mpnichols Posted March 23, 2009 Share Posted March 23, 2009 Need advise on how to downshift. Can't get into gear. I have purchased a 1988 RW713 Superliner E9 motor. Do not know the made of trans. It is a 12 speed w 4 air selection on the shifter ( H,D,N,R ). Upshifts fine. Quote Link to comment https://www.bigmacktrucks.com/topic/8758-how-to-downshift-12-speed/ Share on other sites More sharing options...
MACKS Posted March 24, 2009 Share Posted March 24, 2009 First you have to remember the trans gears are always spinning the faster the truck is going the faster the gears are spinning,to down shift you need to raise the rpm of the engine to match the tran speed,when you get it just right the gears will mesh together. Practice makes perfect Quote Link to comment https://www.bigmacktrucks.com/topic/8758-how-to-downshift-12-speed/#findComment-32560 Share on other sites More sharing options...
Mack700 Posted March 25, 2009 Share Posted March 25, 2009 I don't know how to explain it to you any better. but let me tell you that once you master the Mack 12 speed it will be the best transmission you can have behind that E9 Quote Link to comment https://www.bigmacktrucks.com/topic/8758-how-to-downshift-12-speed/#findComment-32621 Share on other sites More sharing options...
ducky698 Posted March 25, 2009 Share Posted March 25, 2009 I don't know how to explain it to you any better. but let me tell you that once you master the Mack 12 speed it will be the best transmission you can have behind that E9 Thats pretty much it. if your shift change for going up gears is say a 400 rpm drop per gear change then for a down shift the rpm would be around 400 higher than your current rpm.Grant Quote Link to comment https://www.bigmacktrucks.com/topic/8758-how-to-downshift-12-speed/#findComment-32627 Share on other sites More sharing options...
HK Trucking Posted March 25, 2009 Share Posted March 25, 2009 Thats pretty much it. if your shift change for going up gears is say a 400 rpm drop per gear change then for a down shift the rpm would be around 400 higher than your current rpm.GrantUnless your just downshifting a whole gear with the stick, and not using the splitter, then it's about 900 RPM. Quote "If You Can't Shift It Smoothly, You Shouldn't Be Driving It" Link to comment https://www.bigmacktrucks.com/topic/8758-how-to-downshift-12-speed/#findComment-32631 Share on other sites More sharing options...
brutus998 Posted April 4, 2009 Share Posted April 4, 2009 Need advise on how to downshift. Can't get into gear. I have purchased a 1988 RW713 Superliner E9 motor. Do not know the made of trans. It is a 12 speed w 4 air selection on the shifter ( H,D,N,R ). Upshifts fine.It is a sweet tranny!!!What I do if you want to downshift 1 gear from High to directs just take your foot off the accelerator and flip the splitter from High range down to direct range then push foot back on accelerator.With my V8 12 speed I dont split a whole lot. Essentially if you have a lot of trouble shifitng and splitting(direct to high) then just shift it like a 5 speed. Unless there is a huge grade I wont split until 4th and 5th holes.Hope this helps!!! Quote Link to comment https://www.bigmacktrucks.com/topic/8758-how-to-downshift-12-speed/#findComment-33148 Share on other sites More sharing options...
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