy's tune killed the ECM and we diagnosed it as such. We didn't replace but instead told him where he could find an aftermarket one and had him buy it. One of our techs installed it for cash on the side after hours if I remember right. I despise emissions systems and frequently talk about the delete process with pickup friends, even deleted the EGR on a 2011 6.7 Cummins, but I can't approve of doing it to a semi. I'd love to see an MP8 running as efficiently as possible to bring back some of the reliability Mack used to be known for, but the amount of trouble you get in for getting caught is horrible. Local guys have declared bankruptcy because of it.

I tried breaking down your old part number and the new, along with a 1997 and a 1996 truck I had a VIN for, and couldn't make a number match. The 1996 and 1997 match with each other, but neither yours or the one online. If you shoot me at least the last 6 of your VIN, I may be able to dig a little deeper with other part numbers. I'm a parts guy for a dealership, I have no reason to do anything malicious with anyone's VIN if that helps ease any doubts.

It's ridiculous how much they cost, I know... If you ever wind up needing another one, I could very well ship you an Automann cross for much, much cheaper.

The guy that posted the original improved ASET upgrade mentioned getting one from a local scrapyard, given getting a brand new one from a dealer like me (and discounting the three pieces heavily) costs around $1k + shipping, I'd vote for the scrapyard route to save money. He also mentioned not needing to replace the cam, which seems logical; to my knowledge the internal EGR the cam performs is similar to the Cummins 24 valve common rail engines, which were extremely reliable. Someone correct me if I'm wrong though.

Just a parts guy, but the oring for the compressor side could be pinched. We also see the CAC hot side pipe going into the turbo fail all the time, we usually replace the boots and clamps with spring loaded types. I only saw this once, but the CAC cold pipe going into the throttle valve had cracked somehow and was causing a decent boost leak.

The customer I mentioned previously never actually went through with the diff swap, it just cost too much money and downtime just to get his RPM's and top highway speed to where he preferred. It's definitely doable especially if you do it yourself or have someone cheaper than a Mack dealer do it. I don't know which you'd rather do/have done: the "ASET delete" or the regear/diff swap. In my opinion, which doesn't hold much weight mind you, giving your engine the ability to breath would probably be the first thing I'd do if I were in your shoes. What I did to get the part numbers for the diffs was create an eService case. They usually suck, but specification questions like this do well with them. I have to have the entire VIN to start one if you wanted to go that route. I unfortunately don't have old books or knowledge on diff part numbers and their gear ratios!

The sensor 22564822 has an o-ring on it, but your expansion tank could have a crack too if it's old/wore out. PAI has no stock, but the OEM is readily available right now. If your local dealer has Automann access, they are much cheaper. Automann expansion tanks are also really good quality, it's about all we use thanks to availability.

Weller Truck Parts is an option for reman transmissions, just be warned that we've had a lot of issues with their transmissions specifically. They were mDrive junk, so I'd hope they could properly reman a manual. I'll dig around a little as I go today to see if I can find anything, can't promise much as we're understaffed, overworked, and underpaid.

We have a customer with a somewhat new to them 2000 RD690 that wanted similar, so I was told to get a quote for different ratio diffs. We ARE a dealership after all, much cheaper in the long run to swap diffs thanks to labor rates. I'd assume you could find some diffs on a wrecked truck for cheap and clean them up before install as a money/time saver.