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| | | | Joined: Dec 2010 Posts: 62 Wrench Fetcher | | Wrench Fetcher Joined: Dec 2010 Posts: 62 | Torque tube 1948 half ton.
Looking to replace three speed with a four speed. From a 1949 half ton is that going to be an easy fit without any adjustments?
Thanks | | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 |
You'll need a 1/2 ton 4-speed u-joint assembly. A 4-speed yoke on the transmission side and a 1/2 ton 3-speed yoke on the drive-shaft side.
The 4-speed transmission will need to have the enclosed drive-shaft rear cover/housing.
Do you have the transmission rear-support/mount and the frame cross member (it was sometimes removed, but should be used with a 4-speed).
| | | | | Joined: Oct 2006 Posts: 9,671 'Bolter | | 'Bolter Joined: Oct 2006 Posts: 9,671 | If you are talking about an SM420 4speed you gain nothing by
replacing the 3speed with it. The 1st. gear is almost unsuable
it's so low, which means you'll be driving it in 2nd, 3rd and
4th all the time. I'm sure you are aware that high gear in both
is 1:1.
The four speed will add 70 pounds to the truck and the stick
will be in the crotch of anyone sitting in the middle.
If your 3speed is broke, they're a simple transmision to repair
and with a little searching 'round parts are fairly easy to find.
Denny Graham
Sandwich, IL
Denny G
Sandwich, IL
| | | | | Joined: Jan 2002 Posts: 2,254 'Bolter | | 'Bolter Joined: Jan 2002 Posts: 2,254 | I did the switch. Simply to get a floor shift. That is all you get. And a granny gear to walk up walls.
I am happy. I have a floor shift
Dennis
-there is nothing stronger than the heart of a volunteer-
| | | | | Joined: Dec 2010 Posts: 62 Wrench Fetcher | | Wrench Fetcher Joined: Dec 2010 Posts: 62 | I have the U joints the yoke and the cross over member.Will 3 speed ball collar housing work.I just put 3.55 ring and pinion in .I do not carry any wight but I do not want to slip the clutch.From a dead stop, climbing a grade or pulling in to a tight space will the 4speed lower gears help?I must check and see what trans it is,SM420 Burge and Wearner. | | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 | The 3-speed ball collar will work.
The 1st gear has been useful for me when I have 8 people in my 3.55 rear-end Suburban.
Also, the first gear is quite useful when you are in a parade, and for when you are competing in a slowest-truck race (be sure to decrease the idle speed, before entering such a race).
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