10 Speed Mack Transmission

[b61mack]

i have a TRDL1070 Mack 10 speed transmission i was thinking of putting in my B model behind a 237, i would like to here the pros and cons of the 1070, is it an overdrive and the same transmission as a 12 speed except the extra low gear. is it as good as the 12 speed, you here about the 12 but nobody talks about the TRDL1070. Thanks Ron

[storkmack]

My dad had one in a Crusie Liner back in the day. Multi speed reverse, spiltable gears. He really liked it. I haven't seen one since. I think it would be a fine trans for behind 237. Brad

[GearheadGrrrl]

The 237, like all Maxidynes, was designed with a broad torque curve so it only needs a wide ratio 5 speed for on highway applications. The 6 speed added one more lower gear for on/off road applications. The 10 and 12 speeds are basicly the wide ration 5 or 6 speed with a second "splitter" feature to "split" each of the 5 or 6 gears, giving a 10 or 12 speed transmission. The 237 like all Maxidynes doesn't absolutely need a 10 or 12 speed transmission, but the extra gears don't hurt and they can add some flexibility.

[theakerstwo]

The 237, like all Maxidynes, was designed with a broad torque curve so it only needs a wide ratio 5 speed for on highway applications. The 6 speed added one more lower gear for on/off road applications. The 10 and 12 speeds are basicly the wide ration 5 or 6 speed with a second "splitter" feature to "split" each of the 5 or 6 gears, giving a 10 or 12 speed transmission. The 237 like all Maxidynes doesn't absolutely need a 10 or 12 speed transmission, but the extra gears don't hurt and they can add some flexibility.

Your right and that is the cadillac of trans if you have a 237 0r 285 engine for as the 12 speed goes. I like it because on a long pull you can cut the rpm back some.

[terry]

I owned a DM with a 285 turned up and a 12 spd. overdrive with 4.17 rears, absolutly the best combo i ever drove. you could not believe the trucks i could outrun. But it sure liked the fuel if you kept your foot in it. terry

[b61mack]

The 237, like all Maxidynes, was designed with a broad torque curve so it only needs a wide ratio 5 speed for on highway applications. The 6 speed added one more lower gear for on/off road applications. The 10 and 12 speeds are basicly the wide ration 5 or 6 speed with a second "splitter" feature to "split" each of the 5 or 6 gears, giving a 10 or 12 speed transmission. The 237 like all Maxidynes doesn't absolutely need a 10 or 12 speed transmission, but the extra gears don't hurt and they can add some flexibility.

So the 10 and 12 speeds are wide ratio transmission like the 5 speed,you could drive it like a 5 speed then for cruiseing you could use overdrive to lower the RPM. i have 4.17 rears on 20" rubber, anyone no offhand what speed it would run. Thanks Guys Ron

[Superdog]

So the 10 and 12 speeds are wide ratio transmission like the 5 speed,you could drive it like a 5 speed then for cruiseing you could use overdrive to lower the RPM. i have 4.17 rears on 20" rubber, anyone no offhand what speed it would run. Thanks Guys Ron

Roughly 78 mph.

[dak49]

Your right and that is the cadillac of trans if you have a 237 0r 285 engine for as the 12 speed goes. I like it because on a long pull you can cut the rpm back some.

I think you could actually get a little better fuel mileage from a 10 or 12 speed by shifting earlier and keeping the engine in the high torque rpm range. I think that's what Mack did with the "Econodyn" engine, they cut the rpm back to 1800 then used a 9 speed or more gears to help keep the engine rpm closer to 1200-1300.

One of the problems though was Mack didn't have any real high speed rear gears to get your speed back, hence the overdrive transmissions.

I could be wrong about my info, but I'm pretty sure I am close to correct.

Have a good day

Dak49

[ThaddeusW]

The 237, like all Maxidynes, was designed with a broad torque curve so it only needs a wide ratio 5 speed for on highway applications. The 6 speed added one more lower gear for on/off road applications. The 10 and 12 speeds are basicly the wide ration 5 or 6 speed with a second "splitter" feature to "split" each of the 5 or 6 gears, giving a 10 or 12 speed transmission. The 237 like all Maxidynes doesn't absolutely need a 10 or 12 speed transmission, but the extra gears don't hurt and they can add some flexibility.

I read up on this and The 12 speed is indeed the same as 1070 but with the addition of yet another aux section that was either a stick or dash mounted air switch. It gave you two very low gears like a 2 stick 6 speed. You kept the switch/stick in hi for on road stuff and you had 10 forward and 5 reverse gears. Set the switch/stick to lo and you used only first and second for two deep reduction gears. From what I hear its one heck of a big tranny.

[b61mack]

I read up on this and The 12 speed is indeed the same as 1070 but with the addition of yet another aux section that was either a stick or dash mounted air switch. It gave you two very low gears like a 2 stick 6 speed. You kept the switch/stick in hi for on road stuff and you had 10 forward and 5 reverse gears. Set the switch/stick to lo and you used only first and second for two deep reduction gears. From what I hear its one heck of a big tranny.

Thanks guys it sounds like a good combo,i have to put a new clutch in so it would be a good time to change the transmission, one more question will the big driveshaft and U joints be too much weight for the rear bearings on the trans. i have 3 of those transmissions and they all take the small driveshaft. Thanks again. Ron

[MACKS]

I have two trucks with 12 speeds and they both have the big u joints,just in case you don't know,that tranny comes in overdrive and direct,so make sure you check the numbers on the side of the tranny.Good Luck

[bulldogbred]

I have the 12 speed in my 1975 RS700L behind a E7400 Mechanical, and I LOVE IT! I don't think I can tell you how much I like this tranny. We have two RD's one with a 400 and one a 350 both have 8LL's, we also have a CL with a ISX600 and an 18 spd, and I will be honest with you I will take the old R700 any day over the CL, more low end power, and that 12 speed just drives like a Cadillac, once you get rollin you only need to use two gears because like a 5 speed 4th gear is high enough to do 40-45 and low enough to do 30 for rollin into a town. I hardly ever use the Low gear in my 12 speed only when you get in real soft ground when I'm off road.