Transmission issue
#1
Hello all

I am a mustang newbie. I purchased a Mach 1 a couple months ago. Beautiful numbers matching, I will send photo when I can. Having tranny issues. Hurst 4 speed. This has probably been brought up somewhere on this site before I am sure, and if so I apologize. Occasionally(more and more lately) when I start it and warm it up, will only go into reverse, will not go into 1,2,3 or 4th gear, despite trying and trying. Usually I have to turn the car off and eventually will slip into first second their or fourth gear, then i can re start vehicle and go. has gotten me into a couple of tight spots when it has occurred.... Any help appreciated. I am in Portland OR anyone who knows where I can take it to be looked at also appreciated. 

I attached a photo of me at Portland International raceway taken yesterday.

Thanks 

LH
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#2
[attachment=13320 Wrote:rads410 pid='40835' dateline='1627234488']Hello all

I am a mustang newbie. I purchased a Mach 1 a couple months ago. Beautiful numbers matching, I will send photo when I can. Having tranny issues. Hurst 4 speed. This has probably been brought up somewhere on this site before I am sure, and if so I apologize. Occasionally(more and more lately) when I start it and warm it up, will only go into reverse, will not go into 1,2,3 or 4th gear, despite trying and trying. Usually I have to turn the car off and eventually will slip into first second their or fourth gear, then i can re start vehicle and go. has gotten me into a couple of tight spots when it has occurred.... Any help appreciated. I am in Portland OR anyone who knows where I can take it to be looked at also appreciated. 

I attached a photo of me at Portland International raceway taken yesterday.

Thanks 

LH


Attached Files Image(s)
   
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#3
SSig_welcome4 Looks like a beautiful car. Welcome and enjoy the site. Lots of good people, and info. Now on to your problem. for some reason the clutch is dragging on the flywheel / pressure plate instead of releasing, and stopping. Not allowing to put the car in gear, when you push the clutch pedal. Check your clutch linkage. You should have about 1 inch or a little less of freeplay in the clutch pedal, before you feel the resistance of the pressure plate, anymore then that, and it can cause drag on the clutch disc, causing your issue. Is the Z bar installed, correctly, and not worn? There is a ball stud on the side of the block, which one end of the Z bar goes over, and another ball stud, bolted to the frame/body. Any looseness, or worn parts in this area can also cause these problems. Check your drivers side motor mount, and make sure it hasn't broken or pulled apart, as that will let the left side of the engine rock up under torque, and can even pull the Z bar off the ball studs. If all these things are good the clutch disc may be coming apart, or swelled from damaged, or the last guy who put a clutch in it put grease on the splines, and clutch dust has mixed with it, and is sticking the clutch disc on the shaft not allowing it to float on the splines, and creating a drag on the flywheel or the pressure plate. Which doesn't allow the trans to stop turning, which stops you from putting it in gear. Hope it helps let us know.  Cool

JTS
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#4
Like JTS mentioned it could very well be a clutch issue.  The odd thing is you mentioned it will go into reverse and not first, second, third, or fourth gears.  If the clutch was not disengaging you wouldn't be able to get it into reverse without some gear grinding/crunching noise.  Does it make any gear grinding/crunching noise when going into reverse?  That's the an obvious symptom of a clutch not disengaging.

To be clear when stopped with the engine idling, push down the clutch pedal and the trans will go into reverse but not any of the other gears?  But when the car is rolling you can shift it fine through 1-4 gears?

You didn't mention what motor is in the car?  If it's a 351W it should have a 164 tooth flywheel, 11" dia. clutch, and clutch linkage specific to a 351W.  I have seen when somebody has mixed clutch and linkage parts for a 302 motor.  There are some that think all small block parts interchange but the 351W has some unique parts.  Clutch, flywheel, bellhousing, and clutch linkage are some of them.

More information would help.  At this point it's difficult to determine if it's a clutch/linkage issue, or the blocker rings and/or other synchro parts are worn out.
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#5
Thanks for the great info!
I will let you know what we come up with.



JTS71 Mach1SSig_welcome4 Looks like a beautiful car. Welcome and enjoy the site. Lots of good people, and info. Now on to your problem. for some reason the clutch is dragging on the flywheel / pressure plate instead of releasing, and stopping. Not allowing to put the car in gear, when you push the clutch pedal. Check your clutch linkage. You should have about 1 inch or a little less of freeplay in the clutch pedal, before you feel the resistance of the pressure plate, anymore then that, and it can cause drag on the clutch disc, causing your issue. Is the Z bar installed, correctly, and not worn? There is a ball stud on the side of the block, which one end of the Z bar goes over, and another ball stud, bolted to the frame/body. Any looseness, or worn parts in this area can also cause these problems. Check your drivers side motor mount, and make sure it hasn't broken or pulled apart, as that will let the left side of the engine rock up under torque, and can even pull the Z bar off the ball studs. If all these things are good the clutch disc may be coming apart, or swelled from damaged, or the last guy who put a clutch in it put grease on the splines, and clutch dust has mixed with it, and is sticking the clutch disc on the shaft not allowing it to float on the splines, and creating a drag on the flywheel or the pressure plate. Which doesn't allow the trans to stop turning, which stops you from putting it in gear. Hope it helps let us know.  Cool

JTS
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#6
Hello and thank you.


