The Heinz

That's the same story, cost is higher on PAI than OEM... The actuator number on the turboturbos site only crosses to the position sensor and not the VGT itself. Safe to say I doubt Mack ever offered it separately. The controller is also available in OEM warehouses. I'm sorry to hear that about your family situation. I'm no stranger to heartache caused by family illness, lost my dad last year, and my mom had a stroke almost two months ago. Prayers for a swift recovery on his part. If you go the whole turbo route, I'd recommend getting the turbo mount and drain gaskets. I don't have any pulling power at any dealers local to you, so I doubt mentioning me would help at all haha. Maybe if you ask kindly they'd be kind to you. I don't know if I can take an order over the phone here, we've had scammers try it enough that management doesn't like us taking cards over the phone; I'd love to help you out if I could!

I forgot to mention it, but PAI is actually more expensive than OEM?! PAI ETC-8246 is $3,722.65 at cost vs the OEM turbo at $3123.31 at cost. I rounded up the price to account for tax and whatever markup the dealer "graciously" applies. Wow. The OEM turbo is available in warehouses as well, any dealer could get next weekday but with a nasty freight charge.

Perfect, superseded turbo part number is 631GC5176EM10X, and the actuator kit I found online is compatible with with this turbo. Here's the link. I don't know how trustworthy this site is, nor do I know the quality of the part. The turbo itself is not cheap, dealer cost is around $4k... But Nextran in Kansas City, MO shows to have one in stock as of yesterday.

I'm digging a little more to see if it's possible, but so far it appears to be sold with the turbo... I'll update if I find anything different. EDIT: Found a possibility, I'll need a VIN to confirm fitment.

I don't have a lot of experience, but if you're checking the EUP wiring, I'd start at the EUP's themselves. They're on the right hand side of the engine with lines going into the heads above. They're in a high-heat area, so we've seen some wiring getting brittle before. Could also have issues with the EUP/injectors themselves, but you'll want others' opinions over mine for that. As for the VECU, the engine module should be on the RH side of the motor as well, below the heat shields that also cover the EUP's and forward of the air compressor. Here's a diagram from a 2000 RD:

9-5 is a compressor discharge temp sensor fault, 2-9 is combustion air temp sensor, 8-1 and 8-4 are injector faults for their respective cylinders, and 4-9 is your EGR valve code for being blocked most likely.

The truck in our shop didn't have the same complaints, but I feel like at least mentioning one repair we made could be related to your issues. The truck was showing faults for VTG Position Sensor code 4-5, Turbocharger Speed code 6-2, among others. I don't know if the VGT was sweeping correctly before or not, so I can't say if this truck had the same problem or not.

Here's some pics of the truck in our shop. The housing my sausage finger is pointing to is the VGT filter base. Filter is upside down underneath. EDIT: Feel like I need to clarify my finger doesn't look like this, my camera made it look worse than reality lol.

It was behind the oil filters on the driver's side of the engine block on the CXU in our shop. I can only imagine it would be the same for yours. It's a very shallow but wide filter. Looks like the below.

No problem, I try to help out when I can.

Here, I'll post the pictures of what Impact shows and try to explain a little to help out: This is looking at the truck from the front passenger side. The actual VGT is the turbo, which is OPTION 1. The filter in question is in OPTION B, which I'll show below. It goes to the driver's side of the engine. OPTION 15A is the filter FJH is talking about. It should be identical to the 2006 CXU we have in the shop I used to find this. Mack part number is 25502444, WIX cross is 49458. It's mounted on the engine right next to the oil filters. The afore mentioned truck in our shop has different issues, but me and the foreman noticed when the tech revved the engine after fixing a misfire the turbo made a nice little metal-on-metal noise for a split second, like the turbo isn't getting the proper oil quick enough. Fun stuff!

The original part number should be 37QR5140 according to PartsLinq's supersession chain. Searching that gave me some results. Dixie Truck Center in Lakefield, ON has a listing on truckpartsinventory.com, could maybe call them and see if that's an option. https://truckpartsinventory.com/part-details/85075935/used-1997-mack-rb688s-dash-ass-y-for-sale Northwest Truck in Alberta, Canada could potentially have it too, will need to call them to find out. https://parts.nwtruck.com/part/QR-37QR5140 Those are the best options I could find, even though getting parts from Canada is a royal pain, believe me...

Yea, that's my bad for not looking as closely, sorry. I couldn't find any other good crosses, don't know where to suggest you find the right ones either.

The part numbers don't cross, can only assume they're not interchangeable... Thanks for that link, could be handy in the future.

Same here. I imagine using any other turbo would need some aftermarket tuner to program it, which I have no idea on what to recommend. I don't think the turbo off an AI ASET will work, they have different manifolds and turbo mount gaskets, but I could be wrong.

I am not well versed in old truck parts, but I was able to find some different crosses other than the Euclid kit. Found this TRW brand kit K506B, the size according to mpparts.com is 1.250" x 7.88" I'll attach a screenshot to see if it appears what you're looking for.

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.