4spd convertion?

74fj40

 
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just wondering what exactly is needed for a 4spd conversion? i'd like to do this so i can have 35's maybe 36's and not have a problem. (cause i have the 3spd right now) and also if anyone here has all that stuff for me, that also would be great
 

cruiserjunktion

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hey max

I just did the conversion on my 71. I got all my parts from a 12/74 fj40. The

12/74 has the 4 speed and 3 speed "transition" transfer. (lower gears) I

swapped over the d-shafts, bell housing, & flywheel. My 71 d-shafts are

smaller you may not need to swap those. Since I swapped d-shafts, I had to

swap the flanges on the 3rd members.While doing the conversion I replaced the

following with new components:

Clutch and pressure plate (asain jto best price)
Clutch Master
Clutch Slave
Clutch slave rod
rear main seal
pilot bearing
throw out bearing
clutch fork
fork boot
forkpins
clutch release spring
flywheel bolts
clutch bolts
clutch ball

I get my parts from the local toyoya dealer. Most are in stock or shipped in

overnite no charge.I introduced myself to the dealer GM. He was stoked when

I told him about my project. He once owned a freeborne red fj40. I now get

jobber (cost) prcing at the parts counter.Installation is pretty straight forward.

I had a few hurdles including one MAJOR mistake. After using several bearing

pullers w/o sucess, I made a tool to remove the pilot bearing. It was ez to

make and got the job done in minutes. I will send it to you if you like. I also

rebuilt the parking brake and had the flywheel and brake drum turned. Let

me know if you need any help.

MY MAJOR MISTAKE:

I didnt support the engine when removing the bellhousing from the donor fj40.

The front motor mounts snapped and the motor fell to the groung almost

crushing me. Make sure you support the rear of the motor when removing the

bellhousing.
resto 001.jpg
fj40 tlc 146.jpg
mini.JPG
 
Last edited:

cruiserjunktion

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Max,


I also swapped the clutch slave to the passenger side using the 4 speed bell housing mounts. It will be cooler over there away from the xhaust. To hook the slave to the master, I fabbed a new hardline with a cheapo line bender and some JAP brake line from advance auto parts. ez
 

cruiseroutfit

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I stock the gear, bearing and seal needed... let me know if you need one :D
 

cruiserjunktion

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Max,

I also got a gasket kit for the tranny and xfer. There are a few seals that should also be replaced between the tranny and transfer that are not included in the kits.
 
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Hey not to steal his thread, but I am gonna be doing the same. Except I am gonna put in a 4spd tranny and 4spd transfer case on an f engine. Do I need to change anything besides the rear main seal? Will the 4spd bolt up to the f engine with no problem? Thanks, Chuck
 

Poser

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Flywheel housing Chuck...you will need a four speed version.


:beer:
 
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Kansastitty
Poser said:
Flywheel housing Chuck...you will need a four speed version.


:beer:

And a 4 speed flywheel, if you want to use the 4 speed(diaphragm) type clutch.
I believe you can use the 3 speed flywheel and clutch(three finger) assembly in the 4 speed bellhousing, but the 4 speed is a better design.


Ed
 

Pin_Head

 
 
 
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74fj40 said:
is it a bad idea to ave 35's and a three speeed tranny?
It depends on your intended purpose. You might get tired of driving it every day in stop and go commuter traffic. Personally, I don't think that the slightly lower first gear with the OEM 4sp is worth the trouble, especially if your primary purpose is wheeling it. You will want lower gears off road with 35s. This is one of the situations where you should put some thought into your intended uses so that you don't end up doing the trany swap twice.
 
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74fj40 said:
thanks for the feedback

I think what PinHead is suggesting is that if you want to run 35's and you know you want to offroad it, going to a SM420 or SM465 is the ticket. Much lower first gear(but not synchro) than the Toyo H42.
As Poser has said many times lower gears are expensive, so think this through.
You can go to lower ring and pinion=$$$$+lot of technical work
Lower geared TC=$$$$$
OR a transmission with a lower first gear=$$ and you can do the work.
It is a good mod to do to get the gearing you want and still have some road manners. I think you keep your 3 speed bellhousing and pressure plate, but use a GM disc. There are several writeups in tech.

GL

Ed
 

Pin_Head

 
 
 
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H41 or H41 and Orion wouldn't be a bad way to go either. Pretty good street manners and off road gears too. If you are serious about rock crawling, 35s will be too small too.
 

cruiser_guy

 
 
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74fj40 said:
are the sm420 and 460s, transmissions or transfercases? and the h41 is the transmission i have roight now correct?
The SM420 and SM460 are GM trannys and if your truck is originally from the states and unmolested it will have the H42 NOT the H41 (4 speeds not 3 speeds). The 3 speed is a J30 I think.
 
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cruiser_guy said:
The SM420 and SM460 are GM trannys and if your truck is originally from the states and unmolested it will have the H42 NOT the H41 (4 speeds not 3 speeds). The 3 speed is a J30 I think.


Yeah, CruiserGuy is right. If you have a ;74 it should be a 4 speed, H42. So what makes you think you have a treespeed?
Max, what are you wanting to do with the truck? Are you going to drive it to school? Some wheeling, but mainly a DD?
Lot of guys running 35's and a stock 4 speed.
And are you really HELPING your DAD on this! You better be!


Ed
 
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Poser said:
Flywheel housing Chuck...you will need a four speed version.


:beer:

Hey Kurt (cruiseroutfit) do you have one of these and also the flywheel like degnol was saying? If so let me know a price.

Thanks, Chuck

yeah mel I got some leakin back there, so I believe it's gotta get done.
 
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