1972 F motor to 4 speed transfer case?

[Deep South Cruisers]

Trying to help my friend that realized he had missing pieces from his rebuild that stopped him in his tracks. He's got a 1972 FJ40 and the F motor is rebuilt and he bought a 4 speed transmission to switch it over. WHAT transfer case will work with this setup and does anyone have one for sale???

Any help is appreciated! He's neck deep and needs some assistance.

 

[ibinazbass]

He can use either the 4 spd transfer case that would have come with that transmission or the transfer case that came with the truck originally. The earlier model transfer case has a lower low range so many wheelers like that combo. He will need an adapter to run the early 3 speed transfer case with the 4 speed transmission. Commonly sold by advance adapters.

 

[Deep South Cruisers]

He has a 3 speed case with the adapter. We need a complete 3 speed transfer case in the South!

 

[73FJ40]

He can use either the 4 spd transfer case that would have come with that transmission or the transfer case that came with the truck originally. The earlier model transfer case has a lower low range so many wheelers like that combo. He will need an adapter to run the early 3 speed transfer case with the 4 speed transmission. Commonly sold by advance adapters.

You will also need a new bearing, seal, and pto spacer.

 

[Living in the Past]

You will also need a new bearing, seal, and pto spacer.

Plus the

 

[Living in the Past]

You need different bolts to mount the transfer case to the transmission no matter which T case you use. Threads are different between the three speed and the four speed. Driveline will need to be resized or replaced. Four speed is just at three and half inches longer.

 

[3_puppies]

are you sure it is a pre 1981 model year 4 speed?
if it is a split case 4 speed it won't work with a 1 piece transfer case.

 

[Jdc1]

4 speed trans won't bolt up to 3 speed bellhousing.

 

[Living in the Past]

are you sure it is a pre 1981 model year 4 speed?
if it is a split case 4 speed it won't work with a 1 piece transfer case.

Easiest way to check is pre 8/80 has sixteen splines while later has nineteen splines.

 

[Cleg]

What you are describing is the same setup I have in my 72.
It has been a few years since I did the work so I could be leaving something out.
The later model parts on mine came from a donor 1978.
Here it is listed by component.
Cruiserheads please chime in to correct anything I have wrong.

Engine. 1972 F motor.

Bell housing.
Later bell housing to accept 4 speed transmission.

Flywheel.
Pretty sure this was also from the 2f engine and used a later model clutch kit to match.

Transfer case.
Choice of using a transfer case originally matched to the 4 speed or using the t-fer case from the 3 speed and purchasing an adapter.
The t-fer case from the 3 speed that I had was in great shape so I used it with an adapter. It results in a very low-low range.
Easy swap of the input shaft gear and a spacer bushing where the PTO gear would be.

Here it starts to get a little more complicated.

Shift Linkage.
4 speed trans matched with shifter linkage for t-fer case from 3 speed.
This involved making a bracket to shift the mounting points for the shifter assembly.

Cross member.
Cut & move cross member behind transfer case.
The 4 speed trans is about 3 inches longer than the 3 speed.
The longer assembly puts the parking brake assembly right up against a cross member on the frame.
The cross member is welded in place so must either be cut and rotated back for clearance and re-welded.
I found it was easier to cut the cross member off and fabricate flanges for the ends to bolt it back in place.
The frame rails angle out towards the back of the truck.
Cutting the cross member flush with the rails then welding 1/4" plates on the ends made it the right width to move it back.
I did this with the tub off of the frame so it took a few hours but was not that difficult.
I expect that doing this from under the truck with the tub in place would be a B#@tCh.

Drive shafts.
Since your transmission is 3" longer, your drive shafts will now be the wrong length.
The rear shaft has to be shorter and the front one needs to be longer.
Later model drive shafts that were made for the 4 speed are the correct length but the flanges will not bolt to the 3 speed transfer case or the earlier differentials.
Bolt centers on the flanges were changed when the 4 speed was introduced.
If you are using any of the earlier model pieces, transfer case or axles, you will probably need to adapt the flanges to match.

Parking brake.
Studs on the parking brake drum match the driveshaft flange so these were different 3 speed to 4 speed.
Depending on what pieces you are trying to use, a correct vintage parking brake drum can factor in to making it all fit.

 

[Jdc1]

What you are describing is the same setup I have in my 72.
It has been a few years since I did the work so I could be leaving something out.
The later model parts on mine came from a donor 1978.
Here it is listed by component.
Cruiserheads please chime in to correct anything I have wrong.

