Mack Doctor Jr. Posted November 5, 2011 Share Posted November 5, 2011 Well Im looking to buy a truck and the one im looking at has a 12 speed. Would it have a .71 final ratio like a 9 spd or an 18 spd?I think I would much rather have an 18 spd over a 9 for sure and splitting of gears on the high side would sure beat the hell out of that. I do realize that the 12 splits on the high side too, I just have never been around them at all. Thanks in advance Joe Quote Link to comment https://www.bigmacktrucks.com/topic/21451-mack-12-speed-question/ Share on other sites More sharing options...
Mutt Posted November 5, 2011 Share Posted November 5, 2011 You will like the Mack trans. Quote Link to comment https://www.bigmacktrucks.com/topic/21451-mack-12-speed-question/#findComment-90046 Share on other sites More sharing options...
Mack Doctor Jr. Posted November 6, 2011 Author Share Posted November 6, 2011 Ive been around tons of macks just not the 12 speed itself. I guess I should have stated it different. LOL Quote Link to comment https://www.bigmacktrucks.com/topic/21451-mack-12-speed-question/#findComment-90048 Share on other sites More sharing options...
greendog32 Posted November 6, 2011 Share Posted November 6, 2011 great trans.had one in my old truck.final is .78 i believe. Quote Link to comment https://www.bigmacktrucks.com/topic/21451-mack-12-speed-question/#findComment-90052 Share on other sites More sharing options...
Mack Doctor Jr. Posted November 6, 2011 Author Share Posted November 6, 2011 thanks Greendog.... sounds like it may have to do for a while and ill just have to get an 18 spd later.. LOL Quote Link to comment https://www.bigmacktrucks.com/topic/21451-mack-12-speed-question/#findComment-90057 Share on other sites More sharing options...
Bollweevil Posted November 6, 2011 Share Posted November 6, 2011 A 12 speed could be either direct or overdrive, they both function the same, but the direct is 1 to 1 in high gear. Quote Link to comment https://www.bigmacktrucks.com/topic/21451-mack-12-speed-question/#findComment-90059 Share on other sites More sharing options...
EWB555 Posted November 7, 2011 Share Posted November 7, 2011 I cant offer any information on the gear ratio, but my truck has a 12 Speed and I love it! Drive like a 5 speed when empty or on a downhill, or split every gear on a pull (or if you like to shift gears) Quote Link to comment https://www.bigmacktrucks.com/topic/21451-mack-12-speed-question/#findComment-90144 Share on other sites More sharing options...
Swishy Posted November 7, 2011 Share Posted November 7, 2011 (edited) I just luv the way mack have thort of drivers by having a good selection of reverse gears th@ can B shiftedprogressively jist like in the forward gears(Clik on pic for a printer friendly size pic of 800 x 1100 pixels)cya§wishy Edited November 7, 2011 by Swishy 1 Quote Link to comment https://www.bigmacktrucks.com/topic/21451-mack-12-speed-question/#findComment-90149 Share on other sites More sharing options...
Lmackattack Posted November 7, 2011 Share Posted November 7, 2011 the 12 speed will also have stronger gears than the 18 speed... IMO the 12 speed is the best trans behind the 300-350 macks. drive like a 5 speed empty and can split them all when loaded. most times I would just run 1-2-3 in direct then split 4th and 5th. some times only needing to split 5th. great when trying to keep the RPMs up on a hill. or keep EGTs down. Quote Link to comment https://www.bigmacktrucks.com/topic/21451-mack-12-speed-question/#findComment-90160 Share on other sites More sharing options...
mackniac Posted November 8, 2011 Share Posted November 8, 2011 Hi !not a very experience driver but yes the Mack 12 is a very good tranny very versatile and lovely to shift Quote Makniac , collector and customizer of die-cast model in 1/50th scale Link to comment https://www.bigmacktrucks.com/topic/21451-mack-12-speed-question/#findComment-90270 Share on other sites More sharing options...
greendog32 Posted November 9, 2011 Share Posted November 9, 2011 ya bollweevil is right.look on side of trans.if it says trtxl107 its 1 to 1.trtxl1070 is overdrive .78. Quote Link to comment https://www.bigmacktrucks.com/topic/21451-mack-12-speed-question/#findComment-90395 Share on other sites More sharing options...
scotsman Posted November 30, 2011 Share Posted November 30, 2011 I just luv the way mack have thort of drivers by having a good selection of reverse gears th@ can B shiftedprogressively jist like in the forward gears(Clik on pic for a printer friendly size pic of 800 x 1100 pixels)cya§wishyI rebuilt one of these in collage. Great unit solid and lovely. Quote Link to comment https://www.bigmacktrucks.com/topic/21451-mack-12-speed-question/#findComment-92519 Share on other sites More sharing options...
rsb502 Posted December 6, 2011 Share Posted December 6, 2011 ya bollweevil is right.look on side of trans.if it says trtxl107 its 1 to 1.trtxl1070 is overdrive .78.I had the TRTXL 1070 in my 84 Super Liner behind an E-9 you cant match the power to the tranny any better than that setup with 4:42 rears it will pull every trail on the interstate all by itself, I believe the correct trans numbers are the trtxl 1070 is 1:1 and the trtxl 1070B is OD I had looked into replacing my 1070 with the 1070 b to get the OD make sure you replace the screw on air filter on the trans every service they get moisture and crud in the air solenoids and act a fool then you have to take them apart and clean them out and go back together again ( I did it twice takes me a while to get the hint) of course my truck did not have an air dryer it had the screw on air filter on the tranny newer trucks may be set up differently but either way water and crud = bad! Quote "Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin"If your gonna be STUPID, you gotta be TOUGH" "You cant always get what you want, but if you try sometimes you get what you need" Link to comment https://www.bigmacktrucks.com/topic/21451-mack-12-speed-question/#findComment-93094 Share on other sites More sharing options...
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