bisley57 Posted May 10, 2009 Share Posted May 10, 2009 Glad to have found this forum.I have recently been assigned a different truck,concrete pump truck on an MR 688 with an E-7 400 engine,with a T-310 transmission.The first time I range shift from lo to hi while leaving out a distinctive grind is heard from the transmission,but does not happen for the rest of the day.I believe the is the beginning of the end for the synchronizer.or am I wrong.I was taught to always pre-select ,please tell me if I am wrong,never to shift from lo to hi or hi to lo without being IN a gear.If the range select lever is changed while in neutral damage to the synchronizer will occur.This truck was operated by someone else for almost a year and I believe his shifting procedures were wrong,i.e.,range shifting in neutral.Now,with it grinding only one time in the morning could this mean there is a problem with the o-rings in the range shift valve or synchronizer cylinder due to some kind of binding or shrinkage over night?I am not sure for the proper part but the cylinder that is on the back of the transmission that has 2 air lines running to it,could the inside be dirty or scarred preventing problems in the morning?I am looking for some help although I think it is the beginnings of synchronizer failure.Any ideas? Quote Link to comment https://www.bigmacktrucks.com/topic/9340-range-shift/ Share on other sites More sharing options...
bisley57 Posted May 10, 2009 Author Share Posted May 10, 2009 (edited) How about a dirty range shift valve filter? Edited May 10, 2009 by bisley57 Quote Link to comment https://www.bigmacktrucks.com/topic/9340-range-shift/#findComment-34990 Share on other sites More sharing options...
fjh Posted May 10, 2009 Share Posted May 10, 2009 Glad to have found this forum.I have recently been assigned a different truck,concrete pump truck on an MR 688 with an E-7 400 engine,with a T-310 transmission.The first time I range shift from lo to hi while leaving out a distinctive grind is heard from the transmission,but does not happen for the rest of the day.I believe the is the beginning of the end for the synchronizer.or am I wrong.I was taught to always pre-select ,please tell me if I am wrong,never to shift from lo to hi or hi to lo without being IN a gear.If the range select lever is changed while in neutral damage to the synchronizer will occur.This truck was operated by someone else for almost a year and I believe his shifting procedures were wrong,i.e.,range shifting in neutral.Now,with it grinding only one time in the morning could this mean there is a problem with the o-rings in the range shift valve or synchronizer cylinder due to some kind of binding or shrinkage over night?I am not sure for the proper part but the cylinder that is on the back of the transmission that has 2 air lines running to it,could the inside be dirty or scarred preventing problems in the morning?I am looking for some help although I think it is the beginnings of synchronizer failure.Any ideas?Your method is correct!However begining of the end for the synro may be premature there is a good posibility that the synco is on its way out time will tell that!I would however check the yoke bolt on the rear of the trans to see if it is tight that can cause the same intermitant patern. Quote Link to comment https://www.bigmacktrucks.com/topic/9340-range-shift/#findComment-34991 Share on other sites More sharing options...
bisley57 Posted May 10, 2009 Author Share Posted May 10, 2009 Your method is correct!However begining of the end for the synro may be premature there is a good posibility that the synco is on its way out time will tell that!I would however check the yoke bolt on the rear of the trans to see if it is tight that can cause the same intermitant patern. It only happens when the truck is range shifted the first time in the morning,with a loose yolk wouldn't it happen periodically all day?Is there an air regulator that can be adjusted to increase air pressure to the synchronizer cylinder to give it a little more uumph. Quote Link to comment https://www.bigmacktrucks.com/topic/9340-range-shift/#findComment-34992 Share on other sites More sharing options...
fjh Posted May 10, 2009 Share Posted May 10, 2009 It only happens when the truck is range shifted the first time in the morning,with a loose yolk wouldn't it happen periodically all day?Is there an air regulator that can be adjusted to increase air pressure to the synchronizer cylinder to give it a little more uumph.the trans gets system preasure.If the problem gets worse worry about it then once in the morning is not going to be much of a problem could be sticky orings. Quote Link to comment https://www.bigmacktrucks.com/topic/9340-range-shift/#findComment-35007 Share on other sites More sharing options...
bisley57 Posted May 10, 2009 Author Share Posted May 10, 2009 the trans gets system preasure.If the problem gets worse worry about it then once in the morning is not going to be much of a problem could be sticky orings.Wondering if a little lube would help.I am thinking of taking the range shift valve filter out and see if it is dirty,if I can get to it.Thank you for your help. Quote Link to comment https://www.bigmacktrucks.com/topic/9340-range-shift/#findComment-35009 Share on other sites More sharing options...
fjh Posted May 10, 2009 Share Posted May 10, 2009 Wondering if a little lube would help.I am thinking of taking the range shift valve filter out and see if it is dirty,if I can get to it.Thank you for your help.If you lift up on the range lever in gear and then take it out of gear you should hear it expell air then hear the range shift!If you hear rhe air expell and no range clunk its likly not the range valve more likly orings in the range cyl in the lid.They tend to get oil in them and have a little stickyness till the oil warms and thins out. Quote Link to comment https://www.bigmacktrucks.com/topic/9340-range-shift/#findComment-35013 Share on other sites More sharing options...
bisley57 Posted May 10, 2009 Author Share Posted May 10, 2009 If you lift up on the range lever in gear and then take it out of gear you should hear it expell air then hear the range shift!If you hear rhe air expell and no range clunk its likly not the range valve more likly orings in the range cyl in the lid.They tend to get oil in them and have a little stickyness till the oil warms and thins out. Any thing I need to look for if I take the range cylinder apart?No springs or anything that may fly out?I would assume it is like a PTO engagement cylinder,a disc/piston with an o-ring. Quote Link to comment https://www.bigmacktrucks.com/topic/9340-range-shift/#findComment-35016 Share on other sites More sharing options...
bisley57 Posted May 10, 2009 Author Share Posted May 10, 2009 Any thing I need to look for if I take the range cylinder apart?No springs or anything that may fly out?I would assume it is like a PTO engagement cylinder,a disc/piston with an o-ring. From a mechanical point of view why do you have to range shift in gear,what is the physical difference of how the synchronizer acts if you range shift in neutral? Quote Link to comment https://www.bigmacktrucks.com/topic/9340-range-shift/#findComment-35017 Share on other sites More sharing options...
fjh Posted May 10, 2009 Share Posted May 10, 2009 From a mechanical point of view why do you have to range shift in gear,what is the physical difference of how the synchronizer acts if you range shift in neutral?The range shift is locked in to one side or the other if you pull the lever into nutrel then lift the lever the everything is in free wheel the interlock helps prevent this!Nothin in there thats going to fly very far! Quote Link to comment https://www.bigmacktrucks.com/topic/9340-range-shift/#findComment-35018 Share on other sites More sharing options...
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