Engine. 1972 F motor.

Bell housing.
Later bell housing to accept 4 speed transmission.

Flywheel.
Pretty sure this was also from the 2f engine and used a later model clutch kit to match.

Transfer case.
Choice of using a transfer case originally matched to the 4 speed or using the t-fer case from the 3 speed and purchasing an adapter.
The t-fer case from the 3 speed that I had was in great shape so I used it with an adapter. It results in a very low-low range.
Easy swap of the input shaft gear and a spacer bushing where the PTO gear would be.

Here it starts to get a little more complicated.

Shift Linkage.
4 speed trans matched with shifter linkage for t-fer case from 3 speed.
This involved making a bracket to shift the mounting points for the shifter assembly.

Cross member.
Cut & move cross member behind transfer case.
The 4 speed trans is about 3 inches longer than the 3 speed.
The longer assembly puts the parking brake assembly right up against a cross member on the frame.
The cross member is welded in place so must either be cut and rotated back for clearance and re-welded.
I found it was easier to cut the cross member off and fabricate flanges for the ends to bolt it back in place.
The frame rails angle out towards the back of the truck.
Cutting the cross member flush with the rails then welding 1/4" plates on the ends made it the right width to move it back.
I did this with the tub off of the frame so it took a few hours but was not that difficult.
I expect that doing this from under the truck with the tub in place would be a B#@tCh.

Drive shafts.
Since your transmission is 3" longer, your drive shafts will now be the wrong length.
The rear shaft has to be shorter and the front one needs to be longer.
Later model drive shafts that were made for the 4 speed are the correct length but the flanges will not bolt to the 3 speed transfer case or the earlier differentials.
Bolt centers on the flanges were changed when the 4 speed was introduced.
If you are using any of the earlier model pieces, transfer case or axles, you will probably need to adapt the flanges to match.

Parking brake.
Studs on the parking brake drum match the driveshaft flange so these were different 3 speed to 4 speed.
Depending on what pieces you are trying to use, a correct vintage parking brake drum can factor in to making it all fit.

To add to Cleg, you can use the earlier (late 74 to 78ish) 4 speed bellhousing with the engine mounts and pick up your 1F frame mounts to reduce fabbing a rear crossmember. The existing crossmember on the 72 frame might interfere with your parking brake due to the extra length of the 4 speed.

 

[Living in the Past]

It's tight but four speed will fit without removing or modifying the torque tube behind the T case. I also used early four speed T case shifter which is the same style as the three speed with a few different parts.

 

[Jdc1]

It's tight but four speed will fit without removing or modifying the torque tube behind the T case. I also used early four speed T case shifter which is the same style as the three speed with a few different parts.

1976 4 speed and transfer. No mods to torque tube.

 

[CHCP]

1976 4 speed and transfer. No mods to torque tube.

View attachment 1450552

What's that?...armored brake line? I tried to have my past mechanic install armor on my brake lines and he would not do it. Saying that moisture would sit in the armor and rust the lines quicker. off course maybe under your armor is stainless?

 

[Jdc1]

What's that?...armored brake line? I tried to have my past mechanic install armor on my brake lines and he would not do it. Saying that moisture would sit in the armor and rust the lines quicker. off course maybe under your armor is stainless?

It's rock guard with Nicopp lines. Supposedly they won't rust. Time will tell.

 

[Xpnsv72fj]

He has a 3 speed case with the adapter. We need a complete 3 speed transfer case in the South!

I've got a 3 speed trans and transfer case siting on my garage floor taking up space you guy can have cheap, I'm in VA.

Josh

 

[CHCP]

It's rock guard with Nicopp lines. Supposedly they won't rust. Time will tell.

Oh yah, I know what you're talking about comes in a roll instead of straight pieces. I had a M 37 Dodge power wagon before my land cruiser and it had the spring rock guards on all lines described as "armor" in the manual.

 

[MrHyde]

1976 4 speed and transfer. No mods to torque tube.

View attachment 1450552

Just dropped the motor in my son's '72 last night and saw how close the torque tube is to the P-brake. How would you ever service the pads in the future? It does not look like the drum can come off without really tilting the engine up off the front mounts.

 

[Jdc1]

Just dropped the motor in my son's '72 last night and saw how close the torque tube is to the P-brake. How would you ever service the pads in the future? It does not look like the drum can come off without really tilting the engine up off the front mounts.

That’s the plan. I installed brand new shoes and hardware in mine, hopefully it won’t need to be serviced for a long time.