Transfer case gear mesh question (1 Viewer)

[DesertFJ40]

Good day/evening to everyone

I recently did a 4-speed transmission swap into a 1971 fj40. Its an early style h41 and im re-using my original 3-speed transfer case. Nothing was rebuilt on the t-case. There are a bunch of different variables in all of this, but to sum it up as quickly as i can, i began getting a noise when i let off the gas. It sounds like a rough bearing spinning. When I accelerate, the noise goes away. It sounds like a low scraping noise that you often get if you spin a worn bearing by hand. So i began investigating. I popped the PTO cover since I had a hunch something was off in there. In my mind, my concern was with the spacer that gets sandwiched in-between both the trans/t-case and thinking that, somehow, it was spinning freely in place while driving or that the drive gear wasn't aligned correctly. I did not have the original spacer to the transmission, so I bought a used 19-spline 4 speed transmission spacer to work. Here is a diagram picture of that spacer:

Well now my big question is this. Inside the PTO access port, you can see the gears inside of the transfer case. The way the top Transfer input gear meshes with the bottom gear seems off to me. Ive come to the conclusion that the spacer might have been a tad too long and caused the input gear to be pushed a bit more in one direction that what is "normal". How do you guys think the best way for these gears to mesh should be? This first picture shows my current set up. As you can see, the top gear sits a tad over to the right in correlation to the bottom gear:

I also just recently acquired another 4 speed transmission and t-case. I looked inside and now the gears are meshed differently too! The top gear sits more to the left in correlation to the bottom gear

Here is one more picture. This was my 3-speed transmission and 3 speed transfer before I separated them. The top gear sits a bit more to the left, but not as much as the the one from the picture above. I think in an ideal set up, the gears should be aligned perfectly. Not too much to the left or right. Just meshing correctly and centered to each other. Is there any issue in running with how I currently have it set up? Thank you guys for your input and thoughts. I don't think this will resolve the low scraping noise that im hearing, but just trying to trouble shoot that noise opened up a new can of worms to worry about.

 

[rkymtnflyfisher]

Regarding your thoughts on that spacer.


@orangefj45 posted this in my build thread after I had a question about it.

Looks like you already have your answer.

More info?!

These 3 spacers were discontinued years ago. Typically they’ve all “spun” just like yours and now so much material has worn away that the nut on the trans output shaft won’t tighten them properly.

Why does that happen?
From the factory, Toyota, used grade 8 washers between the rear spacer and stake nut. Over time, the washers will bent and concave, allowing the spacers to start rotating and wearing out. Toyota has since changed the washers out to a SAE case hardened unit. Of course, we keep these in stock as well.

Good news?
We reproduced these spacers. Started with thick wall DON, machined to size, then case hardened and ground to proper length.

Why?
Because the only way to build one of these transfer cases probably was to have the right parts. So we made them.

Happy to help!

Georg @ Valley Hybrids
Shop 209-475-8808
Sales@valleyhybrids.com

 

[rkymtnflyfisher]

And the gears in my t case weren't lined up perfectly either, the input gear was offset to the left similar to yours.

 

[mrboatman]

Here’s a picture of mine 4 years ago before disassembling

 

[MOTOV8R]

Mine looked about the same. This is an orion gearset and case.

 

[DesertFJ40]

And the gears in my t case weren't lined up perfectly either, the input gear was offset to the left similar to yours.

Hmm, interesting. I went ahead and read that part of your build concerning the spacer. And that spacer is exactly the one im questioning here with my set up. Out of curiosity, did you find out exactly what that spacer was rubbing up against to cause it to wear down on the face of it? And did you end up re-using it? I'm wondering if the one I'm using at the moment is too long and is pressing itself up against the face of the top (input) gear of the transfer case and will eventually cause the same wear as the one from your build.

Here is a link to your build thread in-case anyone wanted to read up on the spacer ( An Accidental Frame Off... )

here are two pictures also showing the spacer that goes at the very end of the shaft sticking out from the back of the transfer. The 1st picture is how it lines up currently in my fj40. unfortunately, the stake nut isn't grabbing by 1 or 2 threads even after torquing it down. Its the older style that uses a thin lock washer with a tab that needs to be bent into place.

