JoeH

I know what you mean, these old dogs are great. We have a 79 r686st that we've about worn out, and a 1980 or 81 dm686sx that's been relegated to yard duty. A little mechanical know how and these trucks will last a long time. Having several of the same trucks pays tremendously with spare parts and know how on repairs.

@Joey Mack is the resident expert here on ETECHs and AI/AC rebuildING. Where are you located?

I'm sorry you took the differential out of the truck unnecessarily, that's a chore and a half. Taking the body off too is a other chore and a half. Last one we did we jacked the front axle waaaay up, and pulled the whole axle housing out from underneath the truck. Then did same to the front. Our truck bodies aren't easy to remove, and the truck ate a bearing which busted teeth off some gears, so we decided to swap differentials to get a better top speed than 48mph...

Top wasn't way low, top was fine. You only check the lower axle housing plug when checking oil level.

It splashes UP! Then excess drains down.

It's all connected. Oil is flung up top by the gears down below. So oil is "circulated". There is no problem on your axle other than a wheel seal. Fix the bad wheel seal, then find a way to tilt the axle housing towards the replaced seal so that oil from the pumpkin floods the wheel bearings. Top up the pumpkin and you're done, good to go.

Oil is splashed up from below into the top housing... As Joey said, on initial fill you hit the top housing and then bottom, but after that you only check the plug on the back of the axle housing. Oil should be to the bottom of the hole. You keep putting oil into the top, and it keeps draining that oil to the bottom because its not low up top.

Not sure why it seems to have more space under the hood than most other R models. The hood doesn't look any longer. Radiator tank is strange to me; my 1979 has spray foam on the firewall, maybe that's the difference in appearance if space?...

And the VIN starts with the truck's year, 19"79".

RS600 Glider kit. Can't give it a "686S" or "690S" designation with no axles or engine! I figure it's probably the 807th glider kit they sold?

Only logical reason not to use our own energy sources would be a long term strategy to burn up everyone else's energy first so we're the last ones with energy reserves. But I have no clue how far out that plan would have to be thinking. 100 years? 500 years? By then we'll be drilling for oil on other planets, if there is any. Can't have oil with no carbon...

Someone's being rummaging around in the past.... 🤣

When the first code is done flashing hit it again to request the next stored code. Don't recall if this works if the lightning bolt isn't lit, displaying there's an active code.

Being a Vmac III, with cruise control off you should be able to hold the set/Decel button for a few seconds to trigger the lightning bolt to flash out a 2 digit code. That 2 digit code would tell us what the problem is.

Read this thread.

Sounds like you're working on a VMAC II system. Specifics are outside my wheelhouse. It sounds like it shuts off as soon as you let go of the key. My 12v Cummins uses a dual electric solenoid to stay in the "run" position. One strong solenoid pulls the kill lever into "Run", and a second solenoid holds it in "Run" while the first solenoid turns off. Not sure what this Mack uses. Other idea I have is faulty ignition switch. Ignition power makes contact when you crank it, but as soon as you get off the crank position power drops out for whatever electronics the injection system needs to run. I'd probably start with checking the ignition switch, then move to the shutoff solenoid.

If anyone has trouble getting their dealer to find the flash drive, here is a screenshot i took of the item description and SKU# from the Mack eMedia website. Works fine on newer web browsers than what the description says.

The way I describe our "new" truck is " You hit D for Dumb and you're driving!" Someone else explained it as "you hit D and Mr Allison drives the truck for you."

Go cut it out of a junkyard?...

Let us know if this one pumps oil too....

Id take Allison Dealers advice. My understanding of autos, as it shifts out of one gear into another there's a momentary overlap period where multiple clutches are working against eachother. Harder shifts are because it makes the shift happen quicker, which reduces the clutch slippage durations. In your application i don't see any concerns. Easy life ahead for that Dog.

Slowing down and downshifting should be done in "steps". This isn't an automatic where it's one smooth constant slowdown. Going downhill, I frequently use the brake to slow down close to idle RPM, then execute my downshift, then resume foot brake. If you're finding yourself in situations where you need to have a foot on the brake while downshifting then you're waiting too long to even start slowing down. You're being too rammy. Relax, slow down, take your time. I just went through this training a new driver a year ago.

Shutdown solenoid fault doesn't explain the constant shutdown warning lamp.

It should run longer than that with low oil pressure or low water level. If it's the traditional injection pump then I'd suspect the shutdown lever solenoid. If it's an EUP engine then you can request Blink Codes by holding the Set/Decel cruise switch until the Engine Malfunction Light (lightning bolt) reacts and starts blinking a 2 digit code to you. Example, code 9-2 is engine shutdown without key. Commonly caused by a loose EECU fuse, but basically means an interruption in EECU power circuit. One code is spat out per request. So key on, engine off, hold Set/Decel. When it's done blinking hit it again for next code. Repeat until it starts blinking out the same sequence of codes again. Post any codes here and we'll look em up for you.

You have oil pressure, but your engine shut down light is staying on. How's your coolant level? Also these may use 2 oil pressure sensors. One for the gauge, one for the EECU. Will it continue to run if you hold down the shut down override switch? Can you clarify which fuel system you have? Does this have 6 individual EUP's or one "traditional" style inline injection pump? If you aren't sure then post a picture of the passenger side of the engine, we can tell from that. If it has a "traditional" injection pump then disconnect your shutdown lever on the pump from whatever electric solenoid controls it, put it in the "run" position and see if it'll run.