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My 3 on the tree is acting up!
#1374634 Mon Aug 24 2020 04:08 AM
Joined: Jun 2008
Posts: 1,453
S
Shop Shark
So lately when I shift into 2nd the gears grind a bit, and it’s worse if I push the shifter higher. I thought that was really weird. Then, not every time but often, when I push and hold the clutch pedal down and coast the gears grind lightly like if they’re barely touching. Not a horrible crunching sound. When I put it in neutral the sound goes away. Lastly, after I first start up and have waited to warm the engine then depress the clutch pedal and wait 4-5 seconds then try to put it in reverse the gears grind a little. Thought depressing the clutch pedal would stop those gears from freewheeling??? Not lately.

Can anyone tell me what’s wrong with my little 3-speed tranny? Thanks


Chuck
1950 Chevy 1/2 ton (original)
1951 Chevy 1/2 ton (future streetrod)
1941 Chevy coupe
1938 Chevy coupe streetrod
Re: My 3 on the tree is acting up!
Spotbiltxo #1374637 Mon Aug 24 2020 06:39 AM
Joined: Oct 2018
Posts: 67
C
Wrench Fetcher
When you say grinding on the shift to 2nd gear, do you mean during the shift - like the gears are having trouble engaging, right ? Not sure what you mean by the sound gets worse when you push the shifter higher. Do you mean that the transmission is in second gear, it is making noise, and if you push up on the shifter the noise gets worse?

Skipping to the bottom of the post, gear grinding when initially trying to shift out of neutral (especially into unsynchronized gears like reverse) is a classic clutch not fully disengaging issue. In other words, the clutch driven disc is still spinning and turning the transmission input gear when it should be almost stationary.

You did not really hit on any of the basics in your post, so at the risk of sounding like Captain Obvious, is the clutch adjusted correctly ? How much pedal free play is there ? (Distance pedal moves from top of travel to when you first feel resistance when pushing down on the pedal.) If you have a lot of free play, pushing the pedal down may not be fully disengaging the clutch. How about fluid ? Level OK ? Has it been changed recently ? If not, what is its condition ? You should also make sure the shift linkage is adjusted correctly, and does not have a bunch of slop in it (like many often do). I used to drive a 68 C-10, and when shifting into 2nd, you had to move the lever nearly into reverse before you could reach the gate and move the lever forward.

Another possibility is the pilot bearing. Instead of acting like a bearing and allowing the input shaft to rotate freely and independently of the crankshaft when the clutch is disengaged, it is applying friction, and acting more like a miniature clutch.

This may account for the noise you hear when coasting. With the transmission in gear, the driveline is spinning the clutch disc while the engine is near idle, so the pilot bearing is managing a significant speed differential between the transmission input shaft and the engine crankshaft. This goes away, once you shift into neutral.

With the vehicle stationary, clutch disengaged, engine idling, transmission in gear, do you hear a whining or growling noise coming from the clutch area?

The one good thing about manual transmission issues is that since you get to pick what and when is going on, it is a little easier to isolate faults.

Best Regards...

Re: My 3 on the tree is acting up!
Spotbiltxo #1374725 Mon Aug 24 2020 10:49 PM
Joined: Jun 2008
Posts: 1,453
S
Shop Shark
Bob, thanks for taking time to reply. Sorry I wasn't as clear as I thought I was being when I described my problem. I'll try to give some more detail...……

1. Yes, when I'm shifting from 1st to 2nd, at the top of the shift it grinds just a bit like while it's trying to engage. If I push the shift lever up even higher it grinds worse. Obviously I've got the clutch pedal engaged while I'm doing this.

2. This transmission was installed 3 years ago by a professional transmission shop. Got it from an elderly gentleman in our Inliners International car club. He said he had rebuilt it and it was ready to go, but I never asked what he had to do to it. It was stiff at first, but has loosened up and has run normally the last couple of years with no problems. These noises just started a couple of weeks ago.

3. The clutch has about 3-5" of travel before I feel the clutch disengage. It doesn't have to travel very much, and it feels solid. Aside from some chatter due to the old 216 leaking oil onto the clutch face, the clutch performs as it should.

4. I have not checked the fluid in the transmission. Guess that's something I should have done. I'll look at it this evening when it cools off and will report. I assumed it was filled correctly when the transmission shop installed it.

5. My shifter linkage has always given me trouble. I've read about rebuilding the shifter box on the steering column so that the pawls are welded up and ground square again, but I don't weld and just live with it. I've gotten good at jumping out and aligning the shifter links at a red light and that fixes the problem. The rods from the tranny to the shifter aren't terribly sloppy, but probably could use adjusting. I'll try doing that this weekend. Otherwise, it's always shifted easily and has engaged 2nd and 3rd without any grinding noises.

6. "With the vehicle stationary, clutch disengaged, engine idling, transmission in gear, do you hear a whining or growling noise coming from the clutch area?" NO. Perfectly quiet.

The pilot bearing you describe might be the problem. I knew I had a problem the first time I heard it grinding when the clutch pedal was depressed and I was coasting about to turn into my driveway. I knew that wasn't a normal sound! If that's the cause, or part of it, then I'll have to take it back to the shop for repair. I've never worked on a transmission before, so I'm a novice in that department!

Thanks!


