Muncie Tailhousing Questions

[Larry S.]

I have a couple questions about muncie tailhousings.

1. Are they all interchangeable or do I need to look for a certain part # to match my application? I believe 1967 used extension housing #3857584 but will other part #'s function?
2. What are some things to look for when buying one, ie common problems, wear points. stripped threads.etc.?
3. What is a resonable price to expect to pay.

Thanks
Larry

[Wayne M.]

Re: Muncie Tailhousing Questions

Larry --- yes, the ...584 is what you need for your 4-speed 1967 to function properly. The late '63 thru '64 ...429 has the speedo cable attachment on the wrong (driver) side, and the 1971-up ....764 is for a larger diameter 32-spline output shaft.

If you are missing the speedo "bullet" or the reverse shifter shaft, make sure the one you buy has these items. You may want to replace the output bushing and install a new output seal and shifter shaft seal.

I used to think $100 was the going price, but I see that some are selling for less, in the current economy.

P.S. I've seen two versions of the casting # font size on the "3857584 GM"; not sure what judges consider correct for what years

[Joe L.]

Re: Muncie Tailhousing Questions

Larry --- yes, the ...584 is what you need for your 4-speed 1967 to function properly. The late '63 thru '64 ...429 has the speedo cable attachment on the wrong (driver) side, and the 1971-up ....764 is for a larger diameter 32-spline output shaft.

If you are missing the speedo "bullet" or the reverse shifter shaft, make sure the one you buy has these items. You may want to replace the output bushing and install a new output seal and shifter shaft seal.

I used to think $100 was the going price, but I see that some are selling for less, in the current economy.

P.S. I've seen two versions of the casting # font size on the "3857584 GM"; not sure what judges consider correct for what years

Wayne and Larry-----


The fitting ("bullet") is still available from GM under GM #345215. It's not the original part number but it's virtually identical to the original. This includes a new seal.

The reverse shifter shaft and reverse shifter fork are another matter. They are long-since GM discontinued. For originality, you need the shifter shaft with external threads (used through 1968). You can use the 1969+ shaft, though, which has internal threads. These parts may be available in reproduction, though, if you need them. You can buy a complete NEW "Muncie" transmission these days assembled from new reproduction or replacement pieces so they must be getting these parts somewhere. Larry Fischer will know. You can even obtain NEW, '584'-equivalent extension housings but their configuration will not be the same as original.

I would always replace the extension housing bushing and seal. It's not worth taking a chance on used pieces of unknown serviceability.

The main problems with used extension housings:

1) reverse shifter shaft boss cracked by some klutz installing the retaining pin the wrong way or using too much force to install the pin;

2) reverse shifter shaft boss end "mashed" due to impact damage. This causes the seal to be impossible to install OR, if damage is minor, the seal will install but distort and leak;

3) cracks. Be cautious, though, as these are die castings and usually have NUMEROUS casting imperfections which appear just like cracks but are not cracks.