Kenny's 97 FZJ80 gets 3.55 gears from Australia
(83 BIG pics loading)
Jan 18 2026

Kenny's 97 is pretty much being rebuilt from the frame up. The diffs were only a small part of it...brakes, auto tranny, and even the engine are being rebuilt. A diesel will be replacing old gasoline engine hence the reason for the 355 gears.
This is the stock 4.10 rear 3rd. I will be salvaging the two 30 spline sidegears.......
...and putting them in place of these 32 spline sidegears (100 series center diff shown). Effectively, Kenny's rear 3rd will now have 100 series 3.55 rear gears with a 100 series center differential with 80 series 30 spline sidegears.
80 series sidegears on left....100 series on right. There appears to be slight differences between them.
100 series center case is taken apart and 80 series sidegears go in.....
Backlash is measured between sidegear and the spiders. I noted about .060" and that needs to be closer to .002~.008" per factory specs. Adding a .040" shim to each sidegear solved that issue.
The 8 case bolts were torqued to the exact place as before.
This is the alignment "divot"....the case halves are clocked just like before.
This is the problem with 100 series gears in an 80 series center diff...total mis-alignment and totally different bolt pattern.
101 ft/lb and red loctite on all 12 ring gear bolts.
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You want bearings that are dimensionally correct and last more than 2 years? Then get Genuine Toyota part number bearings. Some of the aftermarket bearing kits are "not right".
There is so much more beef between the 4 pinion 100 series and the 80 series stocker.
This is probably the original 1997 seal...appears to never have leaked...amazing.
Old pinion races removed and the 3rd is cleaned up.
Genuine pinion bearings will go in. A new 32 spline flange was required because the pinion splines were the massive 32 splines. This 32 spline flange can be had at Cruiser Outfitters.
Let's start with a starter shim of .052"
200 series pinion bearings offer the correct fit for the solid collar supplied.
052 drive side ok
052 drive reverse painted. These gears are "blackish"...they appear to have a black oxide coating. Some say that the black ozide helps during the 500 mile break-in procedure. These are still rough gears....90% done.
052....drive side of pinion tooth.
052 coast slight heel which is very common.
052 coast reverse painted.
Here's what it looks like with the collar in place.
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Let's try a little thicker shim to help the pattern go deeper in.
.055"
.055" driveside
.055" drive reverse painted not bad
055
055
055
055 coast
055 coast reverse painted
055 coast on pinion....just taking some extra shots.
055
055
Now trying a thicker shim 058" drive...good looking but the backlash had to be .013" to prevent the pinion teeth from contacting the root of the ring gear and locking up the rotation.
058
058
058 coast
Now going to a much thinner shim to see what too thin looks like and this would be it. Driveside...it is too thin and shallow looking.
.049" too thin....too shallow.
So, looking at the recorded range of 049 up to 058 and also had to consider the backlash issue, 053 was a good balance. 053 resulted in .009" backlash.
The solid collar was dialed in after 4 tries. Genuine factory seal is tapped in.
The pinion nut was really cranked on til 14 inch/pounds of pinion preload was measured. Ding! the dimple and this end is done.
For this install, the backlash was recorded from every tooth...a total of 39 measurements. The residual pattern shown in the above pic is with .049" (too thin).
Drive side....Here's the final patterns with .053" shim and .009" backlash.
.053" coast side
Data is inscribed on the ring gear....they blurred out some of the info on the ring.
Final notes from the rear 9.5" 3.55 install.
The front 8" install is more "abbreviated". Mostly painted patterns. .075" driveside.
075 coastside
075 driveside on pinion
075 coastside on pinion
077 driveside
077 coast
077 drive on pinion
077 coast on pinion
080 on driveside
080 on coast
080 on drive of pinion
080 on coast of pinion
083 on drive
083 on drive reverse painted
083 on coast
083 on drive of pinion
083 on drive of pinion
083 on coast of pinion
.0847" drive
.0847" drive reverse painted
.0847" coast
.0847" drive of pinion
.0847" coast of pinion
The markings on the ring.
This front install also gets a solid collar. Only 2 tries at the shim was needed.
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New factory seal 29 spline.
A little bit of inscribing.....
Final notes of the front 3.55 install.