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Discussion Starter #1
Hi all I’m facing something with may manual transmission, it is hard to shift backward and it is impossible to shift to the 1st while my truck is moving.



I changed the transmission oil.
Where to look?
 

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Your clutch is probably not releasing. Have you tried adjusting it? What kind of vehicle/transmission?
 

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We would need to identify the transmission. But if it's NP435 like you say in your other post DO NOT try to shift into first gear while the truck is moving. First gear is a slider and you could peel the teeth off of the cluster gear/first gear slider if you push too hard on the shift lever. This is the same for the SM420 and SM465 and countless other manual transmissions dating before 1962-ishesque. First gear is NOT a synchro-mesh gear and is NOT meant to be shifted down into while moving.
 

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what kind of tranny do you have if its a 4 speed im assuming then this will be your shift pattern
L 2
-N-
1 3 R
while the truck is moving dont try to put it in "L" (low) youll screw up the gears and by backward im taking it you mean downshifting if it up shifted it should downshift unless your rpms are way too high even then it should still go in gear (although i wouldnt advise it) try to adjust your clutch
 

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First gear is probably not synchroed, if its one of the above mentioned light truck transmissions. Although I have found that if my truck is moving slightly, 1st gear will engage...

Reverse is sometimes a bitch, but only because the gear teeth aren't aligned for engagement.

I quick shift into another gear always does the trick.
 

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We would need to identify the transmission. But if it's NP435 like you say in your other post DO NOT try to shift into first gear while the truck is moving. First gear is a slider and you could peel the teeth off of the cluster gear/first gear slider if you push too hard on the shift lever. This is the same for the SM420 and SM465 and countless other manual transmissions dating before 1962-ishesque. First gear is NOT a synchro-mesh gear and is NOT meant to be shifted down into while moving.
Just because a gear is not sychronized does not mean that you can not engage it while the vehicle is moving. You just have to know how.
 

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Just because a gear is not sychronized does not mean that you can not engage it while the vehicle is moving. You just have to know how.
With the transmissions mentioned here, one of which he most likely has(SM), the first and reverse gears have to be slid in and out of engagement with mating gear teeth and not just coupled to a shaft via a coarse tooth dog-clutch. While it is true that with perfect sychronization and absolutely no torque inbalance on either gear they can be slid into engagement w/o damage, but for granny first gears and reverse this speed is very slow. It is very unwise to use the gear teeth to try and equalize the speed between the meshing gears, especially if either side has a torque load on it, i.e vehicle momentum on output; engine torque/clutch engaged on input. On the constant-mesh, synchronized gears, a clutch pad equalizes the two gear speeds to each other and the dog-clutch teeth are much coarser than real gear teeth and are designed to engage and disengage under slight load w/o damage.

Checking the clutch adjustment is a good idea. learning what you have and how to operate it is another. When you want to shift into first, be stopped, put the tranny in second to stop the input shaft from free-spinning then directly into first while the clutch is still in. To put it in reverse while stopped, put it first in 4th gear to stop the input, then directly over to reverse while the clutch is still pushed in. If you still have grinding, the clutch linkage is probably too loose to fully disengage the clutch from the input. If this works for you, in time and with practice you will learn the timing and limits of shifting these unmeshed gears with little or no harmful grinding.
 

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With the transmissions mentioned here, one of which he most likely has(SM), the first and reverse gears have to be slid in and out of engagement with mating gear teeth and not just coupled to a shaft via a coarse tooth dog-clutch. While it is true that with perfect sychronization and absolutely no torque inbalance on either gear they can be slid into engagement w/o damage, but for granny first gears and reverse this speed is very slow. It is very unwise to use the gear teeth to try and equalize the speed between the meshing gears, especially if either side has a torque load on it, i.e vehicle momentum on output; engine torque/clutch engaged on input. On the constant-mesh, synchronized gears, a clutch pad equalizes the two gear speeds to each other and the dog-clutch teeth are much coarser than real gear teeth and are designed to engage and disengage under slight load w/o damage.

Checking the clutch adjustment is a good idea. learning what you have and how to operate it is another. When you want to shift into first, be stopped, put the tranny in second to stop the input shaft from free-spinning then directly into first while the clutch is still in. To put it in reverse while stopped, put it first in 4th gear to stop the input, then directly over to reverse while the clutch is still pushed in. If you still have grinding, the clutch linkage is probably too loose to fully disengage the clutch from the input. If this works for you, in time and with practice you will learn the timing and limits of shifting these unmeshed gears with little or no harmful grinding.

for people that cannot drive a maanual transmission you are correct.
for the rest you can shift into and out of any gear in the case while moving, easier without using the clutch or double clutching.
synchros are for women
 

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Discussion Starter #9
the transmission is as mentioned (NP435)

L 2
-N-
1 3 R

i'm not talking about downshift from 1st to L while moving,my problem is downshift from the 3rd to the 2nd while moving but not fast and even when i'm stop it also hard to engage to 1st gear from the 2nd, i need to push hard to engage gear.
 

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Worn needle bearings under the gears making them line up poorly would be my guess. It could also be contamination, wear or galling in the shift rails themselves or other wear in the internal shift components like shift lever pivot. 3 to 2 could be a worn out synchro. If that is all, double-clutching to synch it should ease the shift. If it doesn't help, I'd say its bearings. It sounds like it needs a good look inside.
 

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Discussion Starter #11
still having trouble.... even while i'm not moving the L gear would not engage easily a ruff sound.......:(
 

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still having trouble.... even while i'm not moving the L gear would not engage easily a ruff sound.......:(
Is the clutch releasing??????????????????????????
 

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still having trouble.... even while i'm not moving the L gear would not engage easily a ruff sound.......:(
shut the engine off, and try it. if it is still hard, issue is in transmission.
if no problem, clutch is not dis-engaging completely; adjust/service clutch.
 

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Your clutch is not dis-engaging all the way. if you cannot adjust,
( to less "free" feel in pedal ) time to replace...
 
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