# RWD Transmission Linkage? (engineering help)
**URL:** https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965
**Category:** NYSpeed Automotive
**Created:** [July 2, 2009, 4:15am UTC](https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965 "2009-07-02T04:15:29Z")
**Posts on this page:** 20
**Page:** 2
### Author:  [@travisn](https://forums.speedlife.net/u/travisn)
#### Post date: [July 2, 2009, 5:52am UTC](https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965/21 "2009-07-02T05:52:47Z")
Ok, I understand your picture, but I dont understand how it is better to have it that way then to have something on the otherside supporting the load (supporting the ‘axle’, for better terms) from wanting to bend up or down when moved.
---
### Author:  [@newman](https://forums.speedlife.net/u/newman)
#### Post date: [July 2, 2009, 5:53am UTC](https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965/22 "2009-07-02T05:53:58Z")
The difference there is that the transmission end of the clevis is constrained axially, so it is free to rotate and slide in and out… What you’re trying to do increases the moments substantially.
---
### Author:  [@newman](https://forums.speedlife.net/u/newman)
#### Post date: [July 2, 2009, 5:55am UTC](https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965/23 "2009-07-02T05:55:53Z")
> [@travisn](#):
>
> Ok, I understand your picture, but I dont understand how it is better to have it that way then to have something on the otherside supporting the load (supporting the ‘axle’, for better terms) from wanting to bend up or down when moved.
It’s not better to have it in single shear, but chances are the clevis you’re going to buy has garbage fits and will be so narrow that the bearing loads are going to go through the roof…
---
### Author:  [@travisn](https://forums.speedlife.net/u/travisn)
#### Post date: [July 2, 2009, 6:04am UTC](https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965/24 "2009-07-02T06:04:44Z")
I am thinking about making the clevis, and using the same material for the new shifter as I am for the linkage (1/4" x something) so they are the same thickness…
but the way I see it having something on the other side will only spread the load out. That way the force is spread to where the red rod connects to both sides, not just one side
---
### Author:  [@newman](https://forums.speedlife.net/u/newman)
#### Post date: [July 2, 2009, 6:10am UTC](https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965/25 "2009-07-02T06:10:56Z")
ugh. Like i said, loading it in double shear with a clevis will be better but only if you have MORE BEARING SURFACE and a close fit. This whole thing is going to be sloppy as hell unless your tolerances are w/in .005"
---
### Author:  [@travisn](https://forums.speedlife.net/u/travisn)
#### Post date: [July 2, 2009, 6:19am UTC](https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965/26 "2009-07-02T06:19:44Z")
sorry, I fail sometimes
hows this? maybe with a nylon washer…
god paint sucks balls…
---
### Author:  [@newman](https://forums.speedlife.net/u/newman)
#### Post date: [July 2, 2009, 6:24am UTC](https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965/27 "2009-07-02T06:24:43Z")
Something like that will work, but you’re going to want the horizontal members to have some thickness to them… No nylon washer, press a brass bushing into the horizontal members.
What you have drawn can easily be accomplished with 2 solid rod ends…
---
### Author:  [@travisn](https://forums.speedlife.net/u/travisn)
#### Post date: [July 2, 2009, 6:27am UTC](https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965/28 "2009-07-02T06:27:19Z")
1/4" or 3/16" by 1" sufficient? what size diameter bolt should I use?
Nothing in between the horizontal and vertical pieces? Thats a lot of metal to be rubbing together (aka binding), especially if its going to be tight…
---
### Author:  [@newman](https://forums.speedlife.net/u/newman)
#### Post date: [July 2, 2009, 6:42am UTC](https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965/29 "2009-07-02T06:42:17Z")
> [@travisn](#):
>
> 1/4" or 3/16" by 1" sufficient? what size diameter bolt should I use?
>
> Nothing in between the horizontal and vertical pieces? Thats a lot of metal to be rubbing together (aka binding), especially if its going to be tight…
You can use a regular washer, you don’t want anything with any compliance, use a steel washer. Control the tension on the bolt with a locknut and jamnut.
1/4 is kinda thin. Not a lot of bearing surface, but since you’re using a piece of flat stock, you don’t want a lot of bulk. I still say use solid rod ends… you’re doing some fairly precise work here, 1/32 of “slop” at your bolt with a 1/4" thick plate is going to allow the new shifter to wiggle 2" total.
---
### Author:  [@travisn](https://forums.speedlife.net/u/travisn)
#### Post date: [July 2, 2009, 6:57am UTC](https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965/30 "2009-07-02T06:57:51Z")
So you still are going to back to your original drawing then? I still dont see how a 1/4" piece of metal with a 1"x1" contact patch will be less than a solid rod end like what you drew…
---
### Author:  [@newman](https://forums.speedlife.net/u/newman)
#### Post date: [July 2, 2009, 6:59am UTC](https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965/31 "2009-07-02T06:59:46Z")
Because the force is not transmitted through the FACE of the rod end. It’s transmitted through the bolt into the round hole of the rod.
---
### Author:  [@travisn](https://forums.speedlife.net/u/travisn)
#### Post date: [July 2, 2009, 9:43am UTC](https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965/32 "2009-07-02T09:43:12Z")
What I was talking about is if the bolt ‘bends’ or moves that the thickness/width of the plate will hit the shifter thus allowing the force to be applied that way?
ok, that being said, you would do 2 solid rod ends on each side? I just dont see the difference of solid rod ends vs plate steel with a hole in it.
what kind of thicknesses are you talking about being necessary here? 1/2" for the horizontal members, 1/2" bolts? 1" square solid vertical pieces?
---
### Author:  [@newman](https://forums.speedlife.net/u/newman)
#### Post date: [July 2, 2009, 9:46am UTC](https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965/33 "2009-07-02T09:46:14Z")
5/16 bolts will probably be fine.
