nasty51ford Posted December 25, 2014 Share Posted December 25, 2014 Hi, I have a triplex double over transmission in my B67, it was a swap, it came with a duplex direct 10 speed. My auxiliary box (the three speed) shifts very quickly, the main box however (the five speed) is very slow shifting, with, or without the clutch, is there any way to remedy this? Merry Christmas All !! Quote Link to comment https://www.bigmacktrucks.com/topic/38210-slow-shifting-main-box/ Share on other sites More sharing options...
mowerman Posted December 25, 2014 Share Posted December 25, 2014 move both sticks at once,,,good luck...bob Quote Link to comment https://www.bigmacktrucks.com/topic/38210-slow-shifting-main-box/#findComment-271781 Share on other sites More sharing options...
Freightrain Posted December 25, 2014 Share Posted December 25, 2014 The main box is always a slow shift just due to the rpm drop it takes. The splits are only 300 rpm and goes quickly. Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/38210-slow-shifting-main-box/#findComment-271800 Share on other sites More sharing options...
nasty51ford Posted December 26, 2014 Author Share Posted December 26, 2014 Yep, I figured it was just the nature of the beast. I was just hoping there may be a way to get the RPM's to drop faster, I remember an "86" R model I use to drive back in "86" it had a 6 speed ( 5 speed with the Lo Hole) and there was an aneroid (puffer) valve they disconnected to make the RPM' s drop quicker so you could shift it quicker, and it would give it back it's bottom end grunt too! I know the old Spicer 5+4's and 4+4's I use to run shifted slower on the main box too, but not this damn slow! Lol. Quote Link to comment https://www.bigmacktrucks.com/topic/38210-slow-shifting-main-box/#findComment-271817 Share on other sites More sharing options...
nasty51ford Posted December 26, 2014 Author Share Posted December 26, 2014 I have tried doing them both at once Bob, like I used to do with the old Spicers, but......no help, it's just a waiting game for the RPM's to drop, all that two stick shifting at the same time doesn't really accomplish anything, just cool to show off with the grandkids! lol. If I had a Jake on it, I could shift the main much quicker!! Did they even make a Jake brake for the old END 673's ? Quote Link to comment https://www.bigmacktrucks.com/topic/38210-slow-shifting-main-box/#findComment-271818 Share on other sites More sharing options...
theakerstwo Posted December 26, 2014 Share Posted December 26, 2014 Only way to speed up shift is put a jake brake on it. Years back when I worked macks often I worked on this one truck that the driver used the jake on ever main box split and it was a pleasure to listen to him shift.I use a jake on mine only to knock the rpm down when in low gears coming out of the pit up hill.We was on a job last spring that required stopping on a hill.When we all would take off all of the other trucks would run in low gear for about three block till the hill leveled out some. With a jake you can pass all of them and they know not why because I don't run a straight pipe. Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/38210-slow-shifting-main-box/#findComment-271821 Share on other sites More sharing options...
nasty51ford Posted December 26, 2014 Author Share Posted December 26, 2014 Yep, that's why I said I could shift that main box a lot faster with a Jake Quote Link to comment https://www.bigmacktrucks.com/topic/38210-slow-shifting-main-box/#findComment-271838 Share on other sites More sharing options...
Freightrain Posted December 26, 2014 Share Posted December 26, 2014 Tec Brake makes the jake for a mack. $1500 was the last price I remember. Don't know how well they actually work on these low compression motors. Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/38210-slow-shifting-main-box/#findComment-271850 Share on other sites More sharing options...
nasty51ford Posted December 26, 2014 Author Share Posted December 26, 2014 Hmmmmmmm, a bit pricey just to shift quicker! Lol. Guess I'll just have to live with it! Quote Link to comment https://www.bigmacktrucks.com/topic/38210-slow-shifting-main-box/#findComment-271872 Share on other sites More sharing options...
Freightrain Posted December 26, 2014 Share Posted December 26, 2014 Thus I never got one myself. 1 Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/38210-slow-shifting-main-box/#findComment-271875 Share on other sites More sharing options...
theakerstwo Posted December 26, 2014 Share Posted December 26, 2014 Larry you ant missed anything. 1 Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/38210-slow-shifting-main-box/#findComment-271879 Share on other sites More sharing options...
j hancock Posted December 26, 2014 Share Posted December 26, 2014 They make noise... 1 Quote JimIt doesn't cost anything to pay attention. Link to comment https://www.bigmacktrucks.com/topic/38210-slow-shifting-main-box/#findComment-271919 Share on other sites More sharing options...
Freightrain Posted December 26, 2014 Share Posted December 26, 2014 What I heard about it. 1 Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/38210-slow-shifting-main-box/#findComment-271920 Share on other sites More sharing options...
HK Trucking Posted January 11, 2015 Share Posted January 11, 2015 Disconnecting or disabling the puff limiter will do absolutely nothing to make the RPM drop quicker. It WILL make the engine accelerate more rapidly once you catch the next higher gear, the side effect being black clouds of smoke from the exhaust until the turbocharger "catches up" & starts pushing in enough air for a clean burn. Quote "If You Can't Shift It Smoothly, You Shouldn't Be Driving It" Link to comment https://www.bigmacktrucks.com/topic/38210-slow-shifting-main-box/#findComment-273947 Share on other sites More sharing options...
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