T case experts: Early TC/4-sp tranny or 34mm split/4-sp behind 3FE (1 Viewer)

[meatloaf]

In the (long) process of starting to assemble my 75 FJ40...

It came with the tc/4 sp tranny in the attached pictures. I also have a 34mm split case and 4 speed laying around. Which would be better behind a 3FE? Any or much difference? Is the older TC called a 3 speed?

Thanks,
Luis

 

[davegonz]

If you had the cash I'd use the Splitcase and get the parking brake parts from @orangefj45 Georg (if he still has any). But either option should work.

Will you need a new tranny crossmember with the newer 4 speed?

 

[meatloaf]

@davegonz, I talked to Georg on Thursday to order 34mm split case rebuild parts & he was out of these, he was getting them today. As for parking brake, I swapped out the axles for '76. From what I have read, the parking brake drum behind the tc applies up to 1980 trucks, correct?

Do you have an extra tranny x-member?

Thanks@!

 

[davegonz]

Sorry, no crossmember.

 

[samc2447]

To run a splitcase you need a 4 speed from a late 40 or 60 series - 19 spline transmission output shaft

The 4 speed in the 40s until 1980 was 16 spline output.

Early 40 3 speed transmissions had 10 spline output , so the transfercase was 10 spline input - referred to as a 3 speed transfercase

Mixing and matching is possible,, but requires different input gears to match the spline count on the transmission and transfer.

Your easiest course of action is to rebuild the 4 speed transmission and transfercase you have.

 

[meatloaf]

To run a splitcase you need a 4 speed from a late 40 or 60 series - 19 spline transmission output shaft

The 4 speed in the 40s until 1980 was 16 spline output.

Early 40 3 speed transmissions had 10 spline output , so the transfercase was 10 spline input - referred to as a 3 speed transfercase

Mixing and matching is possible,, but requires different input gears to match the spline count on the transmission and transfer.

Your easiest course of action is to rebuild the 4 speed transmission and transfercase you have.

thanks @samc2447, I have two combos a split case/4 speed from a 60, I also have the original 4 speed tranny and 3 speed case that came with the 40

I want to mate either of the two combos to a 3FE and was concerned about one being more reliable than the other. If little or no difference, I think going with the original to the 40 4sp tranny/3sp tc may be easier as far as installation

 

[77mustard40]

Luis, Tucker's old 40 (76) had a 3FE and he used the original gear box and xfer case in that swap. You will need the bellhousing from your old motor to mount the existing tranny-xfer case to the 3FE but otherwise it should go right in without any mods needed. CB's green 40 (78?) had the same setup IIRC. If you go with the later 4 speed and split case, then you will have to mod your rear motor mounts, add a crossmember for the tranny and come up with a parking brake solution to make it work. For what its worth, Georg sells a xfer case kit that reinforces the top and rear cone for the case you have since they are not as strong as split cases. Its two pieces of metal, one is plate steel that goes on the top plate where the shifter is located and a steel ring that fits over the rear cone, comes with hardware and is bolt on reinforcement. I installed his kit on my case when I had it out to replace the clutch in my 40.

 

[meatloaf]

@77mustard40 , Kelly, thank you very much for your message, you just confirmed what needed to hear. After the traumatic experience with my 60, the less mods I need, the better. I will contact Georg to order parts, plus the kit you mentioned.

 

[77mustard40]

@77mustard40 , Kelly, thank you very much for your message, you just confirmed what needed to hear. After the traumatic experience with my 60, the less mods I need, the better. I will contact Georg to order parts, plus the kit you mentioned.

I'm pretty sure I got it from Georg

 

[77mustard40]

Here's the old thread on Tucker's 3FE

3FE adventure -

I've had an '89 3FE I picked up for $200 sitting in my garage on a stand for over a year, guess it's time to do something with it. Didn't really plan on swapping out a perfectly good 2F, but the deal was too good to pass up and mine didn't have domed pistons to swap just the top end. So last...

forum.ih8mud.com

 

[meatloaf]

That thread is what I will be using as a guide for the 3FE.

I need to make the brake lines before I put drive train in

 

[davegonz]

On my old FJ55 OM617 conversion, I used the old bell housing mounts to locate the engine and welded in the motor mounts. I then decided to use an H41 from Lee @Sea Knight (better first gear for the diesel) and a split-case. I then created a new tranny cross member for the H41 and removed the bolt-on bell housing mounts from the old setup. Sort of an incremental approach to upgrading to the newer tranny/t-case. I bought the split-case parking brake set-up from @joekatana . That was years ago though and might not have any now.

 

[bottombracket]

Not to add fuel to the fire, but I do know that Georg has just gotten a large number of the split case parking brake output shaft retainers, the pink unicorn part, plus the output shaft and brake drums. He has all the parts in stock needed to put a parking brake drum on the back of a split case now.

I also just picked up a three-piece crossmember that just might fit what you need……

 

[meatloaf]

Thanks Galen!

I communicated with Georg yesterday... in order to keep things simple, I decided to just go with current 3 speed case, ordered rebuild kit for such and will sell off split case.

 

[davegonz]

Not to add fuel to the fire, but I do know that Georg has just gotten a large number of the split case parking brake output shaft retainers, the pink unicorn part, plus the output shaft and brake drums. He has all the parts in stock needed to put a parking brake drum on the back of a split case now.

I also just picked up a three-piece crossmember that just might fit what you need……

Hold on to that. Future 40 diesel swap might need it.

 

[bottombracket]

I have two 3 piece crossmembers...One is from a 40 series for sure, the one I just picked up I am not so sure about. Plus I have the Crushers kit which has one as well.

Minor hoarding here. Luis, I bet I have a spare you could have if you needed one. The 4 speed/one piece t case is still probably an easier option.

 

[meatloaf]

Minor hoarding here. Luis, I bet I have a spare you could have if you needed one. The 4 speed/one piece t case is still probably an easier option.

Thank you Galen! I will keep it in mind.