---
### Author:  [@travisn](https://forums.speedlife.net/u/travisn)
#### Post date: [July 2, 2009, 9:52am UTC](https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965/34 "2009-07-02T09:52:18Z")
here is a good picture of what I am working with (not a picture of _my_ engine, but you get the idea)
I figure I will have to cut the shifter down to 4" or 5" so it doesnt hit the floor, depending on on the height of the rear of the tranny for drive line angle.
From what I can remember the shifter will need to be somewhere in between the vent and where the two case halves come together, ill be able to get an exact measurement this weekend when I decide where the motor mounts will go
---
### Author:  [@Southtowns27](https://forums.speedlife.net/u/Southtowns27)
#### Post date: [July 2, 2009, 10:00am UTC](https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965/35 "2009-07-02T10:00:02Z")
> [@travisn](#):
>
> What I was talking about is if the bolt ‘bends’ or moves that the thickness/width of the plate will hit the shifter thus allowing the force to be applied that way?
>
> ok, that being said, you would do 2 solid rod ends on each side? I just dont see the difference of solid rod ends vs plate steel with a hole in it.
>
> what kind of thicknesses are you talking about being necessary here? 1/2" for the horizontal members, 1/2" bolts? 1" square solid vertical pieces?
The deflection of the bolt should be negligible in this application. A bolt is not its strongest in a shear situation, but we’re only talking a couple hundred pounds of force in your case. (They hold jet engines on the wings of some planes with two 1/2" bolts btw)
You don’t need rods on each side (a total of 4). If the rod ends are the same thickness as the plate steel you want to use (I don’t understand why you want to go this route) the bearing area will be the same and it should work just the same. Albeit not as aesthetically pleasing. Keep in mind that the rod ends are designed to have a brass/bronze bushing installed in them-they are machined for an interference fit with the bushing. The inside diameter of the bushings are machined to a close tolerance to fit the bolt tightly. If you don’t have close tolerances on the bolts you’ll have a ton of slop in the shifter. If you want to use your flat bar, fine, but you’ll have to drill a hole in it that A) fits the bolt you’re using with about .005" tolerance, B)allows a brass bushing to have an interference fit in the flatbar. Either way, you need to drill a precise hole. You’re not going to accomplish this with a 3/8" hand drill and a box of dull drill bits.
You had mentioned that you don’t want to use threaded rods since they will loosen up. They can’t-since the ends of the rods are bolted rigidly to the shifters they are not allowed to rotate. There will be torsion applied to the rods so the threads will want to rotate on themselves, but a locknut will solve that problem.
---
### Author:  [@newman](https://forums.speedlife.net/u/newman)
#### Post date: [July 2, 2009, 10:02am UTC](https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965/36 "2009-07-02T10:02:49Z")
> [@Southtowns27](#):
>
> The deflection of the bolt should be negligible in this application.
> You don’t need rods on each side (a total of 4). If the rod ends are the same thickness as the plate steel you want to use (I don’t understand why you want to go this route) the bearing area will be the same and it should work just the same. Albeit not as aesthetically pleasing. Keep in mind that the rod ends are designed to have a brass/bronze bushing installed in them-they are machined for an interference fit with the bushing. The inside diameter of the bushings are machined to a close tolerance to fit the bolt tightly. If you don’t have close tolerances on the bolts you’ll have a ton of slop in the shifter. If you want to use your flat bar, fine, but you’ll have to drill a hole in it that A) fits the bolt you’re using with about .005" tolerance, B)allows a brass bushing to have an interference fit in the flatbar. Either way, you need to drill a precise hole. You’re not going to accomplish this with a 3/8" hand drill and a box of dull drill bits.
> You had mentioned that you don’t want to use threaded rods since they will loosen up. They can’t-since the ends of the rods are bolted rigidly to the shifters they are not allowed to rotate.
:hifive:
---
### Author:  [@travisn](https://forums.speedlife.net/u/travisn)
#### Post date: [July 2, 2009, 10:16am UTC](https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965/37 "2009-07-02T10:16:39Z")
well all I have is a 3/8 drill and a box of dull drill bits (well I have good bits in my tap and die set, lol). I have had good success so far with a 1/8 pilot hole and a step drill.
I want to use the plate steel because I am poor.
---
### Author:  [@Southtowns27](https://forums.speedlife.net/u/Southtowns27)
#### Post date: [July 2, 2009, 10:24am UTC](https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965/38 "2009-07-02T10:24:29Z")
> **[McMaster-Carr](http://www.mcmaster.com)**
>
> McMaster-Carr is the complete source for everything in your plant. 98% of the products ordered ship from stock and deliver same or next day.
part #6066k36
$8.55
part #1581k12
$15.17
The female rod ends are not available with an I.D. of 5/16", but they come in 3/8" so you’ll have to use a 3/8" bolt on one end of your linkage.
You need 2 of each of the above parts. Under 50 bucks and you don’t have to fuck around for hours.
---
### Author:  [@newman](https://forums.speedlife.net/u/newman)
#### Post date: [July 2, 2009, 10:27am UTC](https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965/39 "2009-07-02T10:27:34Z")
depending on length, you may need to get 4 females and some threaded rod.
---
### Author:  [@Southtowns27](https://forums.speedlife.net/u/Southtowns27)
#### Post date: [July 2, 2009, 10:59am UTC](https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965/40 "2009-07-02T10:59:50Z")
…or male ends, one right hand thread, one left hand thread, and have a sleeve machined accordingly. Adjustable ftw
but that would add expense and be needlessly complicated
[Previous page](https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965.md?page=1)
[Next page](https://forums.speedlife.net/t/rwd-transmission-linkage-engineering-help/69965.md?page=3)