[Oletrucks] Fwd: 3 speed overdrive conversion

[Emory Hodges]

Hi,

I just did this transmission conversion along with an engine change:

Truck - all original 48 Chevy 3/4 ton with original (and TIRED) 216.
216 ran poorly; leaked (saturated the clutch), etc. Decided against rebuild of
a babbit pounder.

Found a 54 (powerglide) 235 full pressure engine that "had been already
rebuilt."  It has a 56 head and hydraulic lifters.
While getting the engine ready to install, found a 3 speed w/ OD transmission.

Make sure you get a good schematic and understand the electronic side of the
OD. It's pretty simple but you can further simplify with a dash mounted switch
control instead of the speed switch and kick-down switch set-up.

I can try to find some of my document links if you need.

Transmission bolts right up. Study your shift linkage carefully, I had to use
a hybrid of the links and shafts - not hard but just be a little creative. You
will need a new drive shaft with probably an EARLY powerglide yoke. Local shop
made mine complete with yoke and u-joints for just under $300.

Since I was going away from fully original with the 235 I made a few other
changes:
1) 12V conversion with a Optima battery. (OD was a 12V unit anyway) (kept foot
starter for "cool factor.")
2) Electronic cooling fan - great change - safer in so many ways
3) Alternator instead of generator. Left the voltage regulator on the firewall
just for looks.

Good news - transmission is really cool! It sometimes requires a clutch action
to up-shift but downshift works great - it momentary cuts ignition to allow
shift.

Bad news - engine knocks under load. After I got the valves quiet and not
sticking; convinced myself the knock must be bottom end since it is only under
load and around 1500-2000 rpm.   Looks like I'm in for a bearing change.

Let me know if you need help with the OD. I can send pictures or links to
info.

Merry Christmas to all!

Emory Hodges


Today's Topics:
   1. 3 speed overdrive conversion (Kinderlehrer)
  2. Re: 3 speed overdrive conversion (William Schickling)

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Message: 1
ate: Sun, 11 Dec 2011 10:24:22 -0800
rom: "Kinderlehrer" <kinderlehrer at comcast.net>
o: "Oletrucks \(oletrucks\)" <oletrucks at autox.team.net>
ubject: [Oletrucks] 3 speed overdrive conversion
essage-ID: <000001ccb832$1b58ecf0$520ac6d0$@net>
ontent-Type: text/plain; charset="us-ascii"
Happy Holidays everyone.  I just acquired a 3 speed od trans that came out
f a 57 Chevy sedan  engine unknown. I am thinking of installing it in my
6 = ton which at some point was converted from 3 speed column to 4 speed
loor. I have a 235 6 cyl engine.

Has anyone done this? I havent measured, but Im guessing that I will have
o get the drive shaft modified, does anyone know for sure? I would like to
onvert back to 3 on the tree with the od, but I dont have any of the
inkage or shift components and there appear to be a lot of them and they
rent cheap.
Thanks,
Bob

-----------------------------
Message: 2
ate: Sun, 11 Dec 2011 13:37:58 -0500
rom: "William Schickling" <wschick1 at twcny.rr.com>
o: <kinderlehrer at comcast.net>
c: Oletrucks at autox.team.net
ubject: Re: [Oletrucks] 3 speed overdrive conversion
essage-ID: <000001ccb834$01a82a30$04f87e90$@twcny.rr.com>
ontent-Type: text/plain; charset="us-ascii"
Bob,
I wish I had more info for you. I had a 52 3/4 ton with this conversion. I
oved it. It had a toggle switch on the dash for the overdrive. It
reewheeled half of the time. I don't remember which (overdrive in or out).
Since mine was an open drive conversion from closed drive it definitely had
 new drive shaft and rear-end. Mine was on the column and it was a blast to
rive. I can compare it to my 1940 3/4 ton. Top Speed on the 40 is about 40,
aybe 45. The 52 could do 55 to 60.  I should never have sold that truck :)
The column shift used arms on the steering column. Is that still there or do
ou need a new column?
Bill (Haven't replied to a list serve email in too many years) Schickling