mucie m21 cracked housing

[Tom B.]

Brian,

Another possibility is a circut being completed "through" something other than, or in addition to, what the wiring should be connected to. It happens when you push/turn on the affected item. You need to observe your wiring behind the dash, around the steering column, under the hood at the horn relay, and around the horns. Check for loose wiring touching something other than a connector or possibly worn insulation exposing bare wire to a metal surface. Look for other wires that may be disconnected from something else also.

If your fuses would have been blowing then you would have been drawing too much current through them. That doesn't appear to be the case. One other procedure is to disconnect the wiring one by one from the affected components, until you can "localize" the problem. If you decide to do that then either have handy your AIM, a wiring diagram, or make good notes with pen, paper, and labels for the wires. If you have other thoughts or info post back. Tom #24014

[scott dixon]

mucie m21 cracked housing

i recently bought a trans for my 69. i noticed on the tailhousing, their is a crack on the boss where the shilter shaft goes in. it looks like some type of pin, probably 3 or 4mm dia. is sticking out of the boss on the casting. it is fractured across that area, and is leaking fluid. please excuse my vague terminology, as i know nothing about the proper names of these components. is this something that can repaired? or should the housing be replaced. how much should one of these cost if i do need to replace it?

[Joe L.]

Re: mucie m21 cracked housing

Scott------

First of all, Muncie tail shaft housings and side covers are a type of permanent mold aluminum casting which frequently have casting flash marks which look just like cracks. To look at one, you would think that the casting was cracked in numerous places, but this is usually just an "illusion". I have several Muncie NOS cast components still in the original GM box and all show this type of illusory cracks.

In your case, though, you may have a REAL crack. The pin that you refer to is a tapered steel pin which is used to retain the reverse shifter shaft. Very often folks will try to drive this pin out in the wrong direction and will crack the tailshaft housing. Also, folks may try to "seat" this pin on re-installation using too much force, also resulting in a cracked housing. So, you're problem may well be a cracked housing, but I'd recommend that you check the reverse shifter shaft seal and the shaft, itself. If either are damaged or worn, a leak will result in this same area.

If the housing is cracked it can be repaired using Heli-Arc welding, the low temperature aluminum rod available from the Cecil Muggy Company, or, even, an epoxy-type repair like JB Weld.

The housing which you require, GM CASTING #3857584, is long-since GM discontinued. Good used ones sell for about $50-100. You might even pick one up cheaper at a swap meet. These housings were used on virtually all 1965-70 Muncie 4-speeds, not just those used on Corvettes.

[scott dixon]

Re: mucie m21 cracked housing

does this housing face any torsional twisting when mounted in the car. if so i would be alittle weary about the quick fix route. the reason i ask is, when i manually shift the lever, the crack in the housing opens up, and fluid dumps out. is replacing the this housing a involved job. or is it a real quick swap of internal parts. do any of the internals need to be pressed in. the trans is currently out of the car, but i have not opened it up to see what make it breath. what would be a fair discount back from the seller for this repair. the guy that sold this to me says he is willing to work with me. would 150.00 be a fair discount for parts and labor?

[Bill Clupper]

Re: mucie m21 cracked housing

Ther trans being out of the car is the hardest part, the tailhousing just bolts on, the biggest problem is sliding the reverse shifter lever back over the flange that it grips to make the thing shift. Once you have the tail off, you might as well go through the rest of the trans and replace thrust washers, synchronizer brass and the like unless thia has already been done. I can't speak to the money side of it, but if I bought a "used" trans, I'd figure on rebuilding it before use anyway and if I could get the seller to knock off $150 for a $50-100 part that has to be disassebled for the rebuild, I'd be very happy

[scott dixon]

Re: mucie m21 cracked housing

this trans was apparently rebuilt 18-20,000 miles ago. but then again alot can happen, in even the short period of time. maybe i will have the whole thing taken apart? thanks for the input.