1988 Mack Superliner RW613 Tri-axle heavy hauler.

[Shimmy1]

blue is tractor park

yellow is tractor and trailer park

red is trailer park

Sure told you.

 

[Georgia Iron]

Well guys I am wrenching on this old truck out in the bush. Look what I found. Take is easy on TruckShop his thoughts are welcome.

 

[crane operator]

Well guys I am wrenching on this old truck out in the bush. Look what I found. View attachment 334054Take is easy on TruckShop his thoughts are welcome.

That will make it clunk. Cheaper than diff. troubles, but not a total guarantee that there aren't a few teeth missing in the diff.


You'll get a chance to look at it all, when you pull differential to look for shrapnel, and get the other piece of the axle out.

It could be a lot worse, at least you know where to start looking.

 

[Georgia Iron]

Passenger side looks about 35.5 inches long. I can't believe i got the broke end out with a piece of wood and Copper pipe. Honestly thought it was not coming out the hub side.

 

[Georgia Iron]

To remove the diff i have to remove the 5th wheel assembly. Is that the correct method or since it broke in the tube hit it with a magnet and see what it does?

Anybody got an axle ?

 

[crane operator]

I wouldn't chance the pieces rolling around in the housing, so I'd pull the diff, but you might be luckier than I am.

A good junkyard will have a axle. I don't have any mack toploader axles in my stash. If you post up what you have for rears, I'm sure someone can find them.

 

[Georgia Iron]

I found the transmission tag. Not a lot on google. Appears to be a 12 speed?

 

[shopguy]

The blue button debate could have turned into something epic. LoL

I think coaldust cheated and looked at the pic in post 30 lol

 

[Truck Shop]

It doesn't matter--red charges the trailer, yellow releases/sets tractor brakes, blue is emergency
air release to move when other supply is exhausted. Came into effect in 1971, then dropped
around 1986/87. Problem is/was the leaks at emergency tank/fittings/airlines,
which usually the
emergency tank was out of air too.
*
Large magnet in the bottom of housing--more than likely all the big stuff has collected their,
slap a axle in and run it a ways first to see if there isn't another condition with it. The oil is so thick
the pieces are not going to levitate through thick gear oil. Drive it first to see what else is in
store.

 

[Pops52]

blue is emergency
air release to move when other supply is exhausted. Came into effect in 1971, then dropped

Was this a "Paccar" only thing? The knob on my 72 Pete was green...... The Maxi release above it was "custom built"

 

[Truck Shop]

Was this a "Paccar" only thing?

In those years and before each manufacture used different setups---The early R model Mack
the Williams toggle air release valve was positioned at back of cab between the seats. My 1966
Pete 351 was setup just like yours, only with a fuel primer hand pump on left side of dash along
with compression release T handle.

 

[Coaldust]

Those genuine Bendix TW-1, 2-Position Flipper Dash Control Valves, in that photo, are $120, if you can even find them in stock.

Still common today, as an Emergency shutoff on fuel tankers. I found an imported knockoff that works well.

 

[Truck Shop]

Was this a "Paccar" only thing?

Below are the dash valves in a 1982 W900--note, red charges trailer, will not charge trailer till
yellow main system park valve is pushed in also. Blue is tractor, pushed in for release, but the
blue valve in a properly functioning system will remain in when yellow valve is pulled for park
brakes. It was a redundant system, even with no trailer hooked up the yellow was the primary
park release valve. Valve with blue knob was tied into what was known as emergency air tank,
and some tractors never even came from factory with that tank. It's why the MV3 two button
red/yellow valve system became the norm. Because if you don't hold the red in while pulling
the yellow it will automatically pop the red setting all brakes, holding red in while pulling yellow
valve only sets tractor brakes. The old system set both when yellow was pulled too.
*

 

[Pops52]

Wasn't it around 1976-77 when the 121 system came to be and brought all the pretty colors & shapes of knobs? ON a related story, during a BIT inspection on my 96 pete,the inspector wrote me for having the lettering worn off of the yellow knob.. I said WTF? He said I need to replace it. I said no, its yellow and square and you couldn't read it in the dark anyway so why?? I didnt have to go the jail that day.

 

[JaredV]

Wasn't it around 1976-77 when the 121 system came to be and brought all the pretty colors & shapes of knobs? ON a related story, during a BIT inspection on my 96 pete,the inspector wrote me for having the lettering worn off of the yellow knob.. I said WTF? He said I need to replace it. I said no, its yellow and square and you couldn't read it in the dark anyway so why?? I didnt have to go the jail that day.

We just had a driver get inspected and he was told the same thing. Must be something they look for if they can't find anything else.

 

[Welder Dave]

Sounds like inspector was looking for an infraction and couldn't find one so made one up. The letters are worn off because you know what the valve does and use it.

