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R700 12 Box


nicste
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Hi

Could someone please go over the correct way to shift for neutral trough all the gears (double reduction box). I would like to see what every has to say because ive had guys tell me a lot of contradicting way to drive the rig.

thanks

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depends on the tons your hauling

this is me up to 42.5 tons 1 trailer start off with deep reduction in high 1st low split, 2nd gear low split, 3rd low, split 4th, 5th low split then flick it into high range

up to 75 tons eg 2 trailers start off deep reduction in high range 1st low split, 2nd low split, 3rd low split , 3rd high and continue up splitting the gears

up to 115 tons tripple road train start off with deep reduction in high range 1st low split ,2nd low split, 2nd high split then split all gears onward

if I am am starting on a steep hill with big tonnage eg over 75 tons I might start off in deep reduction but you gotta be real careful as things can break real easy I have broken carrier bearing bolts pretty easy to smoke the drive tyres while waiting for the back trailer brakes to lift off

all this depends on the road and the load

dunno if this answers your question will be interesting see what other people say

Paul

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Yea that helps out nicely, if i'm not mistaken deep reduction should only be used in first gear? How does the splitter on the box work, eg pulling away in 1st low you would switch to direct drive release throttle and when the throttle is applied again the shift happens and it changes in to 1st high, the next shift is to 2nd when ready to split can flip the splitter back ( back into the low positsion??) release throttle and apply it again to shift, and so on through the gears?

Hope you can gather what i am trying to say?

Nic

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deep reduction can only be used in 1st gear there is a mechanical interlock to prevent it been used in any other gear

when I go to split gears I find the truck is moving to slow to warrant splitting most gears 1st-4th for these changes to be worth while with most splitting is in traffic in the lower gears if I was to be running out of revs to low our to high I just give it a flick and and and off the gas and I have got another 400rpm either way

the only thing to be awear of is that once you flick the range change there is pressure on the selector fork were as in road ranger there is only pressure when the gear stick passes through neutral so there is potential to put a lot of were on the selector fork on a Mack box

I was always told if I am climbing a hill to change gears to match the hill ie if I can make it over by splitting a gear then just split the gear if I cant then wait a bit longer and drop a full gear but I think you could only do that with a Mack motor they seem to lug right down like no other motor Ive ever driven

Paul

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Thanks for the info, makes dense to me.

The shift out of deep reduction, main stick to neutral, then shift out of low to high then select first again?

I am also hearing a hissing of air from the transmission when in direct, i am going to trace the lines but is there any other underlying issue that could cause this

Nic

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mate I just push the clutch in pull the stick out of deep reduction I dont shift the main box into neutral

air coming out might mean the pressure regulator on the top of the box is set to high or the air rams need some new o rings if it is coming from around the gear stick might need a kit there either way it wont be much

Paul

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I have notice when the splitter is in the fwd position the exhaust port on the shifter is exhaushting air and when the splittler is moved to the second position from the front i have got no drive.

There is also nothing stopping the main shifter shifting through all the gears when the deep reduction is in low

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