IdleUp Posted January 21, 2009 Author Share Posted January 21, 2009 Thanks Guys - I'll keep you posted on my progress. Quote Link to comment https://www.bigmacktrucks.com/topic/7760-intermitent-reverse-problem/page/3/#findComment-29482 Share on other sites More sharing options...
IdleUp Posted January 22, 2009 Author Share Posted January 22, 2009 Ok, you guys have to be getting sick of me with this shifter problem - But I noticed today there is two lines on the end of the aft end of reverse cylinder instead of one. Looks like one goes up to the shifter and the other goes to the frame and hooks into some sort of valve with other lines going to it. Is this a quick release valve or is it something else?Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/7760-intermitent-reverse-problem/page/3/#findComment-29525 Share on other sites More sharing options...
Rob Posted January 22, 2009 Share Posted January 22, 2009 Ok, you guys have to be getting sick of me with this shifter problem - But I noticed today there is two lines on the end of the aft end of reverse cylinder instead of one. Looks like one goes up to the shifter and the other goes to the frame and hooks into some sort of valve with other lines going to it. Is this a quick release valve or is it something else?ThanksI never get sick of trying to help someone with a legitimate problem. I can't help much with the dual line setup as I've never seen it. My service manual does not show that at all. In fact, all the shift covers still show the adjusting nut FJH states was discontinued/changed.Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/7760-intermitent-reverse-problem/page/3/#findComment-29541 Share on other sites More sharing options...
theakerstwo Posted January 22, 2009 Share Posted January 22, 2009 Ok, you guys have to be getting sick of me with this shifter problem - But I noticed today there is two lines on the end of the aft end of reverse cylinder instead of one. Looks like one goes up to the shifter and the other goes to the frame and hooks into some sort of valve with other lines going to it. Is this a quick release valve or is it something else?Thanks Does that air line go to a valve on the intake manifold? Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/7760-intermitent-reverse-problem/page/3/#findComment-29548 Share on other sites More sharing options...
fjh Posted January 22, 2009 Share Posted January 22, 2009 Does that air line go to a valve on the intake manifold?Where Glen is heading with his coment is if it goes forward to the intake it is the torque limit line!if that line is causing issues simply cap it off and plug the t fitting on the trans. Quote Link to comment https://www.bigmacktrucks.com/topic/7760-intermitent-reverse-problem/page/3/#findComment-29554 Share on other sites More sharing options...
IdleUp Posted January 22, 2009 Author Share Posted January 22, 2009 (edited) Where Glen is heading with his coment is if it goes forward to the intake it is the torque limit line!if that line is causing issues simply cap it off and plug the t fitting on the trans.It's so dirty under there it's hard to tell but it looks like it goes up to the cluster at the shifter boot - then the other line goes to some sort of valve mounted on the drivers side frame. I'll trace the line today!The arrow on the this images is almost exactly where the T is located. This is the correct shifter correct? Edited January 22, 2009 by IdleUp Quote Link to comment https://www.bigmacktrucks.com/topic/7760-intermitent-reverse-problem/page/3/#findComment-29577 Share on other sites More sharing options...
fjh Posted January 22, 2009 Share Posted January 22, 2009 It's so dirty under there it's hard to tell but it looks like it goes up to the cluster at the shifter boot - then the other line goes to some sort of valve mounted on the drivers side frame. I'll trace the line today!The arrow on the this images is almost exactly where the T is located. This is the correct shifter correct?Yes Correct.Mark the lines when you take em off . Quote Link to comment https://www.bigmacktrucks.com/topic/7760-intermitent-reverse-problem/page/3/#findComment-29578 Share on other sites More sharing options...
IdleUp Posted January 23, 2009 Author Share Posted January 23, 2009 (edited) Yes Correct.Mark the lines when you take em off .OK, here's a few images of the lines running off the reverse air piston. Two lines are T'ed off with one running to the shifter and the other to this valve - from the valve (like you guys said) it runs to the engine as shown. Can't figure out what this valve does. I didn't get a change to cap the line today, but i will next time I get out there to see if it makes any difference. Thanks Edited January 23, 2009 by IdleUp Quote Link to comment https://www.bigmacktrucks.com/topic/7760-intermitent-reverse-problem/page/3/#findComment-29599 Share on other sites More sharing options...
