t86 with od

The good news is that the tailshaft from any 63-66 Rambler big car OD unit will work. Bad news is they aren't all that easy to come by...  I assume you need the housing, not the actualy shaft inside??

Most important question is: is your car 6 cylinder or V8 powered?

I'm not a specialist concerning the AM manual trans overdrive transmissions but this 'T86' title throws me off...

Everybody calls these manual transmissions 'Borg Warner' + the alpha-numeric designation, such as 'Borg Warner T10' or 'Borg Warner T96' etc.

In your case, I'm thinking you mean either 'Borg Warner T96' -for the inline six cylinder powered cars, or 'Borg Warner T89' -for the V8 powered cars.

-easy visual identification between the two; the T96 is a smaller gearbox and will have a four bolt stamped steel top cover & the T89 is a larger gearbox and looks very similar to a T10 having a cast iron bolt on side cover.

...could be that your car has a 'T86' which would be a helical cut gear version of the 'T85', which is nevertheless very similar to the 'T89' but again I'm not too sure about the alpha numeric designations and all the inevitable minor distinguishing features.

I know of two 'old school' junkyards here in Texas that have a surprisingly decent selection of mid-sixties Rambler parts cars.

1) John's Auto Salvage in Seguin, Tx. (near San Antonio)

2) CTC Auto Ranch in Denton, Tx. (near Dallas)

Both junkyards have websites on the Internet. They are both somewhat 'proud' of their parts in my estimation; don't expect low prices.

I'm very familiar with John's Auto Salvage. (absolutely huge junkyard, featuring all US make cars from approximately 1930 to 1985! -it's like a museum of all the 'oldie but goodie' US 'all steel' cars = awesome just to 'take the tour' and go for a walk through the yard...) They don't have any AM Rambler V8 manual transmissions & I've never seen any 'other make' (such as Ford) T96 + OD transmissions laying around in the various bone yards/storage areas.

Picture album I made to show John's Auto Salvages' AM Rambler car selection:

https://goo.gl/photos/n6UxJYnwTvzHP4t28

I know John's has at least two of the 6 cylinder three speed T96 + OD units (complete) -one in the trunk of a '62 Rambler Classic and one not removed in a '67 Rebel station wagon. (neither one has Twin Stick gearshift option)

ie; If yours is a Twin Stick V8 car, this is worth mentioning, avoiding any further confusion.

...something tells me this concerns a T96 because the larger T89 units seem to be nearly indestructible...

Galvin's AMC Rambler Parts, also on the web, originally got started when Doug Galvin was able to purchase an all AMC junkyard near Sacramento, California (1979/80?)

Doug Galvin (and Benjamin, father and son) still own the junkyard but their website does not give much indication of the fact; they have a good supply of used parts. (Doug's personal collection includes a red original paint car of every model AMC made in 1965... -his favorite year)

You must call Doug Galvin on the phone; he does not like Email for all the spam. He's a great guy to talk to & especially to meet in person face to face. He loves to 'talk AMC' and has all the ancient/huge dealer books (part numbers and details galore!) Doug is truly a one-of-a-kind asset to our AMC hobby world and deserves much credit for all his hard work to have so many 'unobtainium' rare parts reproduced for our favorite cars.

Basically speaking, if Doug or Ben Galvin can't help you get parts for your Rambler... you're SOL! (good luck!)

 Is your car inline six or V8 powered?

The output shafts on all AMC OD units are short, just enough to mount a seal and driveshaft yoke. Most OD units are like that. The OD takes the place of the long output shaft of the standard trans. In the OD era the output shaft of the standard trans was so long to make up for the length of the OD unit, at least on torque tube cars, so the same torque tube could be used for both.