2f+4 speed from a '79+early vacuum t-case (1 Viewer)

[redleg76]

So, I've got a '65 with all original drive train. The opportunity to drop a solid '79 2F and 4 speed has presented itself. Other than the adapter from tranny to t-case, what is needed? Is there need to cut anything or any cross member issues?

I've read in the FAQ's until I'm crazy.

TIA

 

[Rock40]

You'll need the adapter you spoke about and you'll need to relocate the cross member to the rear a bit. It'll be very, very tight if you don't and you'll likely not be able to get the transfer case in/out of the truck

 

[redleg76]

Thanks for the clarification. I thought that was the case, but I've read so many threads they were running together on me.
Does it need to be relocated, or just cut out (notched)?

 

[Rock40]

It should be relocated to the rear. I'd remove it, mock up the drivetrain and then figure out exactly where it should go

 

[redleg76]

Thanks for the help. What about gas pedal linkage etc... trying to come up with the list of what all I need to make this swap happen.

 

[3_puppies]

you'll have to change some wiring around, oil pressure, ignition/ignitor, alternator it should be internally regulated, fan shroud from a 2f.
if you can get a 4 speed 1 piece transfer, I'd use that versus your 3 speed. IIRCC you only need the input gear, there isn't an adaptor.
Can't remember how I rigged up the throttle linkage on 1 I did 15 years ago.

 

[redleg76]

Thanks for the help!
2F shroud, move the cross member, wiring differences, and input gear change.
Do drive lines stay the same since I'm keeping the original t-case?
Anything else?

Tia

 

[Tancruiser]

You will need to redo the drive lines and I'm not sure the shifter locations are the same .

 

[Tireguy87]

Just went through a similar swap on my '67. I moved and extended my alternator wiring to the passenger side with some wire and material I got from @Coolerman. If you make sure your transfercase is in good working order as well as your parking brake, you can get away with not cutting out the crossmember. However, if you ever need to service anything park brake related or remove the xfer/tranny, it will need to be cut out and relocated. I have about 2" of room.

I opted not to go with the later model fan clutch water pump setup and instead used a regular non clutch pump and plastic fan so that I can keep my same earlier fan shroud.

Also, your front drive shaft will now need to be longer and the rear shorter due to the longer length of the 4 speed. I'm aware of that fact but I haven't gotten around to seeing exactly what I'm going to need to do there.

Make sure you use your early sending units (oil pressure and temp) in the new motor.

I think that's about it. If you have any questions feel free to ask me.

 

[SteveH]

I had to do a 1" body lift on my FJ45 to get the '65 trans. tunnel cover to clear my 4 speed. If the tunnel cover rests on the transmission, it becomes a sound-radiating speaker and it sounds like you have a milling machine inside the cab with you. I could have clearanced the tunnel cover, I suppose, but the small body lift worked great, and was invisible to anyone but a purist.

 

[redleg76]

Thanks so much for these responses. I am definitely learning as I go, with the help of Mud members.
I have a new water pump of the non clutch variety. I think I'll go that route w a plastic fan as well. I am going to cut and move the cross member, just in case. 10-4 on the early sending units, too.

Thanks again

 

[Coolerman]

Four other things you will have to address:
One: If you use the 3 speed t-case with the vacuum shifter, you will have to modify a body support to clear the vacuum shifter. A body lift may solve this.
Two: You will also have to extend the mechanical t-case linkage for the vacuum t-case shifter due to the longer tranny.
Three: If it's possible to get the 4 sp driveshafts with the 2F engine/tranny then you can do this swap without modifying the drive shafts. You will also need the 4 sp t-case emergency brake setup as it has the wider bolt spacing for the 4 sp rear driveshaft.
Four: You will need to get three, coarse spline pinion flanges with the 4 speed bolt pattern. One for the front and rear diff and one for the t-case front output. Kurt at Cruiser Outfitters has these.

I did a write-up on this a while back that may have some additional information for you.
4 Speed Tranny Install
4 sp Install Drive Shafts

 

[redleg76]

Thanks. I knew the splines were different, but have been digging on which I need.

 

[Living in the Past]

To keep the high/low on the dash you will need to keep the clutch slave on the driver's side. You will also need to lengthen the vacuum hoses at the transmission as well as lengthen the rod going from the motor mount to the high/low shift lever on the transfer case.

 

[redleg76]

I will keep clutch master/slave where they are and go to a dual circuit master, non boosted to run the front disc axle. The front axle I have is off a 76, so I'll still need the coarse spline flanges.

With all the changes that have to be done, would going to the 2F and keeping my 3 speed tranny /t-case be a better option? This rig will be driven on pretty weekends, mainly on road. I got a 4 speed with the 2F, and the thought of not grinding gears was intriguing.
This rig is numbers matching '65, and the F motor and ball and claw axle will be cleaned and freshened, shrink wrapped and stored in my shop so I can "go back" to all original.
Thoughts? Suggestions?
I just want a dependable weekend rig that I can get back to all original if the time comes to do that.

 

[Living in the Past]

Thought all disc brakes had fine spline hubs. 76-78 had a longer housing hubs. The four speed is a superior transmission but is a tight fit. First thing I would do is inspect the tailshaft on the four speed. These are known to wear on the spot the transfer case input gear rides. While I've never had one do it the ten spline don't show wear just snap. Worn splines on the four speed the input gear slaps back and forth everytime you step on the gas and off the gas pedal. Didn't modify the frame or tub on my 68 when I installed a four speed. I did put a few extra hole in the floor because I used a later transmission cover that is taller. I switch to a floor shift transfer case so used the correct boots for both transmission and transfer case.

 

[SteveH]

FWIW - I bolted the '65 vacuum shifter mechanism to a 1980 transfer case, and kept my '65 dash shifter and 4WD controls for the transfer case. I did cut a hole in my tunnel for the 4 speed shifter, as there is no way around doing that. So, my dash controls looked at worked as if it were 1965, which was pretty slick.

 

[Living in the Past]

FWIW - I bolted the '65 vacuum shifter mechanism to a 1980 transfer case, and kept my '65 dash shifter and 4WD controls for the transfer case. I did cut a hole in my tunnel for the 4 speed shifter, as there is no way around doing that. So, my dash controls looked at worked as if it were 1965, which was pretty slick.

Just curious how you handled the high/low shift lever? On the earlier dash and floor shift it came with the transfer case lever pointing to the passenger's side frame. 80 it pointed forward. Switching the top plate with the lever and extending the rods three and half inch it could operate off the dash. How did you handle?

 

[SteveH]

I can look for photos tonight, but I suspect I made an adapter that allowed the fore-aft '65 lever movement to properly operate the lever-style 1980 xfer case. I did this ~10 years ago, so my memory is a little fuzzy. I recall that it worked crisply and properly. I did not use an earlier top plate with the xfer case - I ran the 1980 xfer case stock, other than bolting the vacuum shifter assembly to it.

 

[Shark56]

Just curious how you handled the high/low shift lever? On the earlier dash and floor shift it came with the transfer case lever pointing to the passenger's side frame. 80 it pointed forward. Switching the top plate with the lever and extending the rods three and half inch it could operate off the dash. How did you handle?

I switched the top plate when I did a swap in my 9/69. I used engine, transmission and transfer case from my old 1/79 keeping the vacuum shift.
Fyi, on mine I did not move the cross bar. I have pulled my e-brake drum since by loosening the rear motor mounts and removing front. Jack front of motor for access.