Transmission grinding when shifting into first 1st gear help

[curlrider11]

Hey friends, question that I am trying to diagnose or at least probe some info for right now.

Here's the issue. 69 patrol. Original Engine runs strong, idles around 550 rpm, transmission shifts and runs smoothly while driving in gears. Clutch engages disengages fine. The exception is when I'm at a dead stop in neutral and want to shift into first gear. I press in the clutch and try to shift into first and the tranny gear appears already to be spinning at a high rate where trying to mesh produces lots of whirring grinding before it can slow down enough to mesh.

It happens most of the time. And I don't want to just keep the clutch depressed at a stoplight and wear out the throw out bearing, unless that's a good sign that it's already happened. Any insight as to what might be causing this or any similar experiences? Read this forum below and not sure if it's the same deal, and haven't taken my transmission cover off yet to see how the clutch plate is doing.

No loss of power in drivetrain at all, haven't yet tried to shift from neutral into 2nd from a dead stop to see if it's in that gear as well or just first that's hard to mesh. Any thoughts would be helpful.

viewtopic.php?f=4&t=4172&p=32656&hilit=Shifting+into+first#p32656

A little more info and wonderings: could my rpm be too high at idle? New clutch master was installed recently and bled correctly, good pressure into slave from my inspection and feel anyway.

Is this something that's generally common with patrols and just takes getting used to....haven't ever driven another to compare.

[Esteban]

Hey friends, question that I am trying to diagnose or at least probe some info for right now.

Here's the issue. 69 patrol. Original Engine runs strong, idles around 550 rpm, transmission shifts and runs smoothly while driving in gears. Clutch engages disengages fine. The exception is when I'm at a dead stop in neutral and want to shift into first gear. I press in the clutch and try to shift into first and the tranny gear appears already to be spinning at a high rate where trying to mesh produces lots of whirring grinding before it can slow down enough to mesh.

It happens most of the time. And I don't want to just keep the clutch depressed at a stoplight and wear out the throw out bearing, unless that's a good sign that it's already happened. Any insight as to what might be causing this or any similar experiences? Read this forum below and not sure if it's the same deal, and haven't taken my transmission cover off yet to see how the clutch plate is doing.

No loss of power in drivetrain at all, haven't yet tried to shift from neutral into 2nd from a dead stop to see if it's in that gear as well or just first that's hard to mesh. Any thoughts would be helpful.

viewtopic.php?f=4&t=4172&p=32656&hilit=Shifting+into+first#p32656

By what you describe, it looks like the input shaft of the transmission is still spinning after you press the clutch at a stop. It could be that the clutch is not totally disengaging, like if you'll need to press the pedal further in. Try first to tweak the clutch regulation at the slave cylinder.

This is from the Service Manual regarding Adjustment of Release Bearing Play
1 . Remove return spring.
2. Loosen lock nut on push rod, and tum in push rod until there is no play.
3. From that position, turn out push rod 2.6 mm (0.102 in), and then tighten lock nut securely.
4. Install return spring.

If you try to shift from neutral into 2nd at a dead stop, the feeling will be totally different, since the synchro will play a part. It will effectively try to brake the rotating parts inside, in this case the input shaft (if it's in fact rotating). So it will feel like it goes smoothly when doing this in 2nd, compared with first or reverse (where no synchros are present and there's no way to stop the input shaft from rotating)

Has the clutch disk being replaced or relined recently?

The other post that you mention has very interesting material and all the problems some of the problems that member ctcruiser faced. But I guess you've ruled them out at this point.

[curlrider11]

Thanks Esteban, I don't think the clutch has been relined recently, and when I inspected it through The top cover it almost looked like it was slightly delaminating in some places and may need it in the near future. But I don't think that was the source of my problem. Maybe next time I'm in it I'll take a photo of what that clutch plate and friction material look like and you can help me judge. At least you gave me a starting point to go off of. I'll try that first and see if it's not quite set up right Thank you for the help. Will post an update sometime soon.

[Esteban]

Thanks Esteban, I don't think the clutch has been relined recently...

With the clutch, as the disk wears out you start loosing free play at the pedal, and constant pressure on the release bearing, like if you're stepping on the pedal constantly. Just the opposite of what you have, so we have to rule out the disk as a problem.

With a relined disk I have once a problem like you described before, with grinding noise at a stop when I tried to shift into 1st. The relining job was terrible and although once installed the disk thickness was like a new one, as soon as you stepped on the pedal, it sort of sponged out so it was constantly touching the flywheel and pressure plate, and never coming to a stop. Ended up installing a new one.

I bet that it will be something simple on yours.

[RiverPatrol]

When this issue occurs have you tried moving the shifter to any other gears, just to see if it could go there? I have a similar problem on one of mine, I believe it's the pilot bushing. There was a similar problem a user worked out, it was also the pilot bushing.

[curlrider11]

Haven't tried that yet but i will give it a go when I get home from work today. Thanks for the reply and test to run. Will update!

[curlrider11]

Two or three finds after closer inspection. Tranny fluid was "frothy". from my best guess i overfilled it when changing out fluids in the fall. (not sure this will remedy, but it's going to get replaced in the next week or so when i redo seals that are leaky in the transfer/tranny case. second thing i noticed is that I didn't install shims when replacing my clutch master cylinder, perhaps this is keeping the clutch from fully disengaging when i have it pressed all the way down. Will have to find adequate shims (because for some reason i tossed the stock ones, can't find them anywhere!), and then maybe re-bleed my clutch master because it's very dark even after doing it once already (wonder if that's a sign of a slave that's going out).

two or three things to start with and remedy.

[Esteban]

... second thing i noticed is that I didn't install shims when replacing my clutch master cylinder, perhaps this is keeping the clutch from fully disengaging when i have it pressed all the way down.

Could be! The lack of shims will cause the master cylinder to be pressed somehow, so the total travel is diminished once you press the pedal all the way.

You could put temporarily some regular flat washers of similar thickness and see how it goes. I don't know what the original thickness is, since I have a mechanical on mine.

[curlrider11]

Yeah good thinking, think i'll cut a few thick washers in half and see if they adequately can shim from the top and bottom. We'll see

[curlrider11]

When this issue occurs have you tried moving the shifter to any other gears, just to see if it could go there? I have a similar problem on one of mine, I believe it's the pilot bushing. There was a similar problem a user worked out, it was also the pilot bushing.

River, I tested out while on stands if I could shift from neutral into 2nd or 3rd. Those two gears had no grinding and we're just fine. It only happened in shifting to first or reverse. Wonder if that helps isolate.

Also, tried to see if shimming master cylinder would help in travel of cylinder, but it was already at full extension and had no need of travel further.

what might this issue only happening in first and not neutral to 2nd or 3rd be an indicator of? Still the pilot bearing?