Title: OC-46 clutch
Post by: deronnelson on July 24, 2005, 11:28:14 PM
Post by: deronnelson on July 24, 2005, 11:28:14 PM
I have an OC-46 that I recently repaired the clutch on (new clutch disks). I adjusted the clutch as the shop manual instructs. The clutch no longer slips, but when the clutch is let out while the crawler is out of gear and then pressed in again, the gears grind and is thus difficult to get into gear. If I am in a gear and press the clutch in to shift to another gear it does not grind. I did not replace the throw out bearing when I repaired the clutch as it looked to be in excellent condition. Any advice on how to correct this problem would be greatly appreciated.
Deron
Deron
Title: OC-46 Clutch
Post by: John Schwiebert on July 25, 2005, 12:58:04 AM
Post by: John Schwiebert on July 25, 2005, 12:58:04 AM
Did you check the pilot bearing? it would be more suspect than the throutout bearing. How much free travel do you have? Do you have the correct oil and oil level in the transmission? Is trhis agas or a diesel since you had mentioned disks? Your turn
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Post by: andy b. on July 25, 2005, 02:22:05 AM
Post by: andy b. on July 25, 2005, 02:22:05 AM
Deron,
i don't know how familiar you are with the old Oliver crawlers (and old non-synchro trannies in general), but it seems to me you are pretty much describing how the tranny seems to work in most of the old stuff i've driven. in fact, i have a John Deere Model 40 tractor, a 1957 OC-46, and have driven a bunch of other old farm equipment and it does just as you describe.
first, if the tractor is in gear and you put the clutch in and come to a stop, then none of the gears in the tranny are moving (if they were, you wouldn't be stopped, since you are in gear). if you go to shift to a different gear, the gears obviously cannot grind, since for them to grind they would need to be moving, and you are stopped.
now, let's say you are in gear, put the clutch in, and come to a stop. now you take the tranny out of gear and let the clutch out. you will not move (because you are not in gear), but the input shaft to the tranny as well as any gears directly connected to it will now start spinning. if you put the clutch in and quickly go to shift it into gear, those shafts and gears may still be spinning, and you will grind the gears. it seems in these older transmissions the shafts are so worn in, that they have enough momentum to keep turning a bit until the forces of friction bring them to a hault.
like i said, i have found this to be true in any old non-synchromesh transmission i have driven. in my mind, there really isn't a problem with your tranny. you just can't drive it like a 2005 Mustang GT.
andy b.
i don't know how familiar you are with the old Oliver crawlers (and old non-synchro trannies in general), but it seems to me you are pretty much describing how the tranny seems to work in most of the old stuff i've driven. in fact, i have a John Deere Model 40 tractor, a 1957 OC-46, and have driven a bunch of other old farm equipment and it does just as you describe.
first, if the tractor is in gear and you put the clutch in and come to a stop, then none of the gears in the tranny are moving (if they were, you wouldn't be stopped, since you are in gear). if you go to shift to a different gear, the gears obviously cannot grind, since for them to grind they would need to be moving, and you are stopped.
now, let's say you are in gear, put the clutch in, and come to a stop. now you take the tranny out of gear and let the clutch out. you will not move (because you are not in gear), but the input shaft to the tranny as well as any gears directly connected to it will now start spinning. if you put the clutch in and quickly go to shift it into gear, those shafts and gears may still be spinning, and you will grind the gears. it seems in these older transmissions the shafts are so worn in, that they have enough momentum to keep turning a bit until the forces of friction bring them to a hault.
like i said, i have found this to be true in any old non-synchromesh transmission i have driven. in my mind, there really isn't a problem with your tranny. you just can't drive it like a 2005 Mustang GT.
andy b.
Title:
Post by: deronnelson on July 25, 2005, 02:40:59 AM
Post by: deronnelson on July 25, 2005, 02:40:59 AM
The pilot bearing looked ok. This a a 3 cyl. gas engine. It has a forward/reverse shuttle transmission. There is SAE 50 oil in the transmission and shuttle. There is approx. an inch and a half free travel of the clutch pedal. It is like an unsynchronized transmission, it is just that even if I leave the clutch pressed in for a couple of minutes it still grinds. Maybe I just shouldn't worry about it and lower the throttle and shove it into gear?? Thanks for your comments!
