3 speed gears in a 4 speed case

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I am looking for info on putting 3 speed gears in a 4 speed case. The tech info here does not have an article covering that process. Are there any other sites that might have the info or is can anyone here explain the process.

thanks :)
 

woody

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The idler cluster for the 3-speed is narrower than the 4-speed....you need some extra shims to center the cluster. Otherwise it's a bolt in/easy swap.

(take pics...we NEED a writeup on this!)
 
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Actually, it's a very simple change-over. The 4-spd xfer gears are wider than the 3-spd gears, therefore the 4-spd case is wider to accommodate the wider 4-spd idler cluster. Everything else inside the case is identical. Toyota offers the idler shims in varying thicknesses. The 4-spd driveshaft flanges will fit, since both gearsets use 10-spline output shafts. Be sure to use the 3-spd flange nuts (cotter-pin type), since the 4-spd ones are slightly larger, and can work loose.

I installed '69 xfer gears into my '77 case, and using a case stiffener from Don Anway. ::)
 

MD11Fr8Dog

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I am looking for info on putting 3 speed gears in a 4 speed case.  The tech info here does not have an article covering that process.  Are there any other sites that might have the info or is can anyone here explain the process.

thanks :)

Randy, I'm in the process of doing the exact same thing, 67 gears into a 75 case. Need to get the shims from Toyota, don't try NAPA, they'll just tell you to go to Toyota! :-[

I'm also considering using the output shaft from my 75 tcase unless someone convinces me that I can't do it. The front splines are fine, so it looks like I can just use all the stuff from the 4spd for the front - high/low clutch sleeve, transfer output front shaft, speedo drive and driven geers, extension housing and front drive clutch sleeve.

The difference in the widths of the idler clusters are apporx 3.1" for the 3spd and 3.31 for the 4spd. Marlin says the largest shims from Toyota will do the trick!!

67 on the left, 75 on the right!
3sp4spTCase.JPG
 
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Thanks for all of the info and pictures. I think that this the direction that I will take. Now to find a good spare four speed case.

Thanks again
 
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I am new to the whole Landcruiser life. I have had mine for about a year. It is a 66 FJ40. I saw this posting and I was wondering what is the gain of putting 3spd gears in a 4spd case? Thanks.
 

woody

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check the tech links...you'll see the pics and info there. Basically, the older t-cases were a more brittle aluminum and more prone to cracking than the later/softer materials. Switching to a later case with the early/lower gearsets helps increase the survivability of the case.
 

MD11Fr8Dog

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I am new to the whole Landcruiser life. I have had mine for about a year. It is a 66 FJ40. I saw this posting and I was wondering what is the gain of putting 3spd gears in a 4spd case? Thanks.

In my case (pun intended!! :D), the "3 spd" tcase gearing gives me a 2.31:1 reduction verses 1.96:1!
 

Pighead

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I have seen those transfer case id pages, but they were on my old computer that crashed. Thanks for bringing them up.

I was hoping for more specific info on what the shimming was and how to determine what shim you need etc.
 
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get 2 ses of t case idler shims from toyota or sor. I had to use 2 of the thickest shims to get the thrust clearance right in my 77 case. You'll also need the correct input gear. 4 speed trans is 16 splines and I think the tooth count is 31.....Mark(65swb45) has these gears new.
 

76FJ40

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I'm trying to do the same thing using an empty Orion case that I found on Flea Bay. Georg gave me some good input on the difference in idler shaft diameters (1" vs 34mm) so the Smukster was kind enough to make the appropriate bushings for me. Once the bearings arrive from C-Dan I'll be ready to assemble.
 

76FJ40

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So 3 speed gears in an Orion case? What for if you don't mind?

I had a late 3 speed xfr case behind my 4.7 Toybox until I split it in half. It's common to put the 3 speed gears in the stronger 4 speed case so why not put them in the even stronger Orion case? I found the Orion case on eBay for $20 (plus $56 shipping) so I will hopefully eliminate this weak link.
 
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I had a late 3 speed xfr case behind my 4.7 Toybox until I split it in half. It's common to put the 3 speed gears in the stronger 4 speed case so why not put them in the even stronger Orion case? I found the Orion case on eBay for $20 (plus $56 shipping) so I will hopefully eliminate this weak link.



makes sense, just wanted to know...
 

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