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| | | | Joined: Mar 2010 Posts: 32 New Guy | | New Guy Joined: Mar 2010 Posts: 32 | Is it possible to replace the fourth gear in a standard four speed, and move 2, 3 and 4 to 1,2,3. This might allow me to build a highway truck without having to do away with the torque tube and original rear end? The four speed needs to be rebuilt anyway. | | | | | Joined: Feb 2002 Posts: 12,029 Cruising in the Passing Lane | | Cruising in the Passing Lane Joined: Feb 2002 Posts: 12,029 | there's nothing you can do to a 'standard' 4 speed that will change the fact that the highest gear is 1:1, you cannot convert it to an overdrive .... depending on the year, you may be able to just replace the rear gears, keeping the closed drive
Bill | | | | | Joined: Aug 2004 Posts: 1,418 ODSS Lawman | | ODSS Lawman Joined: Aug 2004 Posts: 1,418 | There are some options you can do to improve highway speeds and keep a closed driveline. First, based on what year of truck you have, you can install a 3:55 gearset and will improve road manners greatly. Also, you can find and install a Trukstell overdrive unit. This unit installs behind the transmission and is for closed drivelines.
SWEET Sergeant At Arms: Old Dominion Stovebolt Society BUNS?!?!?!Where we're going, we don't need no buns.....1950 GMC 450 1951 Chevy 1/2-TonThe GreenMachineIn the Stovebolt Gallery | | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 | danorris, What year/model truck? Do you have the original rear end? Additional information: Patrick's or Mothertrucker's 3.55 Ring & Pinion gears in a 1/2 ton enclosed drive-shaft (torque tube) rear end (if 1937-54) The Truckstell (Tip-Toe-Matic) overdrive unit (0.73 ratio) requires cutting the torque-tube and enclosed drive-shaft. | | | | | Joined: May 2005 Posts: 487 'Bolter | | 'Bolter Joined: May 2005 Posts: 487 | If, by "standard" 4-speed, you mean the SM-420, I don't know of any way out.
For a Muncie M-20, there is a kit to change it to have an overdrive top gear. This is an attractive option for the muscle car guys, because it looks bone stock from the outside, and requires no mods to the car at all.
regards,
Leon | | | | | Joined: Oct 2006 Posts: 9,671 'Bolter | | 'Bolter Joined: Oct 2006 Posts: 9,671 | Hey Leon, where is that kit avalable??
DG
Last edited by Denny Graham; 02/22/2013 3:37 PM.
Denny G
Sandwich, IL
| | | | | Joined: Mar 2010 Posts: 32 New Guy | | New Guy Joined: Mar 2010 Posts: 32 | I am aware of patrick's..I'll look up Mothertrucker's. A guy here who worked for GM and then a local transmission shop says there is a Richmond kit that will do it, but your feedback will help me stay out of trouble on this one. The truck is a 51 3100. The 4 speed is an original out of a 48 truck. As far as I know, the rear end is original to the truck.
Dave | | | | | Joined: Mar 2010 Posts: 32 New Guy | | New Guy Joined: Mar 2010 Posts: 32 | Thanks, Tim. I'll post again when I get the final story on this.
Dave | | |
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