SHIFTING FROM A STOP WITH HEAVY LOAD

HA!! I saw that too once. A guy from our company with a R model "Western" 350 Mack, came off a scale that had a small hill at the end, when he got halfway up the hill, the motor killed, and he rolled backwards, took his foot off the clutch, in gear, and the thing ran backwards. He put it in 1st and it went backwards ( 10 reverse, 2 forward) He shut it off, started it back up, and off he went. I saw old Detroits do that too.

 

Plan on dinner or so the day after just to be safe. If you don't stay late. I can do it in a day but I have done a bunch of em

 

thanks......

 

On mine I would start off in LO gear that heavy. You don't have to wind up each gear to 1500 rpms. just get the unit moving and shift to the next gear quickly and smoothly. Keep progressively moving and shifting staying in the next higher gear just a little longer.

 

Too many guys hate low gears because they lay the foot down, weedeater revs fast to max before they think to shift.

Put her into 1st, idle should take it away off on level ground. Go to second and rev easy up to third. Now you are walking off. 4th 5th etc. You might as well get used to it, being heavy all the time.

In fact, there are some hills that are dam near vertical at the stop sign and aint no 2nd gear going to work there. That's Lo gear time.

Think slow. Think ease through the revs rather than just flat on the floor and have only maybe a few moments to shift. Your fuel mileage will improve too among other things. Such as ride. It wont beat you up as much. (Think about that tractor as a living thing, if it's beating on you or bucking etc, you aint doing something right. Calm her down....)

To really make headaches for some, some trucks require progressive shifting, example. 1st gear 1500 up to second then 1400 to 3 then 1350 to 4th etc. working steps down towards torque the higher gears you go. You get rolling.

Other trucks don't know anything other than flat out. Those are the old ones thankfully. With lots of room to shift say.... 1400 all the way to 2300... that takes a while.

Still other trucks use standard shifting instead of progressive you shift up at 1500 every time in every gear. Those are easy. You should eventually hear her at 1500.... then shift without thinking.

 

Funny you mention your Mack. I drove a Mack (Mack engine) yesterday and quickly discovered it didn't want to play well in high rpm's. The low end torque was impressive. The customer had set up 65 mph governed speed at 1600 rpm, which is the lowest I have seen for oil field fleets...so far.

 

I will add that most of the oil field trucks I have driven have Cummins engines. Some have Cats. My own truck has a Cummins, but I rarely get it above 1700 and prefer to stay below 1800 unless I have a really heavy load and need to upshift on a steep uphill.

 

Mack engines such as in the Superliner 500, that one you don't "Jam" against speed. But what you could do is load that thing full of rock and use all of it's 15 speeds (Both 15 forward and 15 back...) and get that reduction to take on a Hill at 900 rpm. We used to have lug contests with my foreman who did well, he would report 900 and come over the top loaded, I'll take the next load and try it at 850 and she will do it. It will buck and fight if you blow that 4th down shift and ruin it all. But the best I could managed was right around 870 without it jumping for my boss to see. Speeds were less important, steady movement to the job all day shuttle without stopping, we could with two dumps move 110 yards of stone to build quite a bit of common road.

I would be more than pleased to run some of Lepton1's tractors but they are not red line governed hellcats. But will run very well when asked to do certain things within the limits stated by Lepton1.

Mack is rather short on legs too. It's a little bit more gearing to get through before you make it to 30 and over versus a standard company 10 speed that is already there a gear or two ahead. But the one thing Mack has always done for me is be a mountain goat on ice when things are ... quite fearful. Ive had times where I would select 3rd while empty facing a sheet of wet ice straight down and a 10 mph curve at the bottom... and hope to still be lugging at 8 mph when I hit it. Other wise that flatbed being empty will swing around left and slam into the opposing two lanes of oncoming traffic on that ice.

It's sleeting at the top and somewhat rain at the bottom sometimes. the worst case scenario for me. Ive had moments where if I did not have that mack, I would maybe have slid off or wrecked or whatever.

But they have to be the old macks, if it's a milk truck that only has 5 gears with a shift range between 1200 all the way to 2100 with about 200 rpm room at the bottom and at the top for rock crawling or making a run at a small pull with the fluid piled up in the back, as you go up the momentum wears off as the fluid moves forward preserving a little more of it before you reach the top.

But not all macks are good. Just a certain way of having them built back in the day where they did good. The new ones Im going to have to play with it and see how it goes, but I suspect they are trying to do things that are unnecessary and forget their roots.