Royce's and Ted's information pertaining to T-85 driveshaft yokes and trans. rear mounts is good, depending upon the year of the T-85.

That said, be careful that whatever T-85 you're looking at is out of a Ford or Mercury.  T-85s were used in a lot of other applications like Studebakers, Packards, and former Chrysler Corp. vehicles to name a few.  Check to make sure that the transmission main case bolt pattern is FoMoCo bellhousing type and that the input shaft is either 10 or 23 spline.

Royce's point regarding the trans. output shaft is particularly true for the '55, '56, and '57 FoMoCo spline count of 16.  I'm told that this Spicer yoke has been out of production for years.  The saving grace IF you do need one of these yokes is to find a '55, '56, or '57 Merc with a driveshaft in it.  Whether the trans is a T-85  3 speed, 3 spd. w/ od OR a Merc-O-Matic (yes, a Mercury auto trans.) the driveshaft yoke is the same!

The later Ford T-85s, '58(?) into the early '60s passenger cars used a 31 spline tailshaft.  These yokes are easier to find and may be the same as some FoMoCo automatics.  -I don't know my post '57 Fords well enough to say. 

Another interesting thing regarding the T-85s is that they are a look-alike for a T-89.  Both have 9 bolt curved side-covers as Dan described.  Both have side covers that have casting marks including the I.D. of T-89!  The internal difference is that the main shaft in the T-85 has a helical spline while the T-89 has a main shaft with a straight spline.  I've been told that T-89s were commonly used in Ford trucks...

FoMoCo T-85s and T-89s with overdrive used the Borg Warner R-11 overdrive units that had 4 gear planetary units.  The T-86s you asked about used Borg Warner R-10 overdrive units that had 3 gear planetary units. 

The T-85s and T-89s are RUGGED transmissions.  Neither has a synchronized 1st gear.  The R-11 overdrives are also a rugged unit.  I have run into R-10 and R-11 units where there have been problems with the planetary gear set or the overrunning clutch unit, but the problems I've seen have stemmed from failure to maintain lubricant levels.

These links will show you a picture of what the T-85 and T-89 trans. main shafts I've described look like.  -The pictures are borrowed from eBay.

T-89 straight spline trans. main shaft
http://www.ebay.com/itm/281690647918?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

T-85 helical spline trans. main shaft
http://www.ebay.com/itm/331469112457?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Hope this helps. 


NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York

What mod did you have to do to the crossmember Ted? I assume you had to move the mount back?

Durham Missouri

If you get a T-85 make sure it comes with the tail shaft yoke.. They are very difficult to find

My ’55 Ford Customline originally had the T86 overdrive and I swapped it over to a T85 overdrive tranny in about 1990.  The T85 physically fit the ’55 tunnel without any problems but I did have to modify the transmission crossmember for the relocated transmission mount and change up the driveshaft due to the different u-joint requirement.

Lorena, Texas (South of Waco)

The one I am looking to buy is an overdrive. I am just trying to minimize any surprises when doing the engine/trans swap.

Durham Missouri

I use a T85 with OD behind my Y in my 57. My T85 was from a 61 390/401hp Galaxie. Had to change clutch disc to a 23 spline and the yoke on the drive shaft, I think the bigger output shaft on the T85 is the same size and spline as a C6..

You might consider a T85 with Overdrive.  Its a 30% reduction in RPMs 

The T86 is a top load trans case from my understanding. The T85 is sideload, and the bottom of the cover plate is CURVED as opposed to the other mid fifties ford transmissions being a pretty square rectangle. Google images for T85's and see what you come up with.

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

How can you tell one from the other from the outside?

The T85 is physically bigger (and heavier) than the T86. The T86 is a light duty trans for 6 cyl and small V8 applications. The T85 is much stouter and was found behind engines up to 406 cubes in FOMOCO applications. The T85 should fit your trans tunnel with no mods needed to the tunnel/firewall. Your linkage should also work with it.