Transmission Swap

[Roypom]

I'm wanting to swap a transmission in my truck, it currently has the Maxforce T2070 7 speed, it is to far apart in gears to pull loaded.  It is a dump truck and transfer trailer, the truck and trailer grosses  at 96,000 pounds. What tranny would be best suited to replace the 7 spd with?  And if I go to a Eaton what do I need to change out?

[terry]

pretty hard to change that set up unless you change rears too. the 2070 has about a 5.50 rear end ratio.    terry

[1965]

Trade trucks; money ahead. Just an opinion. No harm meant 

[Vladislav]

T2070 (and T2080,T2060,T2050) all have the overdrive of 0.60 Mack T2090 9 speed which would work the way you want has the top notch of 0.71. The same with T2100 10 speed whicj is quite similar to T2090. Knowing your drive axle ratio and doing the count you will learn how your maximum speed or an actual spped at some particular revs would drop. Going from T2070 to T2090 you will have 0.6/0.71=0.85 of your current speed. For example if you do 60mph with some revs now you will be at 60x0.85 = 51mph. Another point T2070 were in two sizes of the housing (and many other T200 series boxes too). T2090 was always in the short bow and T2070 usually (or always?) in the long. So prop shaft modifying would be required.

Currently I'm close to the moment of swapping T2090 with T2070 in my R688. So catched some facts over them both. But I'm not with a done deal yet.

Sure some other options such as Fuller etc could be applied but I'm not familiar with those trannies.

Edited May 6, 2018 by Vladislav

[Maxidyne]

Adding gears isn't going to make a Maxidyne go any faster, even with the wide ratio 7 speed it's always putting over 90% of full power out, even lugged down to the downshift point. And as Terry said,  you'd have to swap the transmission AND two rear gear sets, and this is the time of year you need your truck out working instead of haunting the shop. BTW, which Maxidyne engine do you have and what year and model Mack?

[luke andres]

i have a 91 dm690 tri axle em7 engine    i went from a 2080 mack tranny to an eaton fuller 8ll     also went from 573 rears to 442     love the different setup     not such a big jump between gears     you will need the bellhouse that accepts the mounts and also the mount brackets as the mack engines have the engine mounts on the bellhouse       i also had to shorten the drive shaft     hope that helps

[Maxidyne]

And after a week or more of work swapping out half the drive train you can keep the engine in a 290 to 300 HP power band instead of a 270 to 300 HP power band, figure in the power interruptions from the extra gearshifts and it's probably a wash. Same with fuel consumption, might improve a bit if you use the extra gears to keep RPMs down, but the fueling gets screwed up with every gearshift and you're making more gearshifts. Waste of time and money to do that in a 20+ year old truck, would make more sense to trade for a different truck with more gears to shift if that's what you want.