fjh Posted January 23, 2009 Share Posted January 23, 2009 Its called an inversion valve (sort of a quick release.)Really its a an air operated on/ off valve. There should be two of them.Anyway you can delete the line to the engine if you feel the need. it somtimes can cause greif with power.plug everything thou.bro The lid is not going to fix it's self ya need to get it off and verify what is going on.Having said that thou, somthing that gets negleted on 12 speeds is the air filter Does it have one?Should be on the rh counter shaft cover. If so get a new one.Drain the air before you change it.Check out the diagram left at the first part of your post. Quote Link to comment https://www.bigmacktrucks.com/topic/7760-intermitent-reverse-problem/page/3/#findComment-29614 Share on other sites More sharing options...
theakerstwo Posted January 23, 2009 Share Posted January 23, 2009 Its called an inversion valve (sort of a quick release.)Really its a an air operated on/ off valve. There should be two of them.Anyway you can delete the line to the engine if you feel the need. it somtimes can cause greif with power.plug everything thou.bro The lid is not going to fix it's self ya need to get it off and verify what is going on.Having said that thou, somthing that gets negleted on 12 speeds is the air filter Does it have one?Should be on the rh counter shaft cover. If so get a new one.Drain the air before you change it.Check out the diagram left at the first part of your post. That line in the photo is teed into the manifold, what it leak air into the intake and lose prssure from the trans? Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/7760-intermitent-reverse-problem/page/3/#findComment-29626 Share on other sites More sharing options...
Kav Posted January 23, 2009 Share Posted January 23, 2009 I have a 10 speed that was sometimes hard to get into reverse. What I eventually found was that it had either two or three air pressure regulators on the gearbox, and one of these was faulty and the pressure was not balanced so it would not go into reverse. I replaced the regulator and reset the pressure and it fixed the problem. The airline to the piston at the end of the rack on the fuel pump used to pressurise when the gearbox was in low or reverse gears to limit the torque of the motor. This used to leak air sometimes and after I put a rivet in this line it made it easier to get into reverse and low gears, so it must have been upsetting the pressure also. Best regards - Michael. Quote Link to comment https://www.bigmacktrucks.com/topic/7760-intermitent-reverse-problem/page/3/#findComment-29647 Share on other sites More sharing options...
Rob Posted January 23, 2009 Share Posted January 23, 2009 I have a 10 speed that was sometimes hard to get into reverse. What I eventually found was that it had either two or three air pressure regulators on the gearbox, and one of these was faulty and the pressure was not balanced so it would not go into reverse. I replaced the regulator and reset the pressure and it fixed the problem. The airline to the piston at the end of the rack on the fuel pump used to pressurise when the gearbox was in low or reverse gears to limit the torque of the motor. This used to leak air sometimes and after I put a rivet in this line it made it easier to get into reverse and low gears, so it must have been upsetting the pressure also. Best regards - Michael.The pressure is limited to 60psi with those regulators. They do go bad from condensation, or wet air from the tanks.Never understood the reasoning behind three pressure regulators when a single one on the input, (supply) line will reduce all air to all functions to the proper level.Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/7760-intermitent-reverse-problem/page/3/#findComment-29648 Share on other sites More sharing options...
IdleUp Posted January 24, 2009 Author Share Posted January 24, 2009 (edited) Rob,Thanks a million for the Scans of the air network and the cover removal procedure. I'm going down today to pressure clean the Beast this way I can see what going on.Thanks -Mike Edited January 24, 2009 by IdleUp Quote Link to comment https://www.bigmacktrucks.com/topic/7760-intermitent-reverse-problem/page/3/#findComment-29695 Share on other sites More sharing options...
Rob Posted January 24, 2009 Share Posted January 24, 2009 Rob,Thanks a million for the Scans of the air network and the cover removal procedure. I'm going down today to pressure clean the Beast this way I can see what going on.Thanks -MikeGlad to help.Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/7760-intermitent-reverse-problem/page/3/#findComment-29698 Share on other sites More sharing options...
fjh Posted January 24, 2009 Share Posted January 24, 2009 Glad to help.RobThe inversion valves replaced the regs and the quick release I beleive, there is only one reg now you'll get it figured! Quote Link to comment https://www.bigmacktrucks.com/topic/7760-intermitent-reverse-problem/page/3/#findComment-29703 Share on other sites More sharing options...
IdleUp Posted February 1, 2009 Author Share Posted February 1, 2009 Hey guys - I just posted some images of my Mack on the other board:http://www.bigmacktrucks.com/index.php?sho...amp;#entry30192 Quote Link to comment https://www.bigmacktrucks.com/topic/7760-intermitent-reverse-problem/page/3/#findComment-30194 Share on other sites More sharing options...
fjh Posted February 2, 2009 Share Posted February 2, 2009 Did ya get the trans working yet? Quote Link to comment https://www.bigmacktrucks.com/topic/7760-intermitent-reverse-problem/page/3/#findComment-30207 Share on other sites More sharing options...
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