Right now I am looking at a mid-90s Mack RD tri-axle dump truck with an E7 mechanical 350 and an 8ll.
If I buy this truck I’m just curious how a 13 speed would do, because I have one that is like new.
As I have done research on Mack Trucks and transmissions and gear ratios, it got me thinking that I wanted to ask a few questions to drivers that have really spent time in these trucks.
I used to drive these trucks of this era in the mid-90s.
I drove for one company that had a 6-speed like a T2060 transmission. Mated to the 300 horsepower engine, that combination was good.
It wasn’t fast but it seemed like that truck was designed in such a way for that gearing. Like it all worked together the way it was designed to.
That’s a really good setup for a truck that’s a local vocational truck, like say something for a paving contractor.
Then I’ve driven the Mack Rd with a 350/ 400 engines, and they had 8ll transmissions.
I don’t remember thinking I needed more gears. I seem to remember the same feeling that the truck was all designed to work together as one and it did it really well.
Much faster than the 300 and the power was much more even and able to get up to road speed and it just worked better.
That’s set up was 100% great for a tri-axle dump truck that’s going to work in a larger area than just the immediate town.
It had plenty of power to take you up and down Hills and from what I remember the trucks would cruise at 65 or maybe even 70.
So my question to you guys that have spent a lot of time in these trucks is that is there any advantage to going to a 13 speed or an 18-speed transmission?
It seems like a tricky question for me because the Mack is just different than everything else. The way that that engine pulls is just like nothing else.
For example, if you got a little more RPMs out of your engine and you could shift around 1400 or 1500, the Mack would just pull your right from there up, no problem, better than it would at the 1200- 1300 I think you normally fall to.
Maybe more gears or being able to split them would do something similar?
So I don’t know, does more gears help when you have an engine that pulls like that?
If you’ve driven both setups, I’m curious what you think.
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