Swapping Input Shafts for FJ Case for Manual Transmission

LOL, well at least it was partially drained. You sir are a true optimist.

 

I opened the drain plug and barely any came out lol

I'd say I dumped about 1.3 quarts on my floor and the trans only holds 2 quarts.

 

Holy shit haha, hopefully nothing in the trans is burned up. When I re-installed my crawler box I sealed the trans mount holes with RTV because that area is "supposed to be" filled with gear oil according to Marlin. Did you have any oil coming out of there or did it stay sealed within the cavity pretty well?

 

I had a few drips but that area was sealed surprisingly well. As I was about to separate the t case I was like "maybe I should put my sheet pan down to catch any oil drips". Then wooooosh, fucking oil everyyyyyywhere hahaha

 

Thanks for keeping this writeup alive and adding to it Randy. Came in handy for me today

 

Awesome! Happy to hear. It was instrumental for me as well when I did the swap.

 

I spent the better part of last week re-reading (the Let's see your FJ case swap) 125 page long novel, noting, re-thinking the front ADD (now going to pull it too, move it over the collar and place a hose clamp to keep it in place, and then plate the opening off) and today began my swap:
My plan is to get the FJ Case opened up today and then next Friday after work park the Taco and start to pull my case, and the plan will be to have it drivable back to work the following Monday.

So on the FJ case; I pulled the front (4x) flange, unstaked and removed the 30mm nut, removed the 12 (12mm case bolts) and with a big crow bar got the case to pop, and it wiggled out about 3/4 of an inch but won't or isn't being cooperative coming all the way apart.
Did I need to (not sure how) pull the coupling off of the front of the input shaft? I didn't read anywhere about that... and it seems to be slightly smaller diameter than the seal it seems like it is going to pull through...?
Did I miss a step? Reading the FSM - VF2A TRANSFER – TRANSFER ASSEMBLY TF REMOVAL 1. DICONNECT it seems to indicate in step 4 & 5 remove the Retainer sub assembly and cover oil seal..

 

There’s no need to remove that flange to separate the case. All you’ve gotta do is remove the front driveshaft output as well as the shifter and the 12 bolts but it sounds like you already did all of that.

You can see in this pic how it looks separated, that front input shaft stays in place so no need to remove that seal/flange thing.

I guess just keep wiggling and prying until it comes apart?

as far as the ADD all I did was put my truck into 4hi and disconnect the 4wd ecu. It leaves the add actuated all the time and really no risk of it undoing itself. Very easy and free.

 

the front coupler doesn’t need to be removed if you’re doing a straight swap to an auto but if it’s going behind a crawl box I believe needs to come out. Don’t know exactly what the rear output of the auto looks like whether it’s male or female. If your putting this case behind the 6 speed transmission you’ll need to swap input shafts with a 22 spline input from your existing case. Removal of the coupler is not required to swap the whole input shaft over.

 

And perhaps I didn’t answer your question if it does need to be removed there are two ways I’ve seen performed

1- bearing splitter and a press, the benefit here is the coupler is not damaged if you ever need it again but requires the press and splitter if you don’t have one and takes more time


2- weld a giant nut to the end of the coupler and thread a bolt on there to press it off. Probably won’t be able to reuse the coupler at this point but it’s a lot faster method to remove it.

 

I think his question is just “how do I get this case apart?” Because it’s not coming apart even with the correct stuff removed, i.e. bolts holding case together, front driveshaft flange and shifter.

 

Got it! Had to stand up on the work bench and lift up.... too heavy to wiggle out I guess...
Thank you EST... I (in a man way) love this TW community!

As far as my front ADD: about 6-9 months back I actually bought a (Dorman - I think) replacement - on the hope and prayer, that the front ADD was my issue, and even opened that up to soder the connections, and found that they come sodered that way now a days, at least from them) and put it back together. I hope it went back together correctly..... And after installing it, of course, nothing worked still - as its been for too long...

I'm not keen to try and put a hose clamp around the axel, but I figured that was the way to go.
Question: Next weekend when I get the swap completed and installed; in the effort of NOT wiring up a DPDT switch, (assuming) the front ADD doesn't work - could I pull it, physically push the shift fork over to the engaged position, physically slide the ring gear collar over on/in the axel tube, reinstall the ADD (now in that engaged position), and then just do the 4 wires jumper under the dash at the ECU.. and call it a day?
Dash lights should work, right?

