[Kybird]

I have a Muncie 220 in a 67 firebird with a 406/RA4 cam/16 heads. The trans supposedly came out of a 69 bird along with original shifter. It feels solid, but will pop out of 2nd on heavy de-acceleration. Possible causes? How serious?

2nd trans question, long term, I was thinking of switching to a wide ratio and less rear gear (3.73 now). What is the trade value of 220 to a 256 muncie?

Thanks.

[Kybird]

I have a Muncie 220 in a 67 firebird with a 406/RA4 cam/16 heads. The trans supposedly came out of a 69 bird along with original shifter. It feels solid, but will pop out of 2nd on heavy de-acceleration. Possible causes? How serious?

2nd trans question, long term, I was thinking of switching to a wide ratio and less rear gear (3.73 now). What is the trade value of 220 to a 256 muncie?

Thanks.

[Blackcat]

Popping out of gear is a sign of worn syncros and the engaugment teeth on the gear.
I recomend rebuilding the Trans with the new Hook sliders. They are for that problem.

Usually I'm found working on my Pontiac. If you want to find me Look for the white picket fence and all the old Pontiacs parked outside. And the half dissembled engine sprawled all over the driveway!

[mike nixon]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Ky Bird:
I have a Muncie 220 in a 67 firebird with a 406/RA4 cam/16 heads. The trans supposedly came out of a 69 bird along with original shifter. It feels solid, but will pop out of 2nd on heavy de-acceleration. Possible causes? How serious?

2nd trans question, long term, I was thinking of switching to a wide ratio and less rear gear (3.73 now). What is the trade value of 220 to a 256 muncie?

Thanks.<HR></BLOCKQUOTE>


if the trans is coming out of gear on decel it's possible there's a weak or broken detent spring in the cover asm. these springs help hold the forks in gear and when weak or broken will exhibit this problem.

normally when you get a gear rounded it'll pop out under power.

in my experience bad syncros will either shift extremely hard or won't go into gear at all.

if the trans ends up having to be rebuilt definitly have the hi-po syncros put in.

mike

[Skip Fix]

Another thing that did that on my old car did was first check tranny to bell housing bolts loose and it wil do that. Last thing a bad crank pilot bushing wil do that also- had that in my old 383 Roadrunner.

[RAM YAK II]

Had the same problem and found the shifter forks were worn and wouldn't let the gears mesh completely. Replaced them and everything was fine.

[RPM]

Any or all of the above. The Torque-lok sliders would help the problem but it sounds like a rebuild is in order anyway.

Before ripping the trans out check you shifter. Another cause of shifting problems/popping out of gear is a bad pilot bearing.

67 GTO winter project