JoeH

😛 nice to see someone local whos seen our trucks! The collision center is one of our numerous tenants, we own and rent out the 7 acres it's on.

Welcome to bmt!

Goes out nearly every day during the concrete season. Had roughly 350k miles when my dad bought it in 1986, we have put another 200k trolling around in our 15 mile delivery radius. Last thing the engine needed was a piston and cylinder head when it dropped a valve seat 8 or 9 years ago. How's that for up time?

Rears are 44k, that's what S indicates in rd690s. St would be 38k rears, sx would be 55k rears. According to the below website, the 90 in 690 indicates a maxidyne engine? But I didn't know they still made maxidynes in 1999. Maxidynes we're usually 300hp I think. Someone more knowledgeable will probably chime in. The 6 in rd690s indicates a standard highway frame. Should be a double frame, that's what my 95 rd688s has. Watch out for rust separating and cracking the frame flanges, that's a $25,000 dealer replacement job. https://onlineuniversity.bloomfire.com/posts/2387484-mack-trucks-vin-decoder

Rofl. That van owner cracked me up. Just get off the street...

Lol. Some of the rammyest drivers I've encountered on the road have been Swift trucks.

Give a call.

Rob and 1965 are right, check fluid levels and ground connections. If you're low on fluids they'll overheat, giving you a code. Make sure battery cables are clean of any corrosion and are tight. Check air filter, make sure is clean and not restricting air flow. I had just got off a 12 hour overnight plowing snow, so I wasn't typing straight. Could be bad sensors, but also could be that sensors are trying to tell you there's problems. Regardless, you're a far cry from needing an engine rebuild.

Hopefully the problem is the sensors and not the wiring harness going bad. Vmac III book tells how to test the circuits to determine where the problem is, wiring or sensor. Sensors are easy to replace, that's where I'd start.

Don't need to. They'll become inactive faults, and the light will go off. Light only comes on for Active faults. Sensors tweak the voltage on the circuit, which the computer uses to determine what's going on. It throws a fault code when the voltage in a circuit goes outside the programmed voltage range. When voltage comes back into the proper range, the active fault is no longer present, so the light will turn off. Assuming there's no other active faults.

Go to your Mack dealer and order V-MAC III Service Manual #8-211 and ETECH Engine Service Manual #5-106 8-211 has all the blink codes, the procedure to get codes, and how to diagnose the code fault. 5-106 has all the mechanical information on the engine, including sensor locations. Great intro section in it to give you how the computer runs everything. If it were my truck, I'd use the books to go through and change all those sensors. 4-2 is possibly a faulty Fan Clutch Solenoid. You should have some fun with knocking out those codes, I'll bet that faulty exhaust temp sensor and the ambient air sensor is your boost problem. Failing sensors are telling the computer the EGT are hotter than they really are, and so the computer is cutting back on the throttle.

2-1 engine coolant temperature sensor 4-2 fan clutch output 2-5 front drive axle oil temperature sensor 2-6 rear drive axle oil temperature sensor 2-4 transmission oil temperature sensor 3-1 exhaust temperature sensor 1-4 ambient air temperature sensor

I haven't figured it out yet either, but I think you have to downsize the picture file size.

You'll love the air ride cab. Nice thing about the big oil pan and 3 filters is 25,000 mile oil change interval. What's hard on the cams is when a tappet lifter face breaks. Wipes the lobe off the cam pretty fast. We just had to replace one for that last year. Good thing we had a spare motor here, Mack can't get the cam anymore. Maybe PAI has them? I've only heard of PAI from guys here, never dealt with them.

You can always ask around here and see if someone has a Jake brake on a spare engine they'd part with. You need all the under valve cover parts including the risers, plus an offset tip turbine adapter/plus offset hose going from intercooler to tip turbine, plus clutch/throttle/dash switches.

Let us know how it turns out once you have it running.

My crane has a 237 straight piped with a heat shield, but you can't have it. No idea if it's factory, last time the truck was inspected was in the 80s or early 90s. Just does yard work now. The turbos qualify as muffling devices, or so my dad says, but all our road trucks have mufflers anyway. A steel shop could make you a heat shield, cut out whatever pattern you want on a plasma table and roll it. Send it out to be chromed. My older trucks all use a rubber strap at the back of the cab to hold the stack upright, don't know if that's stock or not. Look for one from a DM. They're supposed to have a muffler box down low with a straight stack coming out, with a heat shield on it. That's how our dm we just retired is set up.

You'd be surprised, I actually have a concrete customer with a dually wheelbarrow with a set of wheels across the legs, it scoots along pretty good with a weed eater engine. It just doesn't turn, you gotta pick it up to turn it.

The slip on one looks like the elevator arm on a hand crank R model window. My dealer (bergeys) is pretty good about looking up that kind of stuff, but the parts guys are always busy. Id hate to bug them over nickels and dimes.

How did bolts break? Did they pull out of the threads in the block? Did the bolt heads break off and leave the rest of the bolt in the block? I'd guess someone overtorqued the bolts and stretched them, thus weakening them. Maybe try grade 8 bolts. They get torqued to 42 ft lbs.

If you didn't have the hills id say it's be a waste on the maxidynes powerband, they make 90% torque from 1200rpms up. Extra gears are kind of a waste, you're pretty much always in your powerband. And the maxitorque trans has 3 countershafts to handle the torque, the Eaton only has 2. Do you have an engine brake on there? It'll make a huge difference on your stock setup, makes the tall gearing a breeze when you use the engine brake for shifting. I'd start by putting a Jake brake on before swapping transmissions. Not sure what the top gear ratio comparison is between the two transmissions, that'll tell you if you'll gain or lose top speed.

Looks like he's off the shoulder enough to pitch the center of gravity a bit more safely.

My 79 R686st leans the same way, I assume it's saggy springs or to compensate for crown in the road.

As a concrete truck driver, I can appreciate this thread. Let's see this kid balance this wheelbarrow with 300lbs of concrete in it.

Less rotation mass on direct drive I would guess with tall rear. Crank connected to input straight to output to the rears. On an overdrive power has to go through the gears. Before the output shaft. Both still have the deadweight of gears though, being constant mesh.