 

Glad you got it! And if I’m understanding correctly, you would put both the shifter and the ADD to engaged and then just leave it be. Then at the 4wd ecu, unplug the two plugs and jump a couple of wires for dash lights? Yes, that’s essentially exactly what I did, except I just switched the truck to 4hi whereas you’ll be switching the ADD manually.

 

Yes, that is what i'm suggesting doing... by the 4 wire jumper I'm meaning:

Connect 4wd sensor wire (red w/ blue stripe - B 22) to the 4wd light wire (solid red - A 19)
Connect 4lo sensor wire (yellow w/ black stripe - B 17) to the 4lo light wire (brown w/ white stripe - A 11)

If I do this, it "should all work" dash lights should function properly - correct??

 

I honestly don’t remember the wire colors off the top of my head but they’re in the other FJ thread. But yes, there are two sensors on your current t case that will plug right into the FJ case with no modification. This is how the truck knows if the t case is in 2/4 and hi/lo. Then at the ECU you’re jumping four wires together (two from each plug), bypassing the ecu entirely.

One of them tells the truck you’re in 2wd/4wd and one of them when you’re on hi/lo. So the dash lights are essentially linked straight to the sensors on the t case.

 

on the first gens a hose clamp was necessary because they were vacuum actuated and would slide back to the disengaged position without vacuum. These are electrically operated with a worm gear so there’s zero chance of the shift fork moving back unless the motor spins which it won’t once it’s unplugged. You’ll find that if you pull the add actuator and try and slide the shift fork over you won’t be able to because of the worm gear design, you can pull the black cover off and spin it from the inside to move the fork. this will disengage the worm screw which is on the motor assembly and allow free rotation of the shift fork.

 

Yeah, that was my question... I just needed to get it vertical and pull/ wiggle harder. I'm imagining that that will be the best orientation to re-assemble....

And yes, pulled this (flat) FJ Case Ring gear, to swap with my Taco's 6speed MT Tcase's (stepped down) Ring gear... and onto that 22 spline Taco planetary gear set...

 

My update is this, had to delay my Tacoma case pull until, next weekend due to needs of my wife last weekend, but I was able to cut my floor out. I was able to reposition my Original front ADD into the engaged position(toward driver), slid the collar over in the axel tube (toward driver) and reinstalled it all.
I tested by had spinning the front drive shaft and believe it is all functional as should be, now engaged.
I unJack standed it, and took it for a test dive around the block, all good. 4x Lights all blinking... but drove fine.
Then I parked and completed the top glove box wire modification part; pulled the 2-ECU plugs and cut the 4 appropriate wires, connecting the 2 pair together as noted in the threads.
I restarted the truck and have no more blinking lights, so feeling good about the progress.

My only unclear instruction remaining is regarding how to deal with the physical sensors on the cases?
In Post #35 above @EatSleepTacos "But yes, there are two sensors on your current t case that will plug right into the FJ case with no modification." Do the 2 actual sensors on my Tacoma tcase need to be unscrewed from where they are located, on the ADD body, and then physically screw them into the FJ case ?
FJ case has 3 sensors while the Tacoma case appears to have only 2 sensors and the single multi pin pigtail connector, correct? (which by the way - just leave that single multi pin pigtail connector dangling/ tape up, its now useless?)
This is not my pic, but is accurate
Thanks community

 

There are two sensors on your tacoma t case that indicate 2wd/4wd and hi/lo. There are three sensors on the fj case that indicate 2wd/4wd, hi/lo, and neutral.

The sensors on the fj case that I got were cut off at the wires.

What I did was take the sensors out of the tacoma case and swap them into the Fj case. One out of the three sensors on the FJ case was for neutral and I left the snipped wire sensor in that spot to act as a plug.

let me know if this makes sense. It should be clear once you drop your tacoma t case out of your truck.

 

Humm... my FJ case plugs are in pristine condition.... and I actually removed them all (marked where went where) when I split the case. I assumed I had to...

Will I need to splice any thing onto the harness on the truck?
In my hand sketch, #1 is FJ Neutral sensor, you think just leave it alone as it is. Maybe secure the un plugged wire and forget about it.
Then my sketch FJs, #2 4-Low position sensor and #3 4wd position sensor need to swap with the Tacoma's sensors (that are in the electronic ADD housing) ?
Front one to #2 and Back one to #3 or visa versa?