1968 fj40 transmission question

[Shark1007]

Need a little guidance. I have a 68 fj40, original with small lift kit. Aftermarket seats, no roll bar.
It has a 3 speed original that was converted to floor shift. Paint/body work done. My question.. mechanic that’s doing brakes has a 4 speed from a 78 FJ. The cruiser is just a toy to me, not a daily driver. Question: Do I improve my situation by installing 4 speed? Drive shaft change etc? How bad a swap are we talking?

Thanks in advance.

 

[Shark1007]

Anybody done the swap?

 

[DesertFJ40]

You will need:

4 speed bellhousing and inspection cover

Either new 4 speed drive shafts or modify your current ones by changing their length.

If you go with 4 speed drive shafts, you will need to buy pinion flange adapters. If you modify your 3 speed ones, you won't have to.

You can make it fit but people recommend to cut to torque tube and push it back a few inches so the transmission and t-case have enough room to work on

4-speed skid plate or modify your current one


You can keep your current 3-speed transfer case. It is "recommended" since this will give you lower gearing.

If you keep the 3 speed transfer case, you need a 74 or 75 transition gear to mate up to the 4 speed.

Keep your 3 speed clutch and flywheel.

You might need to make the hole in your transmission hump a bit larger.

4-speed transmission top cover with shift cane.

That's it from what I can remember.

 

[3_puppies]

the 4 speed will make daily driving easier/smoother
you don't gain top speed
it is your choice, but there are still lots of us running 3 speeds

 

[Dynosoar]

3 speed - 3rd gear 1:1
4 speed - 4th gear 1:1
3 speed non synchro 1st
4 speed fully synchronized

Dyno

 

[brooklyn]

I would say a lot of work for little gain - now if you were swapping a complete engine, transmission, and transfer case from a late model FJ60 — I would say you’re getting some real benefits.