Chevy Nova Forum banner

1 - 20 of 22 Posts

·
Registered
Joined
·
149 Posts
Discussion Starter #1
Thanks in advance for any assistance. I'm completely new to any kind of automotive work aside from swapping out the occasional part on my old '94 Ranger. I've never done any kind of transmission work so forgive me if my terminology is off.

I'm swapping out a broken shifter for a hurst and new rods on an M21 Muncie in a '70 Nova. The only reason I feel even slightly confident doing this is because I found a fantastic video on youtube I'll link below. In the video the guy said it's good to put a plug in the unused (shifter mounting?) holes because sometimes they punch through and can be a source of leaks. I pulled the old shifter and plate off the transmission and found six threaded holes with no plugs. My question is what kind of plugs do I need? I called Advance hoping this was a universal thing, but he said I'd need to know the size and thread. I see no signs of leaking, but this was a new build when I bought it so it hasn't seen much road time in its current configuration.

I've googled "m21 transmission plugs", but I only get info on drain plugs.

This has ground me to a halt, but I'm hoping I can find out before I leave work so I can grab some on the way home.

Thanks

https://youtu.be/yaQwPQTenMg
 

·
Registered
Joined
·
301 Posts
If they aren't leaking, I wouldn't bother plugging them. If you feel you must, they are a standard thread size, I believe 3/8-16. Just take one of the old shifter plate bolts with you to the hardware store and buy some plugs with the same thread. The plugs will have an allen head. You can use rtv or blue threadlock or some other type thread sealant. I would avoid red thread lock since you don't want them permanently installed.
 

·
Registered
Joined
·
149 Posts
Discussion Starter #3
Thanks. I didn't even think of using the old bolts.

I'll seal them because I'm that guy. 100% the guy that if I don't seal them they will leak.

Thanks again.
 

·
Registered
Joined
·
149 Posts
Discussion Starter #6
I decided not to plug the holes, but that ended up not being what tied me up anyway. The plate for a hurst shifter on a Muncie transmission goes between the cross support and the transmission. I took out the bolts attaching the transmission to the cross support, jacked up the transmission just enough to get the plate under, lined up the holes and now I can't get the bolts started to save my life. I've tried both bolts in each hole. I'm afraid that little bit of lift from the plate has caused an alignment issue.

It really is a crappy design. The two bolts that go up through the bottom of the transmission are nested inside a small square tubing support. Hard to get fingers or tools to it.
 

·
Registered
Joined
·
149 Posts
Discussion Starter #7
Aaaaand I'm pretty sure I just cross threaded that first bolt into the bottom of the transmission.
 

·
Registered
Joined
·
149 Posts
Discussion Starter #8
Noooooo

Finally wised up and figured out I needed to move the crossbrace (?) to get to the two bolts in the bottom of the transmission. They weren't cross threaded, thank God. I think it was a combination of filthy bolts and the transmission was wanting to pull to one side putting the bolts in a bind. I finally got everything back together, got the rods on (that went so much smoother than expected). Crawled out from under the nova at 1:45 Sunday morning. Sat in the driver seat and... the shifter won't budge. I have no idea where to go from there. Can anyone make a suggestion?

Thanks.
 

·
Registered
Joined
·
20,051 Posts
Finally wised up and figured out I needed to move the crossbrace (?) to get to the two bolts in the bottom of the transmission. They weren't cross threaded, thank God. I think it was a combination of filthy bolts and the transmission was wanting to pull to one side putting the bolts in a bind. I finally got everything back together, got the rods on (that went so much smoother than expected). Crawled out from under the nova at 1:45 Sunday morning. Sat in the driver seat and... the shifter won't budge. I have no idea where to go from there. Can anyone make a suggestion?

Thanks.
Pull rods out of shifting arms on transmission. Make sure trans. is in neutral. Put transmission in neutral and usea drill bit, bolt, pin or whatever to lock shifter in neutral. Adjust rods as necessary to slide in shifting arms freely.
 

