rich

Actually, The 12-speed Mack trans was the first trans I ever worked for a living. Never really drove anything for any amount of time before that. I figured it out alot faster than the 13 double over Fuller I drove next. I learned how to back up really good, though, with 6 speeds reverse! I still love that 12 speed. We have 4 trucks with it. The only thing I like better is an 18speed Fuller, but that one's no fun in reverse.

-John

I think i made a mistake on how the 12 speed shifts . I should have said it shifts like a stupid i mean super 10 speed

Not having a 12 speed yet and being dumb to them , how do you shift them, and how does the pattern go.

GG2

Shifts like a 10 speed fuller but there are some cool extras like 2 low hole gears activated by an air switch on dash with a lock out so you can only use them in 1st gear. and reverse is on the slide air valve on shift knob and you have 5 gears in reverse. If you have a pto there is a position on the slide air valve for that but you have to engage your pto seperately also. Tranny is cool but not for beginers i dont think they would make out to well. alot going on with this tranny.

test drove the truck today and man smooth shifting. shifts as good as my 13 speed in my t600. Again thanks for the help!

Buddy

If you have any trouble with the low low remember that there still may be a spring and a ball under the front cover you may have to remove for it to work right with the air shift the truck it came from likly had 2 sticks.

thanks for the help, where else can you get quality help on a sunday Ya"ll are awsome people glade to be a part of this, well i guess i will call it brotherhood.

buddy

1st pic is old tranny 2nd pic is new tranny in truck and ssthird is new tranny in truck so far it seems all air shifters working as i aired up the truck and tried it out

Buddy

I pursuaded a shifter to fit and realized the threaded end was wrong so i welded a bolt on and now that problem is fixed. I think with Ya"lls help i may win this battle. The pics will be up soon!

Buddy

my brother just came home and he is a whiz at this picture stuff

I pursuaded a shifter to fit and realized the threaded end was wrong so i welded a bolt on and now that problem is fixed. I think with Ya"lls help i may win this battle. The pics will be up soon!

Buddy

Bud Post a picture of the trans if you can!OR if your like me have your Kids do it!

Let Us know how you make out on this!

my brother just came home and he is a whiz at this picture stuff

the shifter is a remote air valve with 4 positions i believe if that is what you are talking about'

Buddy

that low low air cyclinder is right next to the shift tower for the stick

superliner 87 has a a plate on the rear box for reverse a one for nuetral i think for a pto then i have a air cylinder for low low with a swith on the dash

buddy

man u know your stuff, that is exactly what it was i saw a pto kinda sitting up on top to the side before they changed it out. what would you do? i have an extra shifter and the technoligy to make it any shape i want. The shift tower is dirrectly below the hole in the cab so a staight shfiter should work i think wada you think??

and if i do try to use it the way it is will the gearing be compatible to the original. so for now i am at a complete stop and will have to wait till tomorrow for more in unless there is a tranny expert watching over me on this site.

buddy

I am R+R a 12 speed 1070b i have the the good tranny in and was about to attach the shifter and noticed that it will not work cause the shifter tower is now on the middle box compared to the front box on the origanal. What the shop did i dont know but i do know the front section was changed out cause the original one had an extra long input shaft. so i am thinking get a shifter that works or yank this tranny out and get one with the shift tower in front section??.

buddy

fjh, did you ever notice that those transmissions (and the 6 speeds too) had a tendency of knocking a tooth off one of the reverse idlers if the driver was rough and had a habit of hitting reverse while the truck was still rolling?

I've seen that quite a few times over the years.

.

I caught myself once doing that just once. I think this tranny is great for some one that knows how it works. It is not your fool proof trannys of today that is for sure.

I Broke my 12 speed and i think the lock out broke and fell down and helped me with the breakage. I am going to install a good take out 12 speed. Anyone have any experience with these trannys? Are they heavy duty? semi bullet proof? The reason i am asking cause the rest of the drive line is massive. I am wondering if the tranny is weak link in the drive line. the truck is a 87 super liner w/44 rears massive drive shaft camel back suspension e6 motor. dump truck

Buddy

I am going to find the problem then go from there. I think it has a broken main shaft

Rob

When i find out i will post it up.