 

[Georgia Iron]

Found a few spare axles at Richard Kerns here in south Atlanta. I decided to buy a spare for each side. They also rebuild the rear chunks. They have lots of truck stuff on hand of you are happening to need something for your truck. I saw about 100 transmissions, 300 or more rear ends, and lots of axles. I got the only 2 short Mack axles they had one used and one new and and one used long side 17 spline. My ratio rear they did not have but they could turn key rebuild it if i find out it is toast.

After crawling around under the truck in wet cold dirt I have quickly come to the conclusion that taking the bolts out of the housing is going to be a PIA in the field. There is not much room under the truck, even less with the airbags deflated.

 

[Georgia Iron]

Welp i made it back to the truck and used a magnet on a stick to remove the metal shards from inside the axle tube.

Cleaned up the new used axle slid it right back in both sides. Put on the axle nuts fired the truck up and placed it in gear and it jerked and would not move. Seemed like the motor would die. As I was looking in driver side mirror watching the driver side tires it looked like they were completely bound up. I did foward and reverse was pushing in air knobs the blue one pressurized once the yellow one was in. So the blue knob does work and has air on it.

I got out of the truck moved all the slack adjusters and was scratching my head trying to figure out what was happening.

After the third time I looked out the back cab window and realized that both passenger side drive tires were spinning but the truck would not move. I had just filled up all the tires. One tire on the passenger side that had the broken axle was spilt from what ever they hit when they broke the axle. It went back flat.

I checked the top brake pads and they had gaps all the way round. I then proceeded to remove the bottom dust shields on the driver side. The brake pads sit directly on the bottom of the drum. They were practically rust welded to the drum. Crawling under the truck beating with a framing hammer and a small pry bar no luck. I eventually found a piece of rebar rod and a 10lb sledge hammer and about 4 or 6 well placed blows the brake pads broke free from the drums. I could see an air gap. This took about 1.5 hours

Now bear in mind there is not much space under a set of mack rear ends to swing a sledge hammer even less as you are lying under there with it. I turned on the air to the 3rd axle and that gave me about 3 more inches of height. I had to do this while the truck was on because there are a few valves that are attached to the rear brace that seem to adjust ride height or let pressure off the air bag system. One is letting air out so maybe you guys can explain how those rods and valve are supposed to work.

I blocked the tires as I was crawling around under the back end.

I got excited once the brakes broke free. Put the truck in gear and away she went. Turn left on a dirt hill and stuck I was. One back tire would turn then both. But all in all the auto power divider seemed like a joke. I realized that the third axle was taking weight off the drives and raised it back up and the truck started moving.

After a short learning curve on shifting the 12 speed away we went. I was absolutely shocked, In the power that 350 horse motor had. Truly shocked. It would easily leave my big cam Cummings in my dump truck behind.

I got it up to 10th gear at 55 but did not get it to change into 11 or 12 it seemed like it would need to be at 60 or so to get into that last gear. I noticed that when I up shift the gears it does fine going up while using the air L and H switch but spilting the gear going down it seems to hang in neutral so you must put the stick in neutral spilt the return it the lower gear.

As far as reverse it has I think 5 reverse gears. I tried to start out in reverse 3 but it was like it stayed in neutral. But if you start out in low then continue up the reverse gears it will work. I have read that the air shifter seal or something like that periodically needs to be pulled cleaned and resealed. Water and crap in the air lines will give it issues.

Apparently my transmission is fairly rare because Richard's kerns did not and had not had that unit before.

The truck drove straight, stopped straight no play in steering wheel no wierd noises. It rode good even with the one flat. I did not drive it far because I want to check the transmission oil and the front chunks fluid levels.

The engine brake works and the truck sounds bad ass. It cranked right up in 25* weather. It will really blow coal if you lug it around 1200 to 1400 rpms. But at 16 or 1800 it is smoke free.

This truck got dumped over stuck brakes and a broken axle and old looks. I willing to bet it will pull like a mule probably any thing I can hook it to. Might be a bad thing because I might just go get a older d8.

 

[Acoals]

I noticed that when I up shift the gears it does fine going up while using the air L and H switch but spitting the gear going down it seems to hang in neutral so you must put the stick in neutral spilt the return it the lower gear.

On at least some of the Mack tranny's, you don't pre select the range as in a roadranger, you wait until neutral to flip the switch.

 

[Tyler d4c]

Wasn't it around 1976-77 when the 121 system came to be and brought all the pretty colors & shapes of knobs? ON a related story, during a BIT inspection on my 96 pete,the inspector wrote me for having the lettering worn off of the yellow knob.. I said WTF? He said I need to replace it. I said no, its yellow and square and you couldn't read it in the dark anyway so why?? I didnt have to go the jail that day.

Our one truck got fancy chrome ones that say cat.. probably be toss in the fed for it with him!