Yes  when this happens, the car is stopped with engine idling, I push down the clutch and it goes EASILY into reverse, no grinding, no problem! But will not go into 1,2,3 or 4th gear. When I finally do get it in gear, I am able to drive it as usual, all gears work. To get this to happen, I usually shut the car off, wait, then I can usually gently get it into a gear, any gear, I start it back up and its business as usual. Its the 428 big block with cobra jet.

Thanks again

Lloyd




1969_Mach1Like JTS mentioned it could very well be a clutch issue.  The odd thing is you mentioned it will go into reverse and not first, second, third, or fourth gears.  If the clutch was not disengaging you wouldn't be able to get it into reverse without some gear grinding/crunching noise.  Does it make any gear grinding/crunching noise when going into reverse?  That's the an obvious symptom of a clutch not disengaging.

To be clear when stopped with the engine idling, push down the clutch pedal and the trans will go into reverse but not any of the other gears?  But when the car is rolling you can shift it fine through 1-4 gears?

You didn't mention what motor is in the car?  If it's a 351W it should have a 164 tooth flywheel, 11" dia. clutch, and clutch linkage specific to a 351W.  I have seen when somebody has mixed clutch and linkage parts for a 302 motor.  There are some that think all small block parts interchange but the 351W has some unique parts.  Clutch, flywheel, bellhousing, and clutch linkage are some of them.

More information would help.  At this point it's difficult to determine if it's a clutch/linkage issue, or the blocker rings and/or other synchro parts are worn out.
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#7
It's starting to sound like an transmission issue.  Possibly worn out blocker rings/synchro assemblies, maybe some gears as well.  The teeth on the gears that engage with the synchro hubs eventually wear out.  There are also things like worn detents binding in the shift rails.

HOWEVER,  if it were my car, first thing I would do is change the trans fluid and make certain you refill it with only a non-synthetic API GL4 rated gear oil.  Not something that is API GL4 and API GL5 rated.  Over time, the additives to create the API GL5 gear oil oxidizes soft metal parts like the brass blocker rings or brass thrust washers inside the trans.  Also, the API GL5 rated gear oils are more "slippery" and the brass blocker rings will not work correctly.  Gear Oil (4speedtoploaders.com)  Summit racing also carries the correct gear oil.  Most parts stores do not have the correct gear oil for older cars like these.  I would also check the shift linkage adjustment to be certain it's okay.

In the end, if it comes down to trans issue, David Kee Toploaders has all the parts needed for these transmissions.  He will also rebuild yours if do not want to try it yourself.  Store Home (4speedtoploaders.com)  He seems to be the last remaining expert on these transmissions.  When I rebuilt my toploader, after completely disassembling it,  I sadly found more parts worn than not.  You will need some special snap ring pliers and a hydraulic press or something else to safely remove and install the front and rear bearings.  And the detents for the shift rails are a bit tricky to get in the correct locations.
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#8
(07-27-2021, 05:09 AM)Interesting. I\ll start with changing the transmission fluid. Sounds like the cheapest option lol.I had read about Bill Heeley over in Maryland as a good contact as well. Is he still around?Many thanks for the advice, I'll let you know what happens after fluid change. Wrote: It's starting to sound like an transmission issue.  Possibly worn out blocker rings/synchro assemblies, maybe some gears as well.  The teeth on the gears that engage with the synchro hubs eventually wear out.  There are also things like worn detents binding in the shift rails.

However,  if it were my car, first thing I would do is change the trans fluid and make certain you refill it with only a non-synthetic API GL4 rated gear oil.  Not something that is API GL4 and API GL5 rated.  Over time, the additives to create the API GL5 gear oil oxidizes soft metal parts like the brass blocker rings or brass thrust washers inside the trans.  Gear Oil (4speedtoploaders.com)  Summit racing also carries the correct gear oil.  Most parts stores do not have the correct gear oil for older cars like these.  I would also check the shift linkage adjustment to be certain it's okay.

In the end, if it comes down to trans issue, David Kee Toploaders has all the parts needed for these transmissions.  He will also rebuild yours if do not want to try it yourself.  Store Home (4speedtoploaders.com)  He seems to be the last remaining expert on these transmissions.  When I rebuilt my toploader, after completely disassembling it,  I sadly found more parts worn than not.  You will need some special snap ring pliers and a hydraulic press or something else to safely remove and install the front and rear bearings.  And the detents for the shift rails are a bit tricky to get in the correct locations.
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#9
Changing the trans fluid first is a good idea.

NOTE:  Before knowing of the GL5 and GL4 differences I filled my trans with a Lucus GL 5 rated gear oil after I rebuilt it.  I got into situations where I could not down shift until I was stopped.  I changed to the Brad Penn API GL4 oil and all was fine.
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#10
One last thought is aligning the shifter, and shift rods. If it's not going to full neutral everytime you come out of reverse, it will lock it out of all forward gears. There should be a hole in the side of the shifter, I believe it should be 5/16. Take a 5/16 drill bit, and see if you can insert the smooth end into the hole, and through the shifter arms. If it goes in smoothly then the shifter arms are aligned. If not you will have to adjust the shift rods until you can insert it smoothly. Hope it helps. 

JTS
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