Muncie experts --- mainshaft Q's

[Wayne M.]

Acquired a '68-'70 mainshaft, as identified by the 27-spline output, the hole for the nylon speedo drive gear retaining clip, and the depressions (2) drilled into the splines where the reverse gear slides.

My questions have to do with the latter. The '67 new product training booklet says "Muncie 4-speed passenger models incorporate anit-lash springs in the splined prortion of reverse GEAR" (caps are mine).

In pic 2 you can see the circular wire spring that protrudes into the matching spline zone of the reverse gear. The wire spring on the second (opposite) side of mine is missing (pic # 3). Where can I find this item in the parts catalog (Group and part number if possible). Are these the anti-lash springs referenced ?

A check of my parts books show the mainshaft number for '65-66 as # 3866927, changing to # 3890531 in 1967 (for the anti-lash feature ?) and then to #3910587 in '68 thru 1970 (hole for nylon speedo drive gear, I assume).

[Tom P.]

Re: Muncie experts --- mainshaft Q's

Wayne, read this carefully!!!!!!!!!!!!!!!!!!!
Take the one remaining anti-lash spring and throw it in the deepest river you can find and don't put them back in!!!!!!!!!!!!!!!
If you know your Muncies, then you know that those springs were discontinued after only a couple of years.
WHY?
Because reverse gear could/would eventually wear the spring down to the point that it would/could finally break, fall into the tranny case, circulate around and cause premature damage to the gears, bearings, syncros.
I've been building 4spds (mostly Muncies) for over 40yrs, and all the other Muncie experts that I visit with do the same thing.
Now, with that said, IF YOU JUST GOTTA have them, so that your Muncie will 110% NCRS correct (and God knows that NO ONE can ever see those springs), I'll give you one. Please don't ask me why I have saved a few----------------------because I CANNOT provide any sane reason!!!!!

[Joe L.]

Re: Muncie experts --- mainshaft Q's

Acquired a '68-'70 mainshaft, as identified by the 27-spline output, the hole for the nylon speedo drive gear retaining clip, and the depressions (2) drilled into the splines where the reverse gear slides.

My questions have to do with the latter. The '67 new product training booklet says "Muncie 4-speed passenger models incorporate anit-lash springs in the splined prortion of reverse GEAR" (caps are mine).

In pic 2 you can see the circular wire spring that protrudes into the matching spline zone of the reverse gear. The wire spring on the second (opposite) side of mine is missing (pic # 3). Where can I find this item in the parts catalog (Group and part number if possible). Are these the anti-lash springs referenced ?

A check of my parts books show the mainshaft number for '65-66 as # 3866927, changing to # 3890531 in 1967 (for the anti-lash feature ?) and then to #3910587 in '68 thru 1970 (hole for nylon speedo drive gear, I assume).

Wayne----


The part number was GM #3890532 (group 4.419). It was discontinued in August, 1985. I don't think this part is essential.

[William C.]

Re: Muncie experts --- mainshaft Q's

I'm with Tom, They are in the MFTG category, and the last two letters are "toy Gadget"

[Wayne M.]

Re: Muncie experts --- mainshaft Q's

Tom, Joe, and Bill --- message received, loud & clear. Remaining anti-lash spring now removed and tagged.

I attach a blow-up pic showing the wear on the side where the reverse gear slides.

I hope those '67-up owners with average-to-high mileage "original, never-rebuilt " trannys are not going paranoid .

[Patrick H.]

Re: Muncie experts --- mainshaft Q's

I actually went and found one to put in my 71's transmission when I rebuilt it. Found a spring sitting in a core at a local "parts collector's" place.

No one could tell me what it was or if it was needed, so back in one went.

Patrick