I purchased an all aluminum A-833 A body overdrive with a main case casting date of 6-30-77 at a flea market. The seller assumed it came out of a Feather Duster or DartLite.

The front of the main case has an open hole thru the case with a 1/4-18 NPT thread. The hole is about 2.5 inches from the expansion plug toward the cover side.

I will use a flush plug with sealer to close the hole however I wonder what would cause someone to go thru the bother of adding this?

A punch could be inserted to push a sticky reverse gear?

Any ideas?

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1965 Dart 110k, 225, Carter BBD Super Six, 2 1/4 single exh., sbp manual scarebird front disc, 7 1/4 rear 2.94 sure grip, 14 x 4.5 OEM wheels, 833 OD with hyd. throwout bearing, HEI, electric fan, ram air/heated air, Accusump. http://plymouthcarclub.com/

trying to visualize...by expansion plug do ypu mean the cup shaped plug that covers the countershaft? and then, is the drilled hole down from that on the face that bolts to the bellhousing?

rock
'64d100

Not with that late of a date, Volare/Aspen... A-bodies were dead by june/july of 1976 or so... (so casings would be dated 1975-1976)

That modification is a new one on me... I'm not sure why they'd do it... I did have a case that the threads in the reverse switch had been smoothed out, and they closed it up with a couple of marine plugs and let the reverse 'hammer' hit the head of the bolt holding them in...

Interesting.

-D.idiot

Expansion plug is the term used by the FSM for the plug that covers the countershaft insertion hole. The hole is on the same casing face as the expansion plug and inboard of the holes used to fasten the transmission to the bellhousing.

The newly added hole is at the same level as the expansion plug and goes into the case allowing fluid to liberally spill out if a pipe plug is not inserted. It appears to be in line with the reverse idler gear shaft

If something down in the lower part of the case had been previously jambed such as the reverse idler gear shaft maybe a rebuilder would drill the hole to insert a long punch to loosen it up and then tap the hole for the pipe plug?

The FSM suggests using a C-3638 tool to press out the reverse idler gear shaft which the rebuilder might not have had?

If so why didn't they finish the job by closing up the open hole by installing the plug?

The transmission appears to have new gears & the case is spotless on the inside & outside so some rebuilding may have occurred.

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1965 Dart 110k, 225, Carter BBD Super Six, 2 1/4 single exh., sbp manual scarebird front disc, 7 1/4 rear 2.94 sure grip, 14 x 4.5 OEM wheels, 833 OD with hyd. throwout bearing, HEI, electric fan, ram air/heated air, Accusump. http://plymouthcarclub.com/

Donpal,

Thanks for confirming...I know the plug is really called expansion plug, but folks here sometimes use a name like z-bar for something the Mopar FSM calls sumpin else. Just wanted to be sure of its location regardless of name. I have never had the tool to change the idler and neve needed it , so in the end don't see any reason to have made the hole, unless as you guess, someone not being able to get the idler out any other way thought that the hole would help. I wondered initially if it might not have been a crazy way to get in a tranny temp sender, but there are so many places to have done that other than the bellhousing face why pick the front!

A curiosity...
rock
64d100