2f and 4 speed into a 71-any pointers?

[bsmith123]

I have a deal on a 2f with 88k miles I plan to just inspct for leaks, clean and install it--any pointers?

I posted some questions about the 4spd to 3spd xfer case but I may also get the 4 spd case as well so I am undecided as of yet if it is worth it to keep the 3 speed xfer

Anyone have any advice or pitfalls to watch for?

I think I'll order new mounts while I am at it

 

[Trollhole]

New mounts would be a good idea.

I'm pretty sure you will need a 4spd tranny tunnel.

If I had it sittting on the ground I'd replace the rear main oil seal and clutch as well as the seal between the tranny and transfer case as well as the drum brake seal.

I'd also check for play on the rear output shaft.
Exhaust gasket.

 

[shelfboy1]

i have 4 speeds in my 65 ,69 and 70 and they all bolted in using stock toyota parts.you just need the correct parts.check the search function and you will find all the info you need good luck

 

[D'Animal]

What vintage 2F.

If it is from a later FJ40 or FJ60 you may want to take some smog stuff off before you install.

I agree with Trollhole. While it is out, pull the pan and replace the seal and the pan gasket. Check a few of the bearing while you are in there.

 

[7mag]

Change the cam plug!!!!

 

[scott johnson]

4 spd tranny 3 spd case is the way to go. Did mine just before GSMTR thanks to some parts help from Trollhole. The result was incredible crawl ratio. Actually used 2nd and 3rd gear climbing some trails.Especially with 4:88 gears and the dual friction clutch. It will spin all 4 tires on the rocks with the stock 72 f motor. No need for a V8 here.

 

[scott johnson]

Did the parts Trollhole suggested plus added the overflow kit so oil can drain back to the transfer case from the tranny if the seal goes. Did the sleeve on the parking brake to address the infamous parking brake leak.

 

[Cruiserdrew]

4 spd tranny 3 spd case is the way to go. Did mine just before GSMTR thanks to some parts help from Trollhole. The result was incredible crawl ratio. Actually used 2nd and 3rd gear climbing some trails.Especially with 4:88 gears and the dual friction clutch. It will spin all 4 tires on the rocks with the stock 72 f motor. No need for a V8 here.

I do not agree. The 3 speed transfer has 2.23 low range, and the 4 speed has 1.99 low range. That isn't enough different to be worth it unless you already have the stuff for the swap. I know some have swapped 3 speed gears into 4 speed cases, but I'm not sure I'd even do that. If you are considering that, a better swap is an FJ60 4 speed and t=case, since that t-case is a major strength upgrade and 2.29 low range. But then you have to deal with the e-brake issue.

The only pointer I could give is to install the motor/tranny/t-case all as one unit, since it will barely fit with the crossmember if you try to build in place. And I agree that replacing all the engine seals makes sense while it's out of the truck and access is easy.

 

[bsmith123]

crawl

yeah the 4.99 gears probably account for the nice torque more so than the 3 speed xfer case. I'm not as concerned with that I think as I am with keeping the PTO winch

I think from what I read you can add a gear to the 4 speed and add length to the pto shaft and keep it but would it be easier to do the 4 speed to 3 speed transfer mod and keep the PTO that way?

 

[Pin_Head]

The 3 speed transfer has 2.23 low range, and the 4 speed has 1.99 low range. That isn't enough different to be worth it unless you already have the stuff for the swap. .

X2

It isn't worth the money and effort.

 

[orvis17]

I did this swap as well and went with a 2f engine, 4 spd tranny, and 3spd transfer.
Some issues I had were:
1-transfer case shift linkage...make sure you steal the cone from your 4 spd transfer case
2-drive shafts will not be the correct length
3-clutch slave cylinder mounts on opposite side passenger side vs. driver side. Had to build and bend new tubing to reach passenger side.
4-call Mark at Marks Offroad. He has everything you need to mount the 3 spd transfer to the 4 spd tranny.

Clutch parts and seals as mentioned previously are a must as long as you are this far in. I did mine and now no leaks.
Also take a look at the oil pan gasket. Much easier to replace now than on your back.

My .02

Dean

 

[Coolerman]

I have seen this debated so many times I wanted to see what the actual figures are for the different combinations. Here is what I came up with... Please check my math in case I'm having a brain fart...

All parameters pulled from FSM of Mud FAQ

Stock parameters
3-speed tranny 1st gear = 2.755, t-case = 2.313, diff = 4.11, Crawl Ratio: 26:17

4-speed tranny 1st gear = 3.555, t-case = 1.99, diff = 4.11 , Crawl Ratio: 29.2:1

4-sp tranny with 3 sp t-case
4-speed tranny 1st gear = 3.555, t-case = 2.313, diff = 4.11 , Crawl Ratio = 33.79:1
Using 750 RPM for the engine, no clutch slipping... flat ground...

We can calculate the actual ground speed in inches per second for all cases. We will use 33" tires which have a circumference of 103.67 for the calculations.

Tire RPM = Engine RPM(750)/Crawl Ratio

So Tire RPM x tire circumference/60 = Ground speed per second


Forward ground speed per second in inches:

3-speed tranny, 3-speed t-case, 4.11 diffs 33" tires: 49.44
4-speed tranny, 4-speed ticase, 4.11 diffs, 33" tires: 44.57
4-speed tranny, 3-speed t-case, 4.11 diffs, 33" tires: 38.35

So there is a 16.21% reduction in forward ground speed [ ((44.57/38.35) * 100)-100 ] using the 3-speed t-case vs. the 4-speed t-case with the 4-speed tranny. I'll take that 16.21% difference!

For those going from the 3-speed tranny to the 4 -speed tranny with 3-speed t-case you will see a 28.91% reduction in forward ground speed!


I have a spreadsheet set up to calculate this stuff with tire sizes from 29" to 40 inch if someone is interested. You can enter the engine RPM, diff ratio, tranny 1st gear ratio and t-case ratio. It also has the ratios listed for many other transmissions and t-cases.
I would like verification of the math? I'm not that great at this stuff...

Link to spreadsheet: www.globalsoftware-inc.com/coolerman/fj40/gearcalc.xls

 

[antFJ]

coolerman.. you need to come do my hw...

x2 on installing as one unit.. that crossmember is RIGHT there... in order to ever get the parking brake drum off your going to have to drop the transfercase.. so you might as well get that squared away too

*edit and probably install the parking brake cable too...

 

[bsmith123]

crawl

Thanks Guys that puts it in better perspective

hmm lets see if I can do the math too?

Laziness ^2 x time to complete + rush factor/crawl + cool factor = time to decide if I want to have parts on hand in time I think!

if I have it right you would go 30 feet further in one minute with the 4/4 set up than you would with the 4/3 based on the approx 6 inch per second difference put that way it seems a pretty significant difference

I have read the 4 speed case is stronger and some put the 3 speed gears in the 4 speed case and go that route with the 4 speed trans

I am getting to the point where I really want to get it on the road but why do the work twice? I have a little time to dwell on it now before my engine arrives

 

[MDH33]

I'm basically doing the same conversion you are except I already have my 2F in. I'm going to go the easy route and use the 4 speed case. Then, when I have some extra money down the road, I'll drop in the Orion to gain some crawl. In the meantime, I'll just rely on good old fashioned momentum to get me up and over those obstacles (and my newly installed PTO might help too).