I drive with overdrive locked out around town for several reasons: First of all I'm from the generation that thinks part of the fun of a Y block is listening to the pipes when you let off the gas. I just don't like for an engine to fall to an idle when I let off the gas. I don't want it to shift into overdrive on Main street at 35 MPH when I let off the gas. I want to have the 3.89 rears right there if I want to change lanes without having to kick it down first. Or maybe I need to change my driving habits before I get a ticket for aggressive driving.

Kenneth

Fredricksburg, Texas

A famous Indy/road racer (I forget who), when asked many years ago why he didn't use compression braking to slow for corners, replied; "Brakes are a lot cheaper than engines".

6 VOLTS/POS. GRD. NW INDIANA

Philo is right. The freewheeling is at such low speeds that it would not bother brake wear at all.



Tom from the chiggerfarm located in the beautiful Heart of Central Texas

When you cannot dazzle others with your brilliance, baffle them with bullcorn!

Freewheeling is no worse on the brakes than an electric powered vehicle that is not using the generator function for drag when slowing down.  But brakes are cheaper to rebuild than transmissions for what that’s worth.  I've two overdrive cars and simply leave them in overdrive at all times as the free-wheeling part of the operation at low speed is not an issue for myself.

As per the owners manual, just park the car with the gear selector in reverse while using the parking brake to prevent the roll-a-way from taking place.

That’s right.  If the overdrive solenoid is not disengaged and you do manage to get the transmission into reverse, then the planetary gears can be damaged due to the angle of the gear cut not wanting to run in reverse.  The T85 does have an internal linkage built into it to block out the reverse function if the solenoid is engaged but nothing says that particular linkage can get bent or out of adjustment thus allowing the transmission to go into reverse and subsequently destroy the planetary gears.

Lorena, Texas (South of Waco)

I think that freewheel would be harder on brakes, but probably not as much as aggressive driving habits, and in order to prevent runaway, it has to be parked with the transmission in reverse gear. It has a lockout feature that should prevent shifting into reverse with the overdrive engaged.



Tom from the chiggerfarm located in the beautiful Heart of Central Texas

When you cannot dazzle others with your brilliance, baffle them with bullcorn!

In normal unmodified operation in O.D., The trans only freewheels below about 28 mph. Therefore no real extra wear on the brakes. When parking, either lock out the O.D. with the dash cable or shift into reverse which locks it out inside the transmission. There is no harm in backing up with the overdrive engaged.

FIGHT CONFORMITY! 

I know very little about O.D.s but a couple of things come to mind. How much of this applies to a modified unit, I'm not sure. Free wheeling in the city is hard on brakes is it not? And as I understand it, if parked in free wheeling, without the emergency/park brake on, can result in a run away. Also, I believe I read here or elsewhere that it's possible to damage the O.D. if not disengaged, while backing up. Is that correct?

Paul

Welcome to the site.  Looks like we are neighbors as I’m just a hop and a skip outside of Waco.

Lorena, Texas (South of Waco)

About freewheeling; I also own a '68 SAAB 95 (the '95' denotes a station wagon back then...and by the way, thanks gm for destroying the marque...real nice!)

It has the FORD 91 cu. in. V4 (a GREAT engine design). It has a column shifted 4 spd with a freewheeling feature which can be locked out. I believe this feature was useful on the two-strokes to eliminate the annoying popping on deceleration. I leave it locked out. I like engine compression braking when I lift my foot off the throttle and as "Chigger" says, those one-way roller clutches aren't designed to take a whole lot of abuse. 

With the gearing in my Ranchero, 3.01/1 in O.D., any speed over 30 mph on level streets is fine without lugging the engine. And I just don't want to fiddle around with a switch! 

FIGHT CONFORMITY! 

Hello everyone, I'm a new member and do not see a place to introduce myself. Since I wanted to reply to this thread I thought this would be as good a place as any. I am from the Waco, Texas area.

On the topic of freewheeling, I agree that it is wonderful for in town driving, I just wanted to say to go easy on the one-way clutch, because it doesn't like froghopping. They are easy to tear up if you get a little aggressive with the driving. I don't usually lock out for town, but am careful, as I know all of you are.



Tom from the chiggerfarm located in the beautiful Heart of Central Texas

When you cannot dazzle others with your brilliance, baffle them with bullcorn!