1972 C10 2wd M20 wont go into gear
 

Hello. Working on maintaining a 72 c10 we pulled from a field last summer. All has been good. Redid brakes, lines and all. Now the truck will not go into gear. Seems to be stuck in neutral. With or without clutch it will not go into gear. Pulled shifter up and out and it seem,s to be fine.

Has lube/oil/grease on it and does not seem to be broken. Can place back into top of tranny without a problem.

Have not pulled inspection cover as we have to pull that crossmember it seems. Which means grind down all of those rivets.

Any hints, tips tricks to try before we do all of that? Side of tranny is so covered in oil,grease and dirt it will take a week to get to the bolts.

help?
Larry

Re: 1972 C10 2wd M20 wont go into gear
 

Leave it shut off, clutch engaged and try it in each gear while trying to push the truck back and forth.

Re: 1972 C10 2wd M20 wont go into gear
 

This. ^

Re: 1972 C10 2wd M20 wont go into gear
 

Ok. Tried that. Nuthin.
What would have meant if it did go into gear?
What does it mean that it did not?

It broke down and he could not get into gear going down the road. Maybe 30 mph.
So neutral it was and coasted into parking lot.

Re: 1972 C10 2wd M20 wont go into gear
 

Sometimes rocking it and trying to force it into gear lets it pop back in to place.
I guess you’ll need to dig deeper.

Re: 1972 C10 2wd M20 wont go into gear
 

It sounds like you have a SM465 not a Muncie M20

Re: 1972 C10 2wd M20 wont go into gear
 

It says m20 on glove box.
Could it be shot?
90k miles.

Re: 1972 C10 2wd M20 wont go into gear
 

M20 is the RPO.
Not the trans type.
I think you might need to pull it apart.

Re: 1972 C10 2wd M20 wont go into gear
 

Damn dangit dagnabbit.

Any tips or hints? Support engine with floor jack.
Grind, chisel, drill out rivets for crossmember.
Drop driveshaft.
Use tranny jack on tranny to lower.

Is that about it? Best way to deal with rivets?
Heard using a cut off wheel/angle air grinder to
X them and then is air chisel to chisel for 4 pie shaped pieces was not bad.

Re: 1972 C10 2wd M20 wont go into gear
 

You don’t need to remove the crossmember to pull the tranny.
You need to pull the shifter out, unbolt the tranny hump, pull the driveshaft, unbolt the tranny and slide it back and remove it. Removing the hump gives you lots of room to work and room to slide the tranny back.

I haven’t pulled one for years. Maybe captain fab or someone else can give you removal tips.

Re: 1972 C10 2wd M20 wont go into gear
 

read thru this...http://67-72chevytrucks.com/vboard/s...d.php?t=322025
make sure the shifter slots are correct...

Re: 1972 C10 2wd M20 wont go into gear
 

If it had shifted into gear(s) with the engine off, it would have indicated the problem is that the clutch wasn't releasing and the synchronizer was doing its job and preventing the gears engaging before they're meshed as to not grind.

Re: 1972 C10 2wd M20 wont go into gear
 

This. Easiest and real common. I have seem the shifter bend in side the tranny too.

Re: 1972 C10 2wd M465 wont go into gear
 

Ok. Will try and move that tonight. Will update then.

Tranny hump. To remove that, is to pull seat and flooring up, correct?

Re: 1972 C10 2wd M465 wont go into gear
 

Affeared so!
Couple q’s first.

Can you push the truck at all or does it not move at all?
What gear was it in when it had the original problem?

Re: 1972 C10 2wd M20 wont go into gear
 

I don't quite understand, does it go into gear with the engine off. Pull the inspection cover under the flywheel with the 4 bolts, have someone step on the clutch while you're under neath the flywheel and see if the clutch is loose from the flywheel. Sometimes the disc will rust to the flywheel, with the clutch pedal down stick a screwdriver between the disc and the flywheel. I've had this happen twice now and only takes couple minutes to fix.

Re: 1972 C10 2wd M20 wont go into gear
 

Yes it will move. Seems to be stuck in neutral.

Was going from 2 to 3 or 3 to 4. Not 100% sure.

Could not get into gear, so he eventually settled on neutral and coasted into a parking lot.

Not sure if i could get inspection cover off because of that crossmember. Once i get all the dirt uncaked and cleaned off, youre saying that i should be able to remove that insp. Cover?

Re: 1972 C10 2wd M20 wont go into gear
 

I suspect you think the cover near the crossmember is an inspection cover.
It’s not. It’s a cover for a pto if you need one.
You won’t see anything in there to help.
You might need to pull the top off the tranny.

Re: 1972 C10 2wd M20 wont go into gear
 

I was going off what peanutbutter had said about the flywheel inspection cover.

So, short of checking down shifter hole itself to see if all is lined up and well there, i need to pull the seat, hopefully unbolt the hump. Then unbolt tranny from engine and slide back to remove.

Sound correct? How heavy is this beast? Tranny jack needed?

Re: 1972 C10 2wd M20 wont go into gear
 

Pulling trans should be last resort, 465 is very heavy, do not try to pull without trans jack. Was this trans working when parked?

Re: 1972 C10 2wd M20 wont go into gear
 

Trans has been working almost daily since we pulled it out of a field last july. Did not check fluid level in it though. Has not given any problems until it stopped working while going down the road.

Has 90k miles on it

Re: 1972 C10 2wd M20 wont go into gear
 

I went back and read post #4 again, if this started with the other guy it still sounds like clutch is not releasing, tin flywheel cover will come off but is tight, donot try to remove cross member. This could be a throwout bearing issue.

Re: 1972 C10 2wd M20 wont go into gear
 

K. Will check the shifter slot and see what i can do to get the insp cover off to see what clutch is doing, or not doing

Re: 1972 C10 2wd M20 wont go into gear
 

OK, if its been working daily the disc is not rusted to flywheel, have someone step on clutch pedal and watch to see if clutch fork is moving back and forth in the bellhousing. I would still pull the tin cover and watch the action of the throwout bearing when you step on the clutch pedal. Are you in Colorado or other. If its throwout bearing issue you will still have to pull trans.

Re: 1972 C10 2wd M20 wont go into gear
 

Yeah. I am in Longmont. North of Denver east of the republic of Boulder.