Deron
Deron
Title:
Post by: andy b. on July 25, 2005, 01:37:18 PM
Post by: andy b. on July 25, 2005, 01:37:18 PM
Deron,
don't just shove it into gear (at least not too hard).
my OC-46 is an older 4 cyl. gasoline model (1957) but i believe it should be similar to yours for debugging purposes. i just have a plain old manual tranmission with the differential steering, no shuttle shift or exotic rear end. on mine i can look down between my feet and see the universals on the drive shaft spinning. can you see this on yours (there may be a small cover there). have the tractor running with the clutch out and not in gear, then push the clutch in and watch to see what that driveshaft does. does it keep spinning at full speed, or start to slow down?
even if i am at half throttle or less and push the clutch in, i can see that stub driveshaft spin for probably a minute. the inertia of the clutch disk also adds into the equation and acts like a small flywheel to keep things spinning. what i normally do is slow the throttle to initially shift into gear from neutral, and once the clutch is out i bump the throttle up. if i am runnign and shifting from one gear into another, there is no problem, just as you have observed.
i am not sure what others do, but when i am going from neutral into a gear, and the tranny gears are still spinning, i slowly move the shifter towards the gear i want. you can feel the gears starting to touch, and if you just sort of lightly bump the gears together, it will stop the input shaft from spinning and you can shift into gear. you shouldn't hear any grinding when you do this. i really can't see any other way to do it unless you wait two minutes for the driveshaft to stop spinning or try to idle the engine down to 300 RPMs somehow. while i am sure this does create some minute amount of wear when doing this, most of the stuff i drive is at least 50 years old and when i've had any opportunity to look inside the transmissions, they've looked fine (no noticeable wear), and no metal particles come out when changing fluids.
andy b.
don't just shove it into gear (at least not too hard).
my OC-46 is an older 4 cyl. gasoline model (1957) but i believe it should be similar to yours for debugging purposes. i just have a plain old manual tranmission with the differential steering, no shuttle shift or exotic rear end. on mine i can look down between my feet and see the universals on the drive shaft spinning. can you see this on yours (there may be a small cover there). have the tractor running with the clutch out and not in gear, then push the clutch in and watch to see what that driveshaft does. does it keep spinning at full speed, or start to slow down?
even if i am at half throttle or less and push the clutch in, i can see that stub driveshaft spin for probably a minute. the inertia of the clutch disk also adds into the equation and acts like a small flywheel to keep things spinning. what i normally do is slow the throttle to initially shift into gear from neutral, and once the clutch is out i bump the throttle up. if i am runnign and shifting from one gear into another, there is no problem, just as you have observed.
i am not sure what others do, but when i am going from neutral into a gear, and the tranny gears are still spinning, i slowly move the shifter towards the gear i want. you can feel the gears starting to touch, and if you just sort of lightly bump the gears together, it will stop the input shaft from spinning and you can shift into gear. you shouldn't hear any grinding when you do this. i really can't see any other way to do it unless you wait two minutes for the driveshaft to stop spinning or try to idle the engine down to 300 RPMs somehow. while i am sure this does create some minute amount of wear when doing this, most of the stuff i drive is at least 50 years old and when i've had any opportunity to look inside the transmissions, they've looked fine (no noticeable wear), and no metal particles come out when changing fluids.
andy b.
Title:
Post by: mtncrawler on July 25, 2005, 04:01:18 PM
Post by: mtncrawler on July 25, 2005, 04:01:18 PM
Did you change the pressure plate too or just the clutch disc? Try taking most of the free play out of the adjustment so you only have an inch or so of free pedal.
Title: OC-46 Double plate clutch
Post by: John Schwiebert on July 26, 2005, 12:11:11 AM
Post by: John Schwiebert on July 26, 2005, 12:11:11 AM
Please refresh my memory. How is that center plate installed? I think I have the double plate Spicer (Now Eaton) truck clutches on my mind. I know they only have a couple of thousands clearance or you have problems with the drive disks dragging. Also how was the pilot bearing checked and what is your idle speed? A little heavier oil in the reverser only may also help.
Title:
Post by: deronnelson on July 26, 2005, 11:55:43 PM
Post by: deronnelson on July 26, 2005, 11:55:43 PM
Thanks for all or your advice. If I throttle it down and wait long enough I can edge it into gear without too much grinding. Maybe I will try a little heavier weight oil. What a great discussion list.
Deron
Deron