Chuck
1950 Chevy 1/2 ton (original)
1951 Chevy 1/2 ton (future streetrod)
1941 Chevy coupe
1938 Chevy coupe streetrod
Re: My 3 on the tree is acting up!
Spotbiltxo #1374748 Tue Aug 25 2020 01:20 AM
Joined: Jan 2013
Posts: 1,809
Shop Shark
Chuck,

We can drop your trans in no time at all. It is very easy. We can also look at your linkage and do the proper adjustments for shifting. My guess is that you might need a new box. I have that part number if you want it.

Btw, we still need to link up to work on your visor and all!

Chris

Re: My 3 on the tree is acting up!
Spotbiltxo #1374760 Tue Aug 25 2020 03:49 AM
Joined: Mar 2010
Posts: 9,446
5
Master Gabster
Try adjusting your clutch free play. You push the pedal with your thumb. You should feel 1/2 to 1 inch of free play before it gets harder to press the pedal further. Do you have a Chevrolet Factory manual?

Re: My 3 on the tree is acting up!
Spotbiltxo #1374767 Tue Aug 25 2020 05:52 AM
Joined: Oct 2018
Posts: 67
C
Wrench Fetcher
Quote
Yes, when I'm shifting from 1st to 2nd, at the top of the shift it grinds just a bit like while it's trying to engage. If I push the shift lever up even higher it grinds worse. Obviously I've got the clutch pedal engaged while I'm doing this.

That is interesting. Once the gear is engaged, it's engaged. Is it possible that pushing hard on the shift lever is causing the linkage to try and drag another gear into engagement? I did not think this could happen, as there is typically an interlock mechanism in the trans to prevent this from taking place.

Quote
The clutch has about 3-5" of travel before I feel the clutch disengage

As 52Carl says, try checking/adjusting the pedal free play. The "thumb" test that he mentions is an excellent method. I might add that you can hold a ruler next to the pedal with one end against the floor in order to get an accurate travel measurement. What you are actually measuring is the distance that the pedal moves in order to push the throw out bearing from its normal resting position to the point where it first contacts the pressure plate diaphragm spring (or fingers if it's not a diaphragm type pressure plate).

Once free play is established, you'll have a better understanding of how much pedal travel is left to actually release the clutch. If free play is excessive, the clutch pedal uses up most of its travel moving the throw out bearing, and does not have enough left to fully disengage the clutch.

Also agree 100% that a service manual is invaluable here.

As for other causes of the clutch hanging up, there is another post about grinding while going into first. In it, klhansen also has a good suggestion about the driven disc hanging up on the input shaft splines. If it does, instead of floating between the flywheel and the pressure plate when the clutch is released, it rubs against the flywheel.

Quote
This transmission was installed 3 years ago by a professional transmission shop.
If your trans is only three years old, the lube is probably in good condition (although its still not a bad idea to check the level). While I doubt it has anything to do with this issue, I was just fishing for an answer like: "Not sure.. Think its the same stuff that's been in there since 1950" smile

Quote
With the vehicle stationary, clutch disengaged, engine idling, transmission in gear, do you hear a whining or growling noise coming from the clutch area?" NO. Perfectly quiet

Just to be 100% clear. I meant that under those conditions, with the pedal pushed down, you do not hear noise, right?

Quote
I've gotten good at jumping out and aligning the shifter links at a red light and that fixes the problem.

Oh Man! does that bring back memories! smile I had totally forgotten about that! I got my 68 from my Dad back in the late 70s. He always kept this yellow handled screw driver in the glove box for just such a situation. He left it in there for me when I took the truck over, and when I sold it to a buddy of mine at work, I bequeathed it to him. smile Too funny...

Re: My 3 on the tree is acting up!
Spotbiltxo #1374776 Tue Aug 25 2020 12:48 PM
Joined: Mar 2019
Posts: 1,035
G
Shop Shark
Fluid level as previously mentioned, wouldn't hurt to check. But it sounds like the clutch is on the way out to me. What u described as freeplay, sound likes it failing. And pretty soon you have no clutch at all.

Re: My 3 on the tree is acting up!
Spotbiltxo #1374782 Tue Aug 25 2020 02:02 PM
Joined: Sep 2009
Posts: 319
G
Shop Shark
The best fix I have found for the 3-speed column shift is an SM-420 smile


-Patrick
1953 Chevrolet 3100
261 / 4-speed / 4:11 / Commercial Red

Re: My 3 on the tree is acting up!
Spotbiltxo #1374802 Tue Aug 25 2020 05:40 PM
Joined: Dec 2015
Posts: 247
D
Unconventional Thinker
I will agree with changing the gear oil. I rebuilt mine about 5 years ago. It was sticky at first but then shifted better. I checked the oil level last night and it is black. That may be why is grinds into 3rd when it's up to operating temperature.


2007 Forester XT Limited (2nd Owner)
1991 Cherokee Laredo (2nd Owner)
1981 Chevy 3/4 Ton Fleetside 8,600 Camper Special (3rd Owner)
1965 Chevy 3/4 Ton Fleetside (3rd Owner)
Re: My 3 on the tree is acting up!
Spotbiltxo #1374931 Wed Aug 26 2020 05:03 PM
Joined: Jul 2019
Posts: 329
B
Shop Shark
If your jumping out to free up jammed linkage its incorrectly adjusted and trying to jam itself into 2 gears at once or goin to the next gear while still engaged with the previous. I got pretty good at getting my adjusted dead nutz on even after adding 20 extra bends into my shift rods and building my own pivot for the relay rod setup. It should shift like butter when correct. When you pull up and down on the shifter in neutral you should feel no resistance in the shift box. If the 2 slots are not perfectly aligned your gonna always be fighting with it.

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