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-   -   Grinds in 1st, but only after leaving it in neutral for a bit (https://67-72chevytrucks.com/vboard/showthread.php?t=623707)

trevarthan 04-04-2014 10:41 PM

Grinds in 1st, but only after leaving it in neutral for a bit
 
My 1971 C10 L6 three on the tree grinds in first, but only after leaving it in neutral for a bit. For example, during normal driving, 2nd to 1st is fine. But if I sit at a stop light for a while in neutral with the clutch relaxed, I have to count slowly to five or else it will grind going into 1st.

What's going on?

Clutch dragging?

Thanks!

88Ironduke 04-04-2014 10:57 PM

Re: Grinds in 1st, but only after leaving it in neutral for a bit
 
The clutch may need a slight adjustment. But I believe the Saginaw three speeds did not have a synchronized first gear. Please correct if I am wrong here. I know my 3OTT will grind if not allowed to kind of "spool down" the rotating bits and pieces. I also swapped out my shifter bushings and that helped clean up the feel of the column. There is an awesome post on properly rigging the shift assemblies.

88Ironduke

trevarthan 04-05-2014 01:05 PM

Re: Grinds in 1st, but only after leaving it in neutral for a bit
 
Downshifting from 2nd to 1st is never a problem. I don't think that would be the case if 1st wasn't synchronized.

geezer#99 04-05-2014 01:17 PM

Re: Grinds in 1st, but only after leaving it in neutral for a bit
 
Just blip the throttle before you try to slip it into first. That'll speed up the input shaft, push the clutch in and slip it into gear.

GASoline71 04-05-2014 01:54 PM

Re: Grinds in 1st, but only after leaving it in neutral for a bit
 
Yup... Also known as "double clutching" or "Heel-toe" shifting. ^^^

Gary

imjeff 04-05-2014 02:21 PM

Re: Grinds in 1st, but only after leaving it in neutral for a bit
 
The syncros get worn over time as does the linkage. Just wait a bit longer after you push the clutch in so the transmission can stop spinning. Blipping the throttle won't help going from neutral to first.

jabborabbo 04-05-2014 02:48 PM

Re: Grinds in 1st, but only after leaving it in neutral for a bit
 
If I'm sitting at a light or wherever in neutral I just shift into second then shift into first before moving on...no grind that way.

geezer#99 04-05-2014 04:29 PM

Re: Grinds in 1st, but only after leaving it in neutral for a bit
 
Quote:

Originally Posted by imjeff (Post 6613298)
Blipping the throttle won't help going from neutral to first.

It sure will!
Have you ever driven a totally non-synchro tranny. AKA a crashbox. You need to match the engine speed to the gear speed to shift.
Afterall the clutch is only needed to get moving no matter what manual tranny you use. After that you only need the right rpm to shift up and down.

imjeff 04-05-2014 04:41 PM

Re: Grinds in 1st, but only after leaving it in neutral for a bit
 
Quote:

Originally Posted by geezer#99 (Post 6613473)
It sure will!
Have you ever driven a totally non-synchro tranny. AKA a crashbox. You need to match the engine speed to the gear speed to shift.
Afterall the clutch is only needed to get moving no matter what manual tranny you use. After that you only need the right rpm to shift up and down.

That works for DOWNSHIFTING. I have driven many, many non-synchro transmissions. I rarely use a clutch when shifting and am fully aware of how to match engine and transmissions speed. When a trans output shaft is spinning at 0 rpm and you "blip" the throttle from 800 to 2000 rpm, how does that match their speed? When downshifting the method you describe works. The poster is talking about starting from a dead stop in neutral. The grinding is caused by the transmission cluster spinning while a gear is being engaged. The clutch disconnects the trans from the engine so the cluster stops and a gear can be selected while stopped.

special-K 04-05-2014 10:12 PM

Re: Grinds in 1st, but only after leaving it in neutral for a bit
 
Quote:

Originally Posted by jabborabbo (Post 6613330)
If I'm sitting at a light or wherever in neutral I just shift into second then shift into first before moving on...no grind that way.

That's what I do

slikside 04-05-2014 11:02 PM

Re: Grinds in 1st, but only after leaving it in neutral for a bit
 
Quote:

Originally Posted by jabborabbo (Post 6613330)
If I'm sitting at a light or wherever in neutral I just shift into second then shift into first before moving on...no grind that way.

Ditto. Works on just about any manual tranny I've ever driven. Imports too.

19673ontree 04-05-2014 11:17 PM

Re: Grinds in 1st, but only after leaving it in neutral for a bit
 
Quote:

Originally Posted by slikside (Post 6614085)
Ditto. Works on just about any manual tranny I've ever driven. Imports too.

