Here's a Ford 6 speed http://www.ddperformance.com/images/t56stlbell.jpg
http://www.ddperformance.com/images/46viper1.jpg

Here a place that makes adapters http://www.rodshop.com.au/transmissions.htm
http://www.transmissionadapters.com/

Then upgrade the input shaft on transmission to match up with the crank shaft and pilot bearing.

 

Of course we are. It would be so much easier to just put a six speed in. One from a salvage yard can't be much more than 1500. I am actually planning an injected 302 with afr heads and the bbk ssi intake with a six speed for my f150. It is going to be mainly a hauler for my Trans Am, but it will be quick and corner good to. Imagine how cool it would be to pull my TA to a track day, unhook, then run my truck against the g-machines, and exotics to get a feel for the track, then unload the trans am

 

The second transmission will be driven on the drive side. I will have two overdrives in 3rd and 2nd in the second trans.........1st and reverse are not used. I have a 4.1 rear and a 30" tire. Not much choice in gear ratios for my rear. I think it is very practical and makes a lot of sense. A ZF5 is great if you have deep pockets. Gear Vendor only gives 28% and a $3000 hole in your wallet. So for $4000 I can have 10 gears.......not much of a bargain. Besides, I don't need to split the gears, I need a couple more gears.

 

Of course we are...........but this stuff keeps me awake at night.

 

WarWagon, you said, "my idea is to joint the two output shafts."

and you said: "The second transmission will be driven on the drive side."

Think about that for a second. If you are driving the (old) output shaft of the second transmission, then the output shaft becomes the driving member in the second trans. Therefore when you engage other gears in the second trans, what would have been the coast side of the gear teeth now does the driving.

 

more sleep is needed! HAHAHAHAHAHAHAHAHHAHAHA

 

I always need more sleep....HA..............any way, Bdox, think of it his way. Imagine a trans floating in the air with the input shaft in your left hand and the out put shaft in your right hand. Now, twist the input shaft clock wise, while holding the out put shaft stationary. You are loading the drive side of the gears. No rotate yourself and the trans 180 degrees. You will find yoursef applying torque in the same direction to the output shaft, therefore driving the proper face of the gears. The only difference is that the trans will be rotating backwards.

 

Your example doesn't work Warwagon. Take your floating in air trans, apply cw torque to the input, then connect the output to the output of a second trans and look at the input of the second trans. From that point of view the input shaft is turning ccw. So if the second trans is in any gear but direct, the coast side of the teeth are loaded. With the trans turning backward and the output driving the input, it is the same loading effect as a normally installed trans when you decellerate.

 

I agree with warwagon, the second transmission would not be loading the coast side of the gears. The way I figured it out was to think of the input shaft on a single transmission being stopped, and coasting forward causing the output shaft to be turned counter clockwise when looking at it from the rear. If two output shafts were mated, the rotation of the second one would be backwards from normal coast rotation and backwards coast loading meaning the power side of the gears would take the loads like normal. The output is turning the input, but since it is turning it in the direction opposite of normal, the gears are still loaded correctly.

 

I concede the point. Since the transmission is turning backwards, and the output shaft is driving, it does follow that the drive side of the teeth are loaded. You guys are right.
It would be like pushing a car backwards while it is in gear. Same forces as engine driving the car forward.

 

Bdox......now you are trying to confuse me, lol......but I understand what you are saying. That would have been a more easy example, but I need to make everything confusing at times. My original plan was to run two 4 speeds, but I think now I will run it behind an auto. I have a totally rebuilt Cad 500 and TH400 I am going to swap into my work truck. I can leave the 4 speed in 4th for around town stop'n go and then use 3rd for the freeway and on occasion 2nd. Caddys have 500lbs of torque at a relatively low rpm, so it should love the gearing. I may just do this.

 

Good for ya WarWagon. I hope you are a good machinist!

 

If you do this, I want pics/videos

 

ok, will do.

 

The second trans. backwards works well. I've installed a couple. Coupling the output shafts is easy, just use the spider from a front driveshaft. Press it into place between the two output yokes. Connecting the rear trans. to the rear drive shaft requires the center spline from an old clutch plate, machine turn the O.D. enough to provide a smooth surface. Also cut the rear spline shaft off an old front drive shaft. Leave a couple inches of tubing with it, so that the rear trans and the short driveshaft your making is equal in length to the front drive that your removing. Machine a steel donut that will press into the drive shaft tubing and over the smooth surface from above clutch center. Weld the four mating surfaces by making short beads at intervals around the seams until the entire seam is welded. This is so the new driveshaft does not draw a bow. Mount the centerline of the rear trans. on the centerline of the orginal front driveshaft. Support the rear trans. at both the front and the rear of the case by fabricating 2 inch angle iron over to both frame rails. Your second shift lever will come thur the floor about 26 inches behind the front shift lever. You will use 4-4 and 4-3 the most. 4-2 on the freeway if your axle is 5 or 6 to 1. You won't use 4-1 unless you are running at Bonneville. I use R-R only to win bets by going forward in reverse. Press a midship bearing on to the spline if you did not leave the old one on. The midship bearing will mount in the same location as it did with two drive shafts. save a good front driveshaft if anything goes wrong you can just replace the whole rear trans assembly with the orginal drive shaft. diesel_john