·
Registered
Joined
·
3,649 Posts
What sbc1320 said.

1.) Disconnect the rods from the tabs on the transmission side cover and reverse. Manually move them to make sure they go back and forth in to gear.

2.) Make sure all of the tabs are in "neutral" and you don't have any gears engaged.

3.) Use a drill bit to lock the tabs on the shifter itself into neutral, then readjust rod length and reattach side cover tabs.
 

·
Registered
Joined
·
149 Posts
Discussion Starter #11
I will double check these things, but I'm fairly positive I did all this correctly. The youtube video I found was very thorough. I clicked all the gears back and forth and back to neutral. Used a neutral alignment pin and spun the little piece on the rods until they lined up with holes on the shifter arms perfectly with no binding. I'll crawl back under as soon as I get home to reinvestigate.

Thanks.
 

·
Registered
Joined
·
3,649 Posts
I will double check these things, but I'm fairly positive I did all this correctly. The youtube video I found was very thorough. I clicked all the gears back and forth and back to neutral. Used a neutral alignment pin and spun the little piece on the rods until they lined up with holes on the shifter arms perfectly with no binding. I'll crawl back under as soon as I get home to reinvestigate.

Thanks.
Huh.

Well, if you can snap a pic under there (of the rods and shifter) maybe something will jump out at us. :D
 

·
Registered
Joined
·
149 Posts
Discussion Starter #14
I'm a liar. I do remember when I started clicking gears back and fourth the 3/4 gear didn't want to click all the way into 3rd or 4th. I could twist it, but it would only travel a little way in either direction and then spring back to the middle. It was about a week ago and I totally let it slip my mind.

Does that sound like a familiar problem to anyone? If so, does it sound like something a novice could fix? I feel like I did a good job with the shifter and rods, but I'm not sure how much more complicated I can go before I'm out of my depth.

That definitely sounds like a problem, but it isn't the cause of my shifter not moving is it? Seems like if 3/4 is stuck in neutral I should be able to slide the stick into 1/2 & R shouldn't I?
 

·
Registered
Joined
·
149 Posts
Discussion Starter #15
I'm a little late with pictures. I emailed the guy that made the video about why the 3/4 gear wouldn't click left and right. He suggested turning the transmission while trying to change the gear. No luck.

I did notice the stick isn't moving even when I change gears from below. That can't be right...
 

Attachments

·
Registered
Joined
·
74 Posts
Not sure what you're using for installation instructions but I used what Hurst offers on their web site for my Super Shifter/M21 application and what trouble I had was explained away within the same.
Don't panic! Your problem is likely in the trans, assuming you've got your shift dogs locked-up. Muncie's don't cotton well to "dry" shifting. They like spinning internals.
I'd suggest first removing the shifter's rods completely from the trans and make sure your trans will shift (spin your rear wheels while shifting. Takes two people unless you're The Flash!). If you can get all four, align it back in neutral and before your reconnect your shift rods using Hurst's instructions, make sure the shifter itself is not jammed somehow. Careful you don't move the shift arms on the trans when reinstalling the rods.
You'll get it. Just be patient and think about what your doing. It really isn't hard. I know because I did it and there's many experts on here behind us.
 

·
Registered
Joined
·
149 Posts
Discussion Starter #18
I surely do appreciate the input. Last night I jacked up the rear wheels and had someone hold in the clutch while I spun the drive shaft. It spun easily, but didn't seem to help at the time. I guess my bumbling around knocked something loose though. Walking by the car to workout just now I figured I'd give it one more try. It goes into every gear now. Go figure.

I do have to give it a little extra force (not an unreasonable amount) getting over to reverse while in the neutral groove. Is that by design?

Thanks again guys.
 

·
Registered
Joined
·
1,134 Posts
I do have to give it a little extra force (not an unreasonable amount) getting over to reverse while in the neutral groove. Is that by design?
Yes, there is a spring that needs to be compressed to get into the reverse gate.
It helps prevent accidentally getting into reverse.
 
1 - 20 of 22 Posts
Top