C2andyP

I've had my 1966 C2 for about 9 months the car is really nice, but has always had a whine from 1 2 3rd gears anyway decided to get the trans out for a look...

On stripping the box looks in good shape, I sent some photo's to Paul Cangialosi and he was not unhappy with what he could see and a UK trans builder that I'm friends with also thinks the internals look good.

The only thing I've found is the oil slinger was missing from the input shaft so the gear driving the cluster must be running 40th forwards of the correct position, so the question is have I mound my problem or will this make no difference as far as whine is concerned.

Nowhere Man

It’s not a M22 with straight cut gears is it

C2andyP

No its a M20 so can't blame it on being a M22

Gavin65

Not trying to be a smart *** but it could have been rebuilt with straight cut gears, what did your rebuilder say.

C2andyP

No defo a M20, has the 2 groves in the cluster gear and the pictures of the M20 from Paul's book look exactly the same.

DZAUTO

M22 gears are NOT straight cut. They are just cut at a LESSER angle than M20 and M21 gears.
M22 gears



M20-M21 gears

C2andyP

There is no doubt my gears are M20, can we get back to the original question about the missing oil slinger being the cause of the whine as the input shaft is about 40th of the correct position.

Gavin65

I'm sorry but I honestly cant tell you if that could be the cause of it, hopefully one of the other forum members can help.

SWCDuke

It's probably normal. In the first three gears, torque is transmitted to the countershaft and back to the mainshaft by two sets of helical gears. The load creates some whine in all cars equipped with these BW/Muncie transmissions and most cars exhibit some gear whine in the intermediate gears.

Fourth gear is direct drive, so the gears are not loaded and there is no whine.

If the bearings are spalling the whine will get progressively louder.

The best way to determine if the amount of trans noise you have is normal or abnormal is to compare it with another Corvette with the same transmission.

If you recall the old "Moss" gearbox used in early XK-Es and other Jaguars, the non-synchro first gear had a very loud whine. I believe it is a spur gear, which his why it is so loud. Helical gears generate less noise, but can't carry as much load. The reason why the M-22 is louder than other related four-speeds is that the gears have a lower helix angle that makes them more durable and more amenable to heavy duty service, but louder.

Similarly, reverse gear in BW/Muncie four-speeds has a very loud whine because they are also spur gears, but you have to get up some rearward speed to hear it. My SWC with its CR T-10 and 3.08 axle can do over 70 MPH in reverse, but I've only have it up to 25-30 in reverse, and it really whines accelerating up to that speed.

Duke

Frankie the Fink

I will just say it took me a while to get used to the noises from my 63 very early Muncie, since it was my first C2...the sound just seems to transfer into the cockpit from the tunnel and jack storage area more than I expected.... And in reverse it whines like a mashed cat.

I don't think twice about it now....

DZAUTO

NOTHING sounds like a Harley.
NOTHING sounds like a radial airplane engine.
NOTHING sounds like a healthy BB.
And NOTHING sounds like an M22-----------------I love 'um!

I bought an M22 gear set for the Chevelle and built my own.
Next is an M22 gear set for the 56, and then for my 51 Chevy.

C2andyP

Yes I'm now thinking the box is not far from normal sounding but I'm enjoying the rebuild, and finding out about the Muncie trans so not all bad. So any more comments on how audible guys trans are?

Nowhere Man

Anther thing do you have the correct oil and is it where it needs to be

MelWff

you may also want to consider the effect of the gear oil viscosity on the noise. I assume you have no way of knowing what was in the box or how old?

C2andyP

Well I did check the oil level b4 I started, the guy had the car for 4 years prior to me and he kept a record of all the work he did, that included checking trans oil and topping up every year but no oil change so could be quite old. What oil would you guys recommend when I refill it?

Dan Hampton

My guess is that the main input bearing might be the culprit. Side loading on the other gears with the whine and, then, no whine in 4th would make me suspicious of that bearing. Since you have it disassembled, it would take but five minutes to replace it. You never know where some of these rebuilders get their kits. That is why you can't go wrong with D & L. Just for grins, if you have the input shaft out, spin with your hand and observe if there is any noise or drag.

C2andyP

I think the box looks like its been apart not so long ago, all the bearings look and feel great to me. I have the rebuild kit coming from 5 speeds on Tuesday so I'm hoping its a little better after that, if not I will assume its normal until I find out different at the summer shows coming up.

C2andyP

Forgot to say I also have a 1964.5 Mustang with the auto trans, this is so quite and smooth but its a different car I suppose, the Vette is so much better overall.

Frankie the Fink

That's no doubt the C4 transmission - there is really no comparison there..

DansYellow66

From my understanding, Muncie never installed an oil slinger in their original production - or if they did, it was later in time. And the slinger is often not included in standard rebuild kits and left out on a rebuild. But it's recommended that one should be installed during rebuilding along with a shim. That should put your play in an acceptable range.

Kind of doubt it will cure the whine - but stranger things have happened. Play on Muncie input shafts is not particularly tight or critical any way - you don't want to get it too tight. More likely just standard lower gear whine or possibly a bearing breaking down.