3 Speed T-Case to 4 Speed Transmission ?

[Skreddy]

Here’s some pics of the FSM.

 

[Skreddy]

If I remember right, your measuring where circled. It’s pretty understandable when it’s in front of you. I think….

 

[Living in the Past]

Worn output shaft splines are super common, but typically only on the 16-spline units ( like this one ) and the 19-spline version in the automatics.
You’ll also see considerable spline wear in the input gear.

Well aware of the 16 spline four speed..Do you think the 19 spline automatic has to do with the shorter spline length on the automatic or just the automatic itself?

 

[Steamer]

Thanks for for the info Skreddy. That'll be the next step. Just having lunch and then I'll put the puller on it to separate. The spacer just slid off and I see no rust so far so that's encouraging.

 

[Steamer]

Well, this output shaft looks much better than the other one. The discoloration makes it look worse than it is. When I slide on the new transition gear, I can just barely detect the slightest of play, but it seems the same amount anywhere on the shaft and no more sitting where it’s going to be. So, I think it’s a go with this shaft and we’ll study Skreddy’s info tonight & do some more checking tomorrow on the inside stuff. The gear stop has some wear on the ends but I'll have to read up to see if it's useable or not.

This t-case had the PTO spacer instead of the gear, so I now have the option to use a gear or spacer in the 3 speed case. That's a reflection and not rust in the pic.

 

[Steamer]

I understand the principles of what synchronizers do but have never seen how they work so I need to get this straight in my head so I can understand the measuring procedure shown in the manual.

So, if someone can confirm whether or not my thinking is correct, it sure would help.

I am thinking that surface “A” is where the friction and wear takes place when gears are being meshed together. Surface “B” is where one side of the feeler gauge touches when measuring the gap between it and the gear.

And so, the smaller the gap means more wear and the bigger the gap is, the better.

Also, is it ok to do these measurements with the gears in place inside the case without disassembling as shown in the manual?

 

[Steamer]

So if the post above is correct, I’m measuring 0.048” & 0.50” on the 3rd & 4th gear syncro gaps which is within the limit of 0.031”.
I sure hope someone confirms I'm doing this right. Big learning day today.

 

[Steamer]

And moving on to 1st & 2nd gear syncros, I’m assuming that the tapered syncros “A” move into the tapered part of 1st & 2nd gears “B” and the surface of “A” is where the friction and wear occur. And so, the bigger the measurement the better.

And here are my measurements for 1st & 2nd gear syncros.

 

[FJ45 67]

i am preparing to swap out my noisy old J30 for a noisy H41, can anyone confirm that the gear selector and hi-lo stick are in the same position ? I know the H41 is 85mm longer and a much larger box.

 

[Living in the Past]

i am preparing to swap out my noisy old J30 for a noisy H41, can anyone confirm that the gear selector and hi-lo stick are in the same position ? I know the H41 is 85mm longer and a much larger box.

The H41 and H42 share the same location on the transmission hump. The J30 three speed the transmission shift cane is in a different location. Because the transfer case is not shifted directly by the lever thru the floor there are more options of locating that shifter.

 

[FJ45 67]

The H41 and H42 share the same location on the transmission hump. The J30 three speed the transmission shift cane is in a different location. Because the transfer case is not shifted directly by the lever thru the floor there are more options of locating that shifter.

Yeah, my research so far is telling me that the 4spd shifter is more to the left a couple of inches , the 'lets have some fun stick' location looks ok and might work although its a different shape cutout to my original. I dont want to cut my original hump, might be time to find a replacement one for this conversion ?? thanks for your input man

 

[Living in the Past]

Yeah, my research so far is telling me that the 4spd shifter is more to the left a couple of inches , the 'lets have some fun stick' location looks ok and might work although its a different shape cutout to my original. I dont want to cut my original hump, might be time to find a replacement one for this conversion ?? thanks for your input man

If running a pre 9/72 transmission cover it's not as tall as the 9/72-1/79 transmission cover. Four speed are taller. Original covers do work but not as much clearance. I used a later four speed cover when I installed an H42 in my 68 FJ40. Need to mold the right side to fit the tub lines. Plus the back needs to be trimmed because floor is different. But holes fit perfect as well as the factory boots.