luke andres

keep in mind too that a 13 speed mack will not have as low of a low gear as the 2070 transmission      in my mind a 13 speed is more of a road tractor transmission      not sure how much you will be using it in the woods pulling out loads of logs      i have a mack book that shows the transmission ratios for all kinds of mack transmissions             and yes more than likely you will have to shorten driveshaft and redo your pto setup

i talked to a guy in pennsilvania and he too had a early 90s dm tri axle dump that he switch out a mack 2070 and put in a 13 speed mack   he also changed from 573 gears down to 442     he said his guys love driving it now    said its like a new truck      i went with the eaton 8ll because     a   its cheaper     and   b   i had one in a parts truck    and   c    it has a lower gear ratio than the 13 speeds    mack or eaton       hope this helps

oh yeah     my mack is a 91 dm 690s  with a 300 em7

i was in  the same situation as you    i had a t2080 mack tranny      3 lows and 5 highs    i had 573 rear gears     i went to an eaton 8ll  and had to switch my rears to 442 to maintain top speed      i like the difference       not such a big jump between gear changes   i had to shorten driveshaft a couple inches    i say go for it     its only money 

hey theakerstwo   was your engine originally a em7 300 horsepower engine    did you do all the work yourself     i would love to get a little more horsepower out of my em7 300        thats why im asking       thanks

just letting all know it was a bad day today      i had 20 ton of rock on my 91 dm tri axle dump when the rear gears started making a lot of noise     since i was only quarter mile from where i was going i limped it there on the shoulder of the road     so tomorrow i guess ill get started taking the rear pumpkin out to see the damage        not fun 

i used one off a r model mack      i had to cut a hole in it for the mirror bracket but it worked fine     it was one that comes from the factory    not a lund brand      i can send u a pic if you want     i did a little custom work to it       i like it alot

just wondering   what is a aneroid    reason im asking is bc i have a 91 em7 with bosch p7100 fuel pump     do i have a aneroid

ok so i have a 91 mack e7 with the bosch p7100 pump that is all factory      what should i do to get some more horse out of this       now its 300 horsepower      id like to be more at 375 or 400      thanks

so now im confused       do i plug off the air line or do i supply it with air?    and yes it does go from the 2080 transmission to the engine manifold

i realize this is a dumb question but how do i post pics on this site     is it better to use a real camera over a cellphone    im fixing up my 1991 dm and id like to show some of my progress      getting her ready for some paint here before long

thanks for the info       so as llong as it has air going to it   it should be fine

so i swapped transmissions on my 91 dm mack 300 em7 engine       there is a air line that went from the mack 2080 transmission up to the intake on the engine       where should i tap this air line into on the truck as the eaton fuller 8ll doesnt have a place to put it            also what does this  air line do

did you have to change turbo and injectors too or just mess with the pump?

the mounts on transmission are definitely different      on my dm I did not have to change the brackets on the frame        mine was a 2 bolt per side set up     

thanks for the feed teamstergrrrl    You are probably right about the running of the engine    Im sure is due for a overhaul      when I decide to do it id like to get it up to more like 350 to 375 horse      Any advice on how     I can sent you some pics of the engine and truck if you want to see it       Its a work in progress     I call it the    Big Stack Mack

the 2080 is a 8 speed  but more like a 5 speed if you will    the 3 lows I never use unless off road        when loaded I can take off in 1st high and only have 4 more gears to go        There is a big jump between gears      I would red line rpms and then grab next gear and she would fall on her face    almost like I skipped a gear       that's why the swap         a guy in pennsilvania did the same thing buy took a 2070 out and put a 2130  mack  tranny in        He said it was a big difference too   

why what? 

I just changed my mack 2080 tranny to a eaton 8LL       I didn't change the pilot bearing       Had to shorten driveshaft and the rear from a 573 to 442 to maintain top end speed      not a bad job to do        love the difference in the truck

so I pulled the 2080 mack tranny out of my 1991 dm tri axle dump and put in a eaton 8LL since my eaton 13 speed mysteriously "walked off"     I'm actually glad thou since the 8LL is more of a dump tranny and the 13 being more for road tractor      I also went from 5:73 to 4:42 rears       Love the difference now and wasn't a bad job to do      Had to shorten drive shaft 3 inches        Now I would like to get a few more horses out of this 300 engine     It has a bosch p7100 all mechanical pump        Any helpful advice would be nice to get        I also have a 94 ch road tractor that is a parts truck with a good 350 engine in it but it has a fuel pump that has electric wires going to it        Not sure if I would be able to just change the turbo and injectors and bump the timing or not          Anyone know        Thanks        

I have a 91 dm690 with a 2080 transmission and 573 rears   its a tri axle dump    I bought 442 rears and a fuller 13 speed rtof12513 that I plan on installing    I think it will make a world of difference     transmission is within a inch of being same length too   

sure beats the hell out of a jeep one never too early to teach them what a mans truck is