The Ford Barn

olfarmer · 04-20-2011, 06:58 AM

On making my 40 pickup a better driver it was suggested changing out the four speed for a three speed transmission and changing the rear end gear ratio. In looking the parts I was wondering if it would be better to look for the 42 and up open drive line rear end and a three speed trans that would work. Is there any advantage to the open rear end verses the closed drive line. Any problems making the swap?
Thanks in advance
Mike

Charlie ny · 04-20-2011, 07:34 AM

Mike,
With the closed drive comes the torque tube which is THE major
element in keeping the rear axle in place. It's certainly not an over-
whelming job to go to an open drive but either you switch to parallel
rear springs or keep your present rear spring and split the wishbones
then add an additional upper control arm blah blah blah.
In my personal experience I have a '41 pickup with an 8ba
and closed drive and it's golden.
I received your message on the private section of the Barn, I'm
not sure my reply went thru.....call or email when you have chance,
if you wish. 716 662 [email protected]
Charlie ny

rotorwrench · 04-20-2011, 09:52 AM

The "78" case three speed center shift transmission can be found in the 39 passenger cars but they were used in pick ups from 1939 to 1950 so are still common. The work it takes to convert to open drive would be excessive in my book. The open drive transmission can be easily converted to the passenger car configuration by changing the rear mount to whatever one will work for you. The guts from any side load remote control car transmission from 1940 to 1948 can be used to fill the case.

Mac VanPelt has an excellent book on identification of gears and overhaul of these venerable old cog boxes. Check his web site for info.

Kerby

Mart · 04-20-2011, 10:53 AM

Open drive would be a load of work for no real advantage.

Just find a good 3 speed box, bolt it in and run your present axle.

Mart.

41PICUP · 04-20-2011, 12:56 PM

Check out the Mitchell Overdrive, either 26 or 36%.

kiwitony · 04-20-2011, 02:29 PM

Sponsored Links (Register now to hide all advertisements)

I like those plywood wheels to move it around,very neat.

Gumpy · 04-20-2011, 05:08 PM

three speed transmission is good,,,open drives advantage is taking out transmission,,,to repair it or resurface flywheel or replace clutch which is a lot easier than enclosed driveline....I have owned both and prefer the original driveline....just looks alot cooler under the pickup!!

38 coupe · 04-23-2011, 09:26 AM

I second the idea of installing a Mitchell overdrive.

04-20-2011, 06:58 AM	#1
olfarmer Junior Member Join Date: Apr 2011 Location: Davis Oklahoma Posts: 18	open or closed drive line On making my 40 pickup a better driver it was suggested changing out the four speed for a three speed transmission and changing the rear end gear ratio. In looking the parts I was wondering if it would be better to look for the 42 and up open drive line rear end and a three speed trans that would work. Is there any advantage to the open rear end verses the closed drive line. Any problems making the swap? Thanks in advance Mike

04-20-2011, 07:34 AM	#2
Charlie ny BANNED Join Date: May 2010 Posts: 3,019	Re: open or closed drive line Mike, With the closed drive comes the torque tube which is THE major element in keeping the rear axle in place. It's certainly not an over- whelming job to go to an open drive but either you switch to parallel rear springs or keep your present rear spring and split the wishbones then add an additional upper control arm blah blah blah. In my personal experience I have a '41 pickup with an 8ba and closed drive and it's golden. I received your message on the private section of the Barn, I'm not sure my reply went thru.....call or email when you have chance, if you wish. 716 662 [email protected] Charlie ny

04-20-2011, 09:52 AM	#3
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,425	Re: open or closed drive line The "78" case three speed center shift transmission can be found in the 39 passenger cars but they were used in pick ups from 1939 to 1950 so are still common. The work it takes to convert to open drive would be excessive in my book. The open drive transmission can be easily converted to the passenger car configuration by changing the rear mount to whatever one will work for you. The guts from any side load remote control car transmission from 1940 to 1948 can be used to fill the case. Mac VanPelt has an excellent book on identification of gears and overhaul of these venerable old cog boxes. Check his web site for info. Kerby

04-20-2011, 10:53 AM	#4
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,745	Re: open or closed drive line Open drive would be a load of work for no real advantage. Just find a good 3 speed box, bolt it in and run your present axle. Mart.

04-20-2011, 02:29 PM	#6
kiwitony Senior Member Join Date: Aug 2010 Location: Whangaparaoa New Zealand Posts: 263	Re: open or closed drive line Sponsored Links (Register now to hide all advertisements) I like those plywood wheels to move it around,very neat.

04-20-2011, 05:08 PM	#7
Gumpy Senior Member Join Date: May 2010 Location: Sf bay area Posts: 1,464	Re: open or closed drive line three speed transmission is good,,,open drives advantage is taking out transmission,,,to repair it or resurface flywheel or replace clutch which is a lot easier than enclosed driveline....I have owned both and prefer the original driveline....just looks alot cooler under the pickup!!

04-23-2011, 09:26 AM	#8
38 coupe Senior Member Join Date: May 2010 Location: South Texas Posts: 1,631	Re: open or closed drive line I second the idea of installing a Mitchell overdrive.