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Mackpro68


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That trans does have a .71 overdrive in 18th gear like most Mack trans so it would be OK. Maybe alittle more trans than you need for on-road use. However most Mack 13 and 18 speeds Macks are exactly the same trans except for the shift knob which lets you split the low side. The T318LR is only different from the T318 by having a lower gear in 1 and 2, the rest of the ratios are the same

i copied and pasted this from an earlier post from mackpro68

i have a 13 speed mack trans all i have to do to make it an 18 speed is change shift knobs??????

the reason im asking is reverse is so slow its embarrasing if some one is waiting on me, but i do like the option of the super low reverse, i would like to split it some times

or could i just dissasemble 13 speed shift knob and alter it to allow split in low side????????

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That trans does have a .71 overdrive in 18th gear like most Mack trans so it would be OK. Maybe alittle more trans than you need for on-road use. However most Mack 13 and 18 speeds Macks are exactly the same trans except for the shift knob which lets you split the low side. The T318LR is only different from the T318 by having a lower gear in 1 and 2, the rest of the ratios are the same

i copied and pasted this from an earlier post from mackpro68

i have a 13 speed mack trans all i have to do to make it an 18 speed is change shift knobs??????

the reason im asking is reverse is so slow its embarrasing if some one is waiting on me, but i do like the option of the super low reverse, i would like to split it some times

or could i just dissasemble 13 speed shift knob and alter it to allow split in low side????????

Charlie I have personaly never done this but!I have heard you can take the knob apart and break off the lock out mechanisum Its plastic I beleive!

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Charlie I have personaly never done this but!I have heard you can take the knob apart and break off the lock out mechanisum Its plastic I beleive!

All we have ever done is just change the knob but the knob is $$$. So you might be able to mod the knob as FJH said but I dont know how.

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Go to Mack and price a new knob...

After you pick up your jaw...you'll soon realize it'll be better money spent getting your old knob polished a few times...

If that's all that seperates a 13sp from an 18sp...why even bother with making a 13sp to begin with?

Ever wonder how a blind person knows when to stop wiping?

gallery_1977_876_21691.jpg

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A 13 speed does not have gearing for deep reduction, it only has overdrive. A 18 speed has both deep reduction aka double underdrive and over drive. If you want under drive and not over then get a 15 speed with double over aka old school 15 which has 4/5 and 9/10 holes reversed. This will give you the same top gear as a 13 or 18 speed but the deep reduction so you can split the low gears. This is only needed in a dump truck or a heavy hauler. If you were building a heavy hauler then your better off with the 18 speed so you have the best of both worlds. Just my .02

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A 13 speed does not have gearing for deep reduction, it only has overdrive. A 18 speed has both deep reduction aka double underdrive and over drive. If you want under drive and not over then get a 15 speed with double over aka old school 15 which has 4/5 and 9/10 holes reversed. This will give you the same top gear as a 13 or 18 speed but the deep reduction so you can split the low gears. This is only needed in a dump truck or a heavy hauler. If you were building a heavy hauler then your better off with the 18 speed so you have the best of both worlds. Just my .02

[/quote

Speaking of an Eaton Fuller, You are looking at a different final ratio of .89 in the 13 speed, and .73 in the 15 over. The 13 is a basic 9 speed with an overdrive rear box. You can double a 13, and set your hair on fire, by over driving the main box. You can not double a 15 over as it is an over driven 10 speed in the front and under drive in the rear. You might create a double over, in your dreams by mix matching the front and rear boxes. If only they would mate up? If only you could find an auxiliary drive gear that would work? To what purpose though? A 15 over with a tall gear and enough engine to pull it works just fine. The deep reduction is just the icing on the cake, for pulling out of a hole without spilling your load.

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A 13 speed does not have gearing for deep reduction, it only has overdrive. A 18 speed has both deep reduction aka double underdrive and over drive. If you want under drive and not over then get a 15 speed with double over aka old school 15 which has 4/5 and 9/10 holes reversed. This will give you the same top gear as a 13 or 18 speed but the deep reduction so you can split the low gears. This is only needed in a dump truck or a heavy hauler. If you were building a heavy hauler then your better off with the 18 speed so you have the best of both worlds. Just my .02

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A 13 speed does not have gearing for deep reduction, it only has overdrive. A 18 speed has both deep reduction aka double underdrive and over drive. If you want under drive and not over then get a 15 speed with double over aka old school 15 which has 4/5 and 9/10 holes reversed. This will give you the same top gear as a 13 or 18 speed but the deep reduction so you can split the low gears. This is only needed in a dump truck or a heavy hauler. If you were building a heavy hauler then your better off with the 18 speed so you have the best of both worlds. Just my .02

This is a MACK 13 speed. The low hole is fine. The top hole is fine. Just need to split the reverse gear. Reverse gear is embarassingly slow if someone is waiting on you to get out of their way.

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Put it up in the high side and goose it! Then you'll REALLY get the flock outta the way....and look like a snake on time lapse video!

I feel for ya...I have the 18sp with the SLOOOOOOOOOOOOOWWWWWWWWWWWWWWWW reverse...splitting it up doesn't do much. I either just wind the piss out of the motor and get there eventually or I put in the high side and go back'erds. My trans in high reverse at idle is about the same speed as a regular reverse at full throttle...if that makes any sense.

There have been times where I've had to back up over a mile and it's nice in this respect because others who try the high side backwards either can't or they bounce the shit out of their trucks trying to get it rolling only to quit because they can't keep it going straight.

Ever wonder how a blind person knows when to stop wiping?

gallery_1977_876_21691.jpg

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Go to Mack and price a new knob...

After you pick up your jaw...you'll soon realize it'll be better money spent getting your old knob polished a few times...

If that's all that seperates a 13sp from an 18sp...why even bother with making a 13sp to begin with?

More money for nothing!

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Ahh well...I like my 18sp. Being able to split any gear is nice...especially when I'm just puttin around and don't feel like doing much. I don't think I'd buy another truck w/o one.

Ever wonder how a blind person knows when to stop wiping?

gallery_1977_876_21691.jpg

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Ahh well...I like my 18sp. Being able to split any gear is nice...especially when I'm just puttin around and don't feel like doing much. I don't think I'd buy another truck w/o one.

I had an 18 speed in the 2001 CL713 and loved it. What I heard that the shift knob was the only difference. I would really like to have and 18 speed in my CH.

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Mackpro68 This is real easy to check if you have an 18. While in any low range gear, shift the range splitter to high and then you should be able to split that gear. The lockout in the gear shift works off of the range spitter, (heard tell you could take it apart and file the lock off, don't know for sure).

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Mackpro68 This is real easy to check if you have an 18. While in any low range gear, shift the range splitter to high and then you should be able to split that gear. The lockout in the gear shift works off of the range spitter, (heard tell you could take it apart and file the lock off, don't know for sure).

I was told by a Mack Dealer a few years ago all you had to do was drive a roll pin out that prevented it from splitting in the low side. That was on a 1999 CH

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I was told by a Mack Dealer a few years ago all you had to do was drive a roll pin out that prevented it from splitting in the low side. That was on a 1999 CH

I beleive this is correct

It means dismantaling the shift knob is all!

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