X4 :metal:

trevarthan 04-06-2014 09:45 AM

Re: Grinds in 1st, but only after leaving it in neutral for a bit
 
Quote:

Originally Posted by imjeff (Post 6613488)
That works for DOWNSHIFTING. I have driven many, many non-synchro transmissions. I rarely use a clutch when shifting and am fully aware of how to match engine and transmissions speed. When a trans output shaft is spinning at 0 rpm and you "blip" the throttle from 800 to 2000 rpm, how does that match their speed? When downshifting the method you describe works. The poster is talking about starting from a dead stop in neutral. The grinding is caused by the transmission cluster spinning while a gear is being engaged. The clutch disconnects the trans from the engine so the cluster stops and a gear can be selected while stopped.

I'm going to try this and a few other things today and see what happens. I think he thinks spinning the transmission up in neutral will spin the gears up. I'm not sure if it will or not. I'll report.

19673ontree 04-06-2014 10:37 AM

Re: Grinds in 1st, but only after leaving it in neutral for a bit
 
Quote:

Originally Posted by trevarthan (Post 6614521)
I'm going to try this and a few other things today and see what happens. I think he thinks spinning the transmission up in neutral will spin the gears up. I'm not sure if it will or not. I'll report.

The idea of going from neutral to first is to STOP the gears not spin them thats what putting it up in second will do it will stop the gears spinning so you can get the first gears to mesh ,, I tried this on my 67 yesterday after reading you post and it is much easier if you go fr second ,,,,

trevarthan 04-06-2014 10:40 AM

Re: Grinds in 1st, but only after leaving it in neutral for a bit
 
Quote:

Originally Posted by 19673ontree (Post 6614585)
The idea of going from neutral to first is to STOP the gears not spin them thats what putting it up in second will do it will stop the gears spinning so you can get the first gears to mesh ,, I tried this on my 67 yesterday after reading you post and it is much easier if you go fr second ,,,,

Yeah, that makes sense. Thanks. Second to first it is then. Hopefully my shifter doesn't get stuck. :p

1971 cheburban 04-06-2014 11:01 AM

Re: Grinds in 1st, but only after leaving it in neutral for a bit
 
Wow, from a 3OTT question to driving an eaton fuller 13 all in one post

trevarthan 04-06-2014 11:38 AM

Re: Grinds in 1st, but only after leaving it in neutral for a bit
 
Quote:

Originally Posted by 1971 cheburban (Post 6614628)
Wow, from a 3OTT question to driving an eaton fuller 13 all in one post

No clue what you're talking about. The three on the tree shifters have bushings that wear over time. When I bought mine, it was getting stuck between 1st and 2nd quite a bit. I took it to a mechanic near where I bought it and he lubricated everything. So far I haven't had a problem since, but I feel like I'm waiting for someone to smack me over the head with a 2x4. I keep a wrench in the glove box just in case.

It's an unrelated issue, except that if I have to hit 2nd first, then hit 1st, from a stop light under pressure of the cars behind me, I'm more likely to bind it again. Fingers crossed.

jabborabbo 04-06-2014 12:47 PM

Re: Grinds in 1st, but only after leaving it in neutral for a bit
 
Quote:

Originally Posted by trevarthan (Post 6614706)
No clue what you're talking about. The three on the tree shifters have bushings that wear over time. When I bought mine, it was getting stuck between 1st and 2nd quite a bit. I took it to a mechanic near where I bought it and he lubricated everything. So far I haven't had a problem since, but I feel like I'm waiting for someone to smack me over the head with a 2x4. I keep a wrench in the glove box just in case.

It's an unrelated issue, except that if I have to hit 2nd first, then hit 1st, from a stop light under pressure of the cars behind me, I'm more likely to bind it again. Fingers crossed.

It was binding as you went from 2nd to 1st?

trevarthan 04-06-2014 02:08 PM

Re: Grinds in 1st, but only after leaving it in neutral for a bit
 
Quote:

Originally Posted by jabborabbo (Post 6614804)
It was binding as you went from 2nd to 1st?

Yes. Actually, I just taught my partner to drive the truck, and she found out real quick that it still sticks if you shift too quickly. Then, just to add insult to injury, I got it stuck myself coming back from Autozone just now. I'd love to figure out how to fix that problem for good. It's pretty damn annoying.

luvbowties 04-06-2014 10:37 PM

Re: Grinds in 1st, but only after leaving it in neutral for a bit
 
Quote:

Originally Posted by trevarthan (Post 6614923)
Yes. Actually, I just taught my partner to drive the truck, and she found out real quick that it still sticks if you shift too quickly. Then, just to add insult to injury, I got it stuck myself coming back from Autozone just now. I'd love to figure out how to fix that problem for good. It's pretty damn annoying.

To avoid the hangup you are describing, when going from 1st to 2nd, move shift-lever a tad further "towards reverse" before letting it down to move on into 2nd. IE, accentuate the "H" pattern during 1-2 shift. After all, an "H" pattern is what it was designed for; but over time we tried to 'shorten' it into a more triangular shift--causing excessive wear on a wrong part:the gear-selector lug.

Also, to cure original problem you mentioned, you can shift into 2nd OR 3rd before going to 1st--either eliminates the grinding when finally going into 1st gear. Sometimes(and JUST sometimes), adjusting the clutch will help.
Sam


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