I've been thinking - if by idle you mean the car is sitting still, then the shifter is fine and so is the clutch. When you're moving, the mainshaft spins in time with the rear wheels, and the gears spin around the mainshaft on needle bearings. If one of these bearings got gunked up and doesn't want to spin correctly, the countershaft/gears won't want to slide into gear as easily and your synchros are doing extra work. This would be noticeable in all gears, but moreso at higher speeds.

A shift fork problem usually only affects one gear, but if it's bent or gunked such that it causes drag on the clutch sleeve, it could also prevent the countershaft/gears from spinning freely and have the same hard shifting in all gears.

Unfortunately both issues involve a full tranny teardown and rebuild. You could drain the oil and replace it, seeing if anything funny comes out as a clue.

Dave

 

Then...

Which is it? You say it was rebuilt and then you say it wasn't rebuilt, it merely had the 5th gear synchro replaced. Are you certain you know how to identify worn synchros?

Worn synchros and/or selectors. If those are known good the tranny needs broken in. Does it get better as it warms up? If the tranny was not in fact rebuilt and the effort is the same even after warm up then you have worn synchros and/or selectors. If the tranny parts are new and it gets better as it warms up it most likely needs break in.

It doesn't have anything to do with spinning, it has to do with the fact of whether a load is present or not. When you're moving the gearbox is actually under a load, when sitting in place at idle it is not. If the gearbox isn't driving the car then the gearbox isn't loaded; that's what makes the difference in shifting effort between sitting at idle and moving the car under power. It's not anything to do with bearings, spinning, gunk etc.

 

This might sound stupid but I ahd the same problem because I put my hand on the shifter like side mount and when i started shifiting from the top up the gears get there much smoother.....Don't flame dudes just my situatiion

 

since we're on the topic of trannys (Sorry to butt in gamezilla), after i installed my B&M, 4th gear is stupid now. it either clunks into 4th, or grinds. i really gotta be patient (even with rev matching.. cant even heel toe from 5th->4th b/c of this) when going into fourth. this is obviously a sychro problem?

 

Sell B&M buy Re Amemiya

 

Anytime the clutch is used to aid a shift the tranny is unloaded. Now I recall someone mentioned powershifting - all bets are off if you're shifting clutchless.

I was referring to the tranny when shifting with the clutch working properly - which of course means the tranny is unloaded. And the text I quoted about the shifting being fine at idle suggests they are comparing clutched shifts.

I am postulating what could be wrong if the car shifts fine when the car is stopped, but not fine when it's shifted on the roll. Again, using the clutch as it's intended, thereby unloading the tranny in both cases. TCB and Gamezilla, I'd like to know if that's indeed what's happening. In that case, then something that adds friction to the assembly (a pinching shift fork, grit in the needle bearings, etc) would apply a load to the gears and countershaft and make shifts clash.

But it's all postulation - a full rebuild is the only way to rule out such a problem.

Dave

 

Engine power is removed with the clutch disengaged, but that doesn't mean the gears are completely unloaded.

With the engine running, the car at rest and the clutch disengaged the input shaft is not turning (clutch is disengaged) and the output shaft is not turning either (rear axles not spinning). The transmission is completely at rest.

When the car is moving down the road and the clutch is disengaged the input shaft will no longer have power fed into it but the output shaft is still driven since the axles are turning. Granted this is not near as much power as the engine puts through the 'box but this is more than plenty to cause increased shift effort on a worn tranny because one end of the tranny is still being driven even though the clutch is disengaged. The transmission is never completely at rest if the car is traveling down the road.

 

I think we're in agreement overall. My quoted statement applies for a rolling car, but only for the moment when the tranny is out of one gear and not yet in the next gear (neutral). So grinding noticed as you try to put the car into another gear occur with the countershaft spinning freely, and at a relatively similar speed to mesh with the output shaft. Any mismatch in speed handled by the synchros will be to change the speed of the countershaft and gears. If the synchros aren't up to the job, or the bearings in the gears are not spinning freely, or the clutch forks are adding enough friction to slow the cshaft down, you'll see more grinding.

Dave

 

Tranny was rebuilt about 10k miles before I bought it. The previous owner had just cracked the 5th gear syncro before he took it out. I bought it, replaced 5th gear, and inspected all the other selectors/syncros for any signs of wear/griniding. Everything looked almost brand new. They had only replaced half the bearings so I replaced the remaining ones.

 

dgeesaman & DamonB, very helpful explanations. By the way, what I call "powershifting" is still using the clutch but not lifting the accelerator.

 

Mine is difficult to shift with the car off as well. Sometimes it'll go in smoothly, other times it wont want to let me in at all.

 

pilot bearing

 

Transmission makes no abnormal noise. Plus if it was the pilot bearing it would let me in just fine with the car off. That is not the case.

 

Has anyone ever figured out this problem because I have it too and its driving me crazy.. wont go into gear at all.. car on or off.

 

I've never had this happen before but it must have something to do with your shifter forks being bent or something.

Not going in gear when the car is off is pretty freaky.

I can't help but wonder if it's possible that some sort of drive line alignment isn't causing the problem these other folks have.

Anyways form what I'm reading it doesn't make much sense.

 

do you have a lighttend flywheel?

 

maybe its out of linement. could aftermarket motor and def. mounts be the solution???
so while you set still it would go in gear easy.
but when going, the motor&trans tork and move just slightly. .

did you have the problem before the teardown to replace the 5th gear syn??

my car has always been hard to get in to 3rd when racing just have to be patient.

and my trans has also been rebuilt
bryant