Switching from vacuum to mechanical transfer case engagement (1 Viewer)

[Dirtygumboots]

I’ve searched and looked at the FAQ with no luck so I’m looking for help and opinions. I have a 1971 and I’m considering switching to mechanical engagement on the 3 speed t-case.

Can you just switch the mechanical shifter off a 73 or do you have to switch the case?

Again any help would be appreciated.

 

[DesertFJ40]

I've never done it as I have a 71' vacuum activated t-case. Stumbled across this a while back, perhaps you can go This route

YWST: Vacuum T-Case to Manual Shift Conversion Kit

 

[Dirtygumboots]

Thanks. I did see that one. I picked this up for the parts and now I just need to sort out to connect it to my SM465 tranny.

 

[Living in the Past]

I've never done it as I have a 71' vacuum activated t-case. Stumbled across this a while back, perhaps you can go This route

YWST: Vacuum T-Case to Manual Shift Conversion Kit

This kit is for the split transfer case that didn't start until 8/80. On the early one piece transfer case it requires unbolting the vacuum actuator and bolting the manual shifter on.

The biggest issue using a SM465 is there is no boss on the transmission housing for the transfer case shift linkage.

 

[Downey]

Take a gander at ebay #253408224861, or #263314206086, or #263909718693.

 

[65swb45]

I’ve searched and looked at the FAQ with no luck so I’m looking for help and opinions. I have a 1971 and I’m considering switching to mechanical engagement on the 3 speed t-case.

Can you just switch the mechanical shifter off a 73 or do you have to switch the case?

Again any help would be appreciated.

Shifters are interchangeable. As stated, you will need to fab a mount for the shifter pivot pin if you're using a non-Toyota trans.

 

[Living in the Past]

Shifters are interchangeable. As stated, you will need to fab a mount for the shifter pivot pin if you're using a non-Toyota trans.

Not sure the length of a SM465 so not sure if the J30 three speed or H42 four speed linkage is a better match. I assume when you use the four speed 4WD acturator the rod running back to the high/low shift lever increases in length to match the longer transmission? My guess (which is just that) is with a V8 the three speed 4WD acturator would probably work better to keep the transfer case lever closer to stock location.

 

[Rock40]

Your original post reads like you're using all Toyota parts, you just want to swap to mechanical shift right? If that's the case, it's a bolt on affair and you can use your original transfer case just fine. I'd pull the tunnel cover for access. On the transfer case itself, the main part that needs to be swapped is the 4WD mode shaft housing which is held on by 4 bolts. The rest is just shifters and linkages. The threaded boss in the side of your 3 speed transmission is probably full of junk and grease and it's usually a good idea to thoroughly clean it out and run tap into it.

 

[Dirtygumboots]

@Rock40 you are right my first post was vague. I picked the 73 trans and transfer case basically for the 4WD mode shaft housing to replace my vacuum system. I need to mate this all to my SBC with a SM465. Some people seem into the vacuum system but after 47 years of being it use I feel like a mechanical system might be better. I have lockrite lockers front and rear so I'm considering the advanced adapter twin sticks so I can pull it out of 4wd and still have it in low. If anyone has experience with this set up I'd appreciate hearing about it.

 

[Downey]

Dirtygumboots, look at the photo in post #3 above. By not using the top guide plate that the lever is protruding up through you can use low range without being in 4WD, but when you do that you have to respect what you are doing because you are putting twice as much torque on the rear pinion gears only, easy to break if you unload too much power too quickly.

 

[65swb45]

Dirtygumboots, look at the photo in post #3 above. By not using the top guide plate that the lever is protruding up through you can use low range without being in 4WD, but when you do that you have to respect what you are doing because you are putting twice as much torque on the rear pinion gears only, easy to break if you unload too much power too quickly.

IOW, just because you can, doesn’t mean you should.

 

[Dirtygumboots]

Downey thanks for the info. That isn't something I had considered as I'm new to all this.

 

[Rock40]

OK, I'm with you now. I have been running an Advance Adapters twin stick for 14 years now and it's been great. I'd go that route as the install is clean and simple. I'm running a similar setup to yours, SBC, SM420, Rockbox (now discontinued) and stock transfercase.

As for running around in 2WD low, I never had any issues with it regarding the pinion gear. That was just my experience though when I still had the stock FJ40 rear axle.

 

[69LC]

I too modded my stock L-pattern to a square. I pulled a lot of heavy stuff around in 2-low with a sbc and 35s. The pinion was just fine.