This second picture is my new transmission set up. Even though i have the transmission and t-case apart in this picture, everything lined up the same way when they were mated together when i got it. The spacer shown is the same size as the one im using on my fj40. for what ever reason, the spacer and the stake nut go on perfectly and expose a few threads at the end of the shaft. This is exactly how it looked on my original 3 speed before i pulled it apart.

Thank you @mrboatman and @MOTOV8R for the pictures. I'm left scratching my head now. Everyone's transfer case, so far, all show the top gear being slightly more to the left compared to how im currently driving mine. And does it really affect anything internally? It all seemed to spin okay. At the moment, i don't want to pull everything out and separate the drive train just to get the gears lined up more to the left or perfectly center. To do that i'd need to either pull the engine out with everything from the front or tilt the engine rearward and remove the trans/t-case since my cross member is in the way. Such a hassle. I wish Toyota had made the back of the 4-speed transmissions like the 3-speeds. Those did not have a spacer in the middle and they mated flush with the transfer case. I've read several threads where people forget to install the spacer or, in my case, perhaps ended up with a spacer being too long

 

[peesalot]

Is the spacer you used for a 4spd to splitcase ? Curious where you got the special input gear to mate the 4spd to 3spd case ?

 

[Living in the Past]

Curious where you got the special input gear to mate the 4spd to 3spd case ?

9/73 to 4/75 Toyota used a twenty nine teeth gear with sixteen splines on the four speed.twenty nine teeth is the same as the three speed with ten spline.

 

[charliemeyer007]

Mark had the adapter unit

http://www.marksoffroad.net/1specials/1specials.html

090-05 $180

 

[DesertFJ40]

Is the spacer you used for a 4spd to splitcase ? Curious where you got the special input gear to mate the 4spd to 3spd case ?

I was told that the spacer that i got was off a 19-spline transmission. I believe that style transmission mates up to a split-case. Before ordering, I measured the diameter of output shaft from the h41 and got 35mm. Once I received the spacer in the mail, I re-measured the diameter of the spacer and got 35mm. So its a perfect fit in regards to diameter and it did not have any play when placed onto the output shaft. I was told that perhaps the overall length of the spacer may need to be ground down to fit correctly, depending how everything fit. Since i couldn't find any information as to how long the spacer needed to be, I went ahead and assembled everything together. I noticed that the spacer did stick out a bit from the back of the transmission by what seemed to be a couple of millimeters. I was not sure if that's how it was suppose to be or if it was totally wrong. For the most part, it all fit together. While driving, everything shifts and I can go through all gears without issue.


As far as the input gear. The transmission in my fj40 is an early h41 with a 10-spline output shaft. This is the deep geared h41 that has the 5.3 gear ratio. I bought it from specter off-road back in 2019 and just recently installed it. It did not have a spacer when i received it. This early h41 has the same spline count as a 3 speed. They are both 10-spline output. So everything mates up together with no special gear inside of the transfer case. For the later 4speeds, either h41 or h42, you do need to get a special gear to fit on the inside of the transfercase.

9/73 to 4/75 Toyota used a twenty nine teeth gear with sixteen splines on the four speed.twenty nine teeth is the same as the three speed with ten spline.

Hmm, then maybe the spacer I got was from an early 16 spline? I measured the diameter of the h41 and got 35mm. I also measured the diameter of my 3 speed and got 35mm as well. Maybe the early 16-spline transmissions and the later style 19-spline transmissions have the same diameter.


I went out for a test drive and discovered something new while driving. So when letting off the gas, i still get that light scraping noise. When I push in the clutch all the way, the sound disappears. It also disappears when I shift the transmission into neutral and coast down the road. So now I'm thinking its a worn out bearing inside of the transmission? When the clutch is pressed or while in neutral, what part of the transmission spins? Im thinking the front shaft stops since its being disengaged from the engine. Does the rear of the transmission continue to spin?

 

[Living in the Past]

If the transfer case is not in neutral the back of the transmission will spin with the vehicle moving. What changes the force reversed with the engine coasting with the food off the pedal. Any helical gears the try to move in the opposite direction. If the input gear is trying to move to back when the engine is applying force when the axle is driving the transfer case the force is in the opposite direction.