I have a 1976 vintage aluminum case 833-od. The case is tapped for a reverse switch, but in it's place was a steel plug with a spring and ball bearing. The plug looks to be a factory deal, and not a cobble to fill the void from where the switch is supposed to be. I'm not too familiar with 4 speeds, but what would be the reasoning for the trans "not" to have a reverse switch? Am I right in "ass'uming that I can remove the plug, and replace it with a reverse switch for my application?

The plug/spring/ball isn't the BU light switch opening, it's the Reverse lever detent ball housing.

The BU light switch opening is above that.

Thanks John. The smaller opening above the reverse lever detent ball housing also has a plug. I cant think of why there would be a plug and not a switch there.

maybe somebody had it in a car that was old enough not to have back up light so they felt like they needed to swap the switch for a plug to save an ounce or two of weight.

The plug (P/N 1139153) was used from '49 to '75 but I, too, find it strange for it to be in years after BU lights became standard in cars...maybe not in trucks.

The partial VIN stamped in the case might show a truck origin.

Thanks for the info John. I guess I was just more curious than anything else. Ironically the trans does have the clip to hold the bake up lamp wiring to the case. Now, any good tips to get the detent ball and plug back in the case? Guess I'm gonna have to open it up.