New clutch install, input shaft won't disengage

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EDIT: It works! Thanks for the reply B.W., I figured once I made a post, it would fix itself.

I ran the truck for about 30 minutes to get her to heat up, went through combos of in gear + clutch depressed, and in neutral with clutch active. I then let her cool down, and now she will shift gears with engine on and clutch in.

So I'm assuming just a tight pilot bushing clearance. I'm guessing it will get tightish again once warmed up, but at least I think I'll be ok just letting the bushing wear naturally.

I'm glad I didn't jump to conclusions and pull the transmission. It was REALLY hard to do by myself. lol. That SM420 is heavy, and my back ain't what it used to be.

Howdy all, I need some knowledge and experience shared with me!
1965 C30 w/ 230 ci and SM420 transmission.

Symptom: Can't go into gear when running. Goes into gear when not running. Took it for a drive, did the "clutch in, brake hard" test, and it killed the motor.

1. Did a new clutch install. I'm almost 100% certain my friction disc is on the right way, since it had a large spring hub section - which I pointed towards the trans (flatter side towards flywheel). The truck did sit for a few months before I managed to get the transmission back in.

2. When clutch is depressed (blocked down from the pedal), I have a good amount of visual clearance between the pressure plate, friction disc, and the flywheel. I'm able to spin the friction disc free, and see a gap between the friction disc and flywheel.

3. It wasn't too hard to push the transmission in once it was lined up, so I don't think there was an alignment issue (but I guess you never know).

4. The new pilot bushing I installed is an oil impregnated bronze bushing from oillite, ordered from Novak: PB-3901295, Bushing, pilot, GM Gen I-III (1955-2000) cranks to GM Saginaw Muncie & Jeep T86, T14 (1968-1971), T176, T4, T5, AX15 (1988-1991) transmissions. It fit on the end of the input shaft well from my dummy test, and the clutch fitment tool went into it ok.

I'm assuming this is a tight pilot bushing from installation maybe deforming it a bit? The pilot bushing was a pain to get in. I've read about people sanding some material off to give more clearance.

Since the input shaft is harder material than the bronze bushing, does anyone have a way to get the input shaft to spin inside the pilot bushing to see if it will wear in some? I'm assuming if leaving the transmission in gear, and depressing the clutch, that is what it is supposed to be doing?

Or since the clutch depressed to hard braking exercise resulted in the engine dying, does it seem more likely that the friction disc isn't fully disengaging when it is running? I'm really confused since it spins free with the truck off and clutch pedal pressed.

Thoughts, wisdom? Thanks!

[B. W.]

Can you crank the engine with it in gear & the clutch depressed? Does the truck sit there like it should or does it lurch forward?

If the clutch is properly adjusted (clearance between disc & flywheel/pressure plate, like you said) & it lurches forward, your input shaft is stuck in you pilot bushing.

If it cranks in gear OK, can you shift gears while sitting still & the engine running?

If it's hard/ impossible to shift then the pilot bushing may not be seated deep enough & is pushing on the shoulder of the input shaft. (once again, assuming proper clutch adjustment)

Oh, BTW - great pic!

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Originally Posted by B. W.

Can you crank the engine with it in gear & the clutch depressed? Does the truck sit there like it should or does it lurch forward?

If the clutch is properly adjusted (clearance between disc & flywheel/pressure plate, like you said) & it lurches forward, your input shaft is stuck in you pilot bushing.

If it cranks in gear OK, can you shift gears while sitting still & the engine running?

If it's hard/ impossible to shift then the pilot bushing may not be seated deep enough & is pushing on the shoulder of the input shaft. (once again, assuming proper clutch adjustment)

Oh, BTW - great pic!

Doesn't lurch, but wants to crawl a bit. It is easily overcome by the weight of the truck or the brakes, though. It cranks fine in gear, but I cannot shift while sitting still and the engine running.

As far as clutch adjustment, I adjusted it so the throwout bearing is just barely not touching the pressure plate when clutch is engaged, and then there is about 1-2" of pedal travel. As you can see from the picture, I am getting visual plate separation, and can slide a putty scraper/tool in there and it doesn't seem to get caught on anything.

The old pilot bushing wasn't 100% flush with the crank, and neither is the new one. It is hard/impossible to shift when running, that is an accurate statement. I can slam it into gear from neutral with the engine running, but can't get it back out.

So if it is the edge of the pilot bushing on the input shaft shoulder, I'm guessing the only recourse is to pull the trans and hit it with a bigger hammer? Or I guess I could grind off some of the extra material. I was hoping I could just run it with the trans in gear and the clutch depressed and it may wear the bushing...lol.

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It works! Thanks for the reply B.W., I figured once I made a post, it would fix itself.

I ran the truck for about 30 minutes to get her to heat up, went through combos of in gear + clutch depressed, and in neutral with clutch active. I then let her cool down, and now she will shift gears with engine on and clutch in.

So I'm assuming just a tight pilot bushing clearance. I'm guessing it will get tightish again once warmed up, but at least I think I'll be ok just letting the bushing wear naturally.

I'm glad I didn't jump to conclusions and pull the transmission. It was REALLY hard to do by myself. lol. That SM420 is heavy, and my back ain't what it used to be.

[geezer#99]

Is your throw out bearing matched to your pressure plate?
Short tob goes with a raised finger plate, long tob goes with a flat finger plate.

Easy test to see if it's just a tob adjustment and not a pilot bushing problem.
Adjust the tob so it's tight with no slack and then see if it disengages enough.

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Originally Posted by geezer#99

Is your throw out bearing matched to your pressure plate?
Short tob goes with a raised finger plate, long tob goes with a flat finger plate.

Easy test to see if it's just a tob adjustment and not a pilot bushing problem.
Adjust the tob so it's tight with no slack and then see if it disengages enough.

The TOB came with my clutch kit. I think the issue is resolved. I think it was just a tight pilot bushing clearance, and after letting it warm up/run for 30 minutes, and taking it around the block, and then letting it cool down, I can now shift while the vehicle is running.