|
Going from a medium class single axle to a heavier class tandem axle is definitely an improvement, more power and better braking, as well increased payloads, and sometimes better traction and front end flotation. One thing I am curious is how you really make use of a 5+2 as a 10 speed, most times when trying to split shift all the gears, it can be really tricky, lot of time you are caught in between and it slams in or you miss, real hard when moving the shift lever too, havinf to use the clutch to shift the rear at the same time, they go so much smoother using the accelerator pedal when the trans is left in gear. I have driven a few that you could split shift, 1 was a high geared 4 spd that would go from 3rd high to 4th low at about 55 or so, then climb to 65, pull up on the button, in 4th low, the truck would do 85 mph or better, was a brand new '86 IH S-1600, the sister to it had a 5 speed and you could not split shift the upper gears, they were too low, this truck would barely do 65 mph. Most I have driven it is a waste of time to fool with that red button too much and use it to split all the gears, even though there is a lable on the sun visor that says you can do it, still sounds like it is going to break something or accelerate wear to the pinion that changes gears. The truck below is the 2 stick Mack, might be the same motor, 5 spd or 6 spd Mack trans, the main trans is 5 and you have auxillary transmission with 2 ranges and reverse if I'm remembering correctly. Personally I've never really liked the transmission arrangement in these, especially a dump truck used for construction applications, carrying max. payloads and dealing with hills etc., but I can honestly state that all the R, RD, and DM models I've driven with them were certainly reliable and do the job, I'd just rather have an 8 speed low hole, 9, 10 or 12 speed mack, anything with some closer ratio'd gears, I drove an R model with 48 foot trailer, hauling lumber, long wheel base, 300+ mack and a 9spd, nice truck with plenty of power and geared right. Those 5 speeds, (thought there was a 6 or are they the same 2 stick trans. just don't count granny low) are just a tad spread out, lots of black smoke when you upshift and that diesel starts to lug, hills can be tough, because once you drop a gear, you can play the back and forth game, up shift, lugs again, pyrometer showing temps getting too hot in the turbo, but that aside, they are tough dependable trucks, don't let my preference for more gears influence you. Be thankful not to have to drive a B-model Mack with a 5+4 20 speed trans and manual steering off road. Many farmers use older trucks like the older macks around here, this one belongs to my neighbor, it was a concrete mixer truck in local batch plant fleet, you know how hammered these can get, I believe he got the chassis, and had the body put on it. Huge capacity, 30 cubic yards struck, 35 cubic yards heaped. It held 14 large square bales, 200 small squares, not sure what the weights are for silage, they hire him out for that and he does all the grain from the combine into it, not sure what the bushel count is, but what a useful truck to have compared to say a single axle. I drove it once last year, used to drive lots of dumps with the same trans, the placard for the shift patterns was missing, boy that makes it tough when going from memory, could not find high range, good thing the fields were close by ! 
|