Buddy

What are your plans for the busted one? I have a 1070b that has problems also and would like to have another for spare parts as that damned thing is expensive to repair!!

Thanks,

Rob

I am going to find the problem then go from there. I think it has a broken main shaft

I am replacing a 1070b 12 speed cause the damn thing broke. A while ago i bought this superliner that had a 12 speed and the 2 low hole speeds would not work. After some research and investigation I realized the lock out had broke in half. Though i tried to retrieve the broken parts all i got out was a couple small chunks. Getting back to when i bought this truck the tranny locked up because it was in 2 gears at once. I was able to pop off the shift tower and line the slides up and go on my merry way. After thinking about it i am sure one of the chuncks was the culprit and then finally fell to the bottom. Then after a while reverse was becoming a problem engaging and the nuetral for the pto was a problem. Then the other day I put a little strain on the drive train and snap goes the tranny. No reverse no pto no nuttin. Towed it to the shop and decieded to find a good take out with a garrentee and found one for a $1000.00 could not pass it up. I will pick it up tomorrow and do the swap. I am praying to the MACK gods that i am getting a good tranny. We split it and everything looks good

Has anyone worked in the levee project in new orleans?? I need some work but all i hear is low prices and no pays. I think the army corp is incharge of the work and i see on craigs list there is a great need for dump trucks!

does any one have a plumbing diagram for a 87 superliner e6 puff limiter (reversing valve and valve that connects to the front of injection pump. I want to make sure the air lines are correct. I suspect some guess work was used when this system was hooked up. thanks, Buddy

I need the a/c heater core housing for a 1987 superliner. tried to buy it new but there are none to be had! has the levers for hot and cold and defrost plus the speed control knob for the blower motor. any help woul be appreciated. Thanks , Buddy

thanks for the info, i will be working on it this morning (monday) Buddy

I took the top of thr=e tranny off and found that the lock out that is applied to the cover with a spring and detent ball was broken in half. it is a rectangle box type mechamism thar the shifter tip goes through. looks like it was desinged so when you use deep reduction the only gear that can be used is 1st gear. so i popped it out and now i have deep reduction. Hmmm wonder where the broken piece is Yuk Yuk going to see if i can find one somewhere, man it is a flimsy piece made out of some kind of cast steel or iron if i could see a whole one i could make my own with the part i have :}

if your inch is the same as mine ? 1 inch is almost the stroke of the forks total movment.

You might be able to remove the fork By pushing the rail into the clutch housing! MAYBE!I beleive the lock out is your problem thou no need to remove it!

Tri making a thick gasket from a cerial box and installing it under the lid of the center section where the stick goes thru! 20 thou may let it work again!Also check to make sure when you remove the front cover of the trans that there is NO spring under it! The detent spring is ment for stick shift apllications it shouldn't be there in your app!That somtimes will cause the air style to stick! The shift lock out sticks thru into the next section of the box so you need to remove that lid to access the lock out .But if you pull the lock bolt on the shift fork you will likly be able to slide the shift rail into the belhousing enough fo grind off the lock out ridge on the compound rail!

thanks for the info, i will be working on it this morning (monday) Buddy

I've Seen this happen before!

Where is the cyl located front or second lid back?If it is located in the front lid you can disable the lock out by cutting off the lock out portion of the shift rail !This can be done in the truck.we Need to idenfiy shift lid configuration!!! If the air shift is mounted on the front remove that lid and try to move the fork manually if it moves ok,cut the lock out grooves off of the frist speed shift rail that is sticking thru into the foward case with a zip disc Or grind a bit off the top part of the lock out groove and re assemble. There is also one other Possible fix Buy the proper gasket for that lid that may raise it up enough to clear the lock out groove!

the air cylinder is up front and on drivers side directly next to main shifter i checked and cleaned the cylinder and it works fine tried to move the fork on the shif rail but it only moves i little about 1 inch back and forth and is more forward then back. I am wondering if i can take the shift fork out by sliding the rail back after i take the lock bolt out?