T85 - non OD to OD?

I have a T85 borg warner trans. Is it possible to convert it to overdrive using an OD unit from another trans? If it can be done, does it have to be from a T85?

 

Better off getting a T-85 od or 86 OD ( think 86 is the same bolt pattern,,all the stuff you'd have to change ,,would be like buying a whole trans anyway

 

The T86 is not nearly adequate for a small V8. They barely were good enough for a six.
They held up reasonably well behind the Rambler sixes, but not any Stude V8.

I used to strip the teeth off the gears all the time even back when they were plentiful, not very old, and easy to get from low mileage crashed cars. Stude should not have put them behind V8's.

The T85 is a cousin to the t-something was it T89? that Chevy used a lot. Same basic case, and internal gears, but with Chevy mounting ears, and shorter Chevy input. You may be able to use most of those parts for repairs. They usually hold up well behind a V8 unless you are a hot rodder. They are very hard to find with a Stude pattern or with an overdrive.

The Overdrive is a different matter. There is a shift rail or rather a "lockout rod" that needs to pass thru all three sections of the cases.
If you don't have the close-tolerance bores all lined up perfectly (I think they had dowel pins lining up the cases) the rod will bind.
It is needed, if I remember back that many years, to lock out the freewheeling feature to allow you to back up in reverse.

I have no idea whether or not that bored rod-passage is machined into the non o.d. front gear cases. If it isn't there, you have a real project on your hands drilling it, reaming it, and making everything line up just perfectly to avoid binding the rod.

 

I found a Stude truck V8 T85 overdrive. Problem solved.

 

Also, the T85 used a bigger R11 overdrive. Nearly everything else used the R10...any way you cut it, you'll need to find a T-85 with OD and use most of it to convert what you have!

 

If you are going for the OD , get the trans with the OD on it . too much trouble finding all the parts to make one .
You could just get an adapter and a T-5 !

RetroJim

 

I don't think there was a bigger BW OD unit -- all were the same... at least all I've ever seen. Rambler used a T-86 behind a 232 six and a 287 V-8. The T-89 is a much stouter transmission and was used behind the Rambler 327 and a lot of other big cars. Those are both three speeds. The T-10 four speed is a T-89 with reverse replaced with fourth gear and reverse moved to the output shaft housing. The T-86/89/10 share the same bolt pattern.

I'm glad you found a trans with the OD unit. The trans main body and gearing inside is the same as a non-OD trans, as is the main case. The output shaft is special to fit inside the OD though -- special short length and splines. The 1" thick adapter between the OD unit and trans is unique to each transmission model also. So adapting one to a different trans is a chore! You could make a cover plate with a bearing and output shaft from an old trans and make a divorced mount unit with a slip joint between the car trans and OD unit. I've seen that done, but it makes the trans****embly kind of long and takes some machine work.

 

Trust me, the t85/r11 od unit is bigger than the r10 model that the t86 and t96 used.

The t85 has a r11 instead of a r10 attached to it, which has 4 sun gears instead of 3, and is just bigger in about every way.

Back in the day the t85 and t/85 od was put behind 289 supercharged Studes, 312 supercharged fords, 413 mopars, 352 packards, etc. Not many cars had them, and they are hard to find! The ultimate 3 speed? Cars switched to 4 speeds before they made them any stronger than this one!

 

So I learn something!! The R-10 was used so long behind so many vehicles you hardly see anything else. That R-11 wasn't made long then, I bet it's harder to find parts for, but tougher so shouldn't need them. Electric units are probably the same for both, that output shaft/drum gear and the planetary set are the wear parts I'm thinking might be hard to find.

 

Heres teh T-85

 

Looks the same as the R-10 OD. AMC used the T-85 behind sixes and their small V-8 (287, OD was gone in 70 when the 304 came out), but with the R-10. Even the 327 used the R-10, or so I thought! It might actually have an R-11 OD, I've only had six cylinder models.