Overdrive tranny

[theskytoucher]

I was wondering if there is an overdrive manuel transmission that is a bolt in replacement for a t-18.

[willowbilly3]

The T85 should be pretty close. I am not sure if you can keep the same bell housing or not and the driveshaft length might be a bit different.

[theskytoucher]

Is the t85 a 4 speed or a 5 speed

[willowbilly3]

It's actually a 3 speed but has overdrive in every gear. As originally installed a lockout device keeps it from working in first so it would be a 5 speed. With manual contol it would be 6.

[theskytoucher]

I've never heard of anything like that. Is it a Column shift or floor. And if its a colum can it be converted to a floor.

[steveheer]

They are column shift but just like any other 3 speed they could be converted to the floor. The overdrive works off a sprag clutch off the back of the 3 speed so there is a lockout lever. When the lockout is pulled it works like any other 3 speed. When it is released it will coast forward until the transmission output reaches driveline speed. In other words from a dead stop it starts normally then if you let off the gas, the engine will idle while the truck is still at speed. Anyway that's the overrunning clutch that the overdrive requires to "overdrive". So if you take it to say 50 mph, activate the selenoid, then let off the gas (or clutch it) you are in OD.

I have one in my 69 and it's cool. The only drawbacks are no syncronized first gear (which the original toploader had) and hard to find parts.

Oh, one other thing. They are not a good trans for pulling boats out of the water! They have around a 3 to 1 first gear--ok for normal stuff or light towing--

IMO

[theskytoucher]

Well im not planning on doing any pulling im building a street truck so that might be the way to go. Thanks