SM420 questions

[yotawheeler]

ok so i have most of my stuff together but i just had a few questions:

will i have to use a 3spd pressure plate or can i use my orig 4spd one if its in good shape

can my clutch slave stay in the same place (pass side) or do i have to move it

how much do i have to change my drive shafts? shorten, lengthen? how do i determin the needed drive shaft length

iv searched on this and also read the tech section and i just want to make sure everything is clear in my head before i pull the tranny. this is going into a '74 FJ40 with a 2F and 4 spd trans. i have the SM420 mated up to the 3spd case and all the major parts taken care of i think.

thanks

 

[Cruiserdrew]

ok so i have most of my stuff together but i just had a few questions:

will i have to use a 3spd pressure plate or can i use my orig 4spd one if its in good shape

can my clutch slave stay in the same place (pass side) or do i have to move it

how much do i have to change my drive shafts? shorten, lengthen? how do i determin the needed drive shaft length

iv searched on this and also read the tech section and i just want to make sure everything is clear in my head before i pull the tranny. this is going into a '74 FJ40 with a 2F and 4 spd trans. i have the SM420 mated up to the 3spd case and all the major parts taken care of i think.

thanks

You can use the 4 speed clutch with the chevy 11 inch friction disc

Slave can stay on the right side

On the driveshafts, you have to bolt it up and measure. Remember on the front, you need to run a 3 speed yoke and turn it down a bit to clear the side of the SM420 reverse bump. You can use your 4 speed e-brake drum.

The safest way to get the length right is to install everything, and then neasure flange to flange. Have a driveline place size them based on that measurment. The rear can probably be used as is, but it will be extended 3/4 of an inch more than it is now. The front should be shortened because you don't want it to bottom out and break your t-case.

It's a very good swap. What plate are you using?

 

[kyot4x4]

You have to use the 3 speed bellhousing to mate the sm420 to the toyota engine. the 4 speed bellhousing has the wrong bolt pattern. Im not sure what else is needed on the 2f conversion but I had to use a chevy disk, pilot bearing adapter,new trans input bearing retainer and a hand full of little parts.You should do a search there is a lot of info on mud and the net on this subject. I hope it works for you I love mine . use it as a daily driver and no problems yet. good luck
Kyle

 

[Pin_Head]

The 420 with a plate adaptor is 3/4 inch shorter than the 4sp, so you would need to shorten the front and lenghten the rear. If you don't have a lot of lift, the stock rear shaft may be OK. For the front, you can drill new holes in the spring pads to locate the axle 3/4 inch forward to avoid shortening the shaft.

 

[yotawheeler]

awesome! thanks guys. i have no lift but will be running 35" tires so i will probably modify my d-shafts. its going to be mailny a bush rig and only legal enough to get to and from trails without any trouble from the cops....so what i was thinking is cutting and welding a sleeve over top of the original to get the correct length.

thanks! looks like i have something to do today