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Clutch issue - grind in downshift from 2nd to 1st

Posted: Mon May 15, 2017 5:03 pm
by Arse
Hey everyone. Finally got the jeep driving this weekend after a few months of rehab. Rebuilt carb, fixed gas tank, new battery, rebuilt starter and generator, new brake system, new brake/Clutch cross arm, etc. She purrs like a kitten (Or big cat). Anyway, on her maiden ride, I noticed the gears grind when I try to downshift from 2nd to 1st. Can't get it into gear without forcing it (which I didn't do). I have little to no experience with clutches. She shifts fine on the way up, and ok from 3rd to 2nd, but won't go 2nd to 1st.

1952 m38

Any help will be appreciated.

Thanks,

Nick

Posted: Mon May 15, 2017 5:09 pm
by TGP
1st gear is non synchronized.
So when going from 2nd to 1st you have do rev the engine with the clutch
Out and trans. in neutral to a approx. RPM that the engine will be turning
Once you complete the shift and let the clutch out again.

Practice.
Also the faster your going the higher the rev. so keep it slow as not to over rev the engine.
Make sense?

Good Luck
Tom

Posted: Mon May 15, 2017 5:14 pm
by Arse
Makes sense. I'm new to the M jeeps. I've had a 74 cj5 for about 12 years and this is my first flatfender. I love it and have had such good time working on it.

Revving the engine seems to defeat the purpose of down shifting but I'll give it a try. Thanks for the help.

Posted: Mon May 15, 2017 5:16 pm
by oilleaker1
Most of us just come to a stop to engauge 1st. You can damage the gears and put metal into everything else. Just not worth it. Matching Engine RPM with gear rotation is something professional truck drivers take for granted. Me, I'm not one of those!!! 8)

Posted: Mon May 15, 2017 8:08 pm
by Arse
Well, I gave it a try tonight when I got home from work. Didn't work all that well for me. Couldnt match the rpms and clutch. Clearly I'm not a long haul truck driver, so I'll stick to stopping from 2nd haha

Thanks guys

Posted: Mon May 15, 2017 9:34 pm
by wesk
I started driving in the 50's. Just about every 3 speed manual had an un-synchronized 1st gear and a very wide range 2nd gear. We always stopped first then 1st gear.

To downshift manually to an un-synchronized 1st gear requires a flywheel RPM that matches the RPM of the tranny's input shaft. This takes a lot of experience and without that experience usually ends with big chips out of the 1st gear teeth. Hardly worth it in our jeeps.

Posted: Tue May 16, 2017 6:14 am
by skyjeep50
You might want to click on the "Downloads" section of this website. Inside you will find all the operator's, parts and maintenance manuals for your jeep. A thorough read will answer a lot of your questions.