|Derek's 07 FJ Cruiser gets cryo treated Nitro 4.88 gears (was 3.73)|
|(65 BIG pics loading)|
|DEC 24 2017|
| Derek's '07 FJ Cruiser has the 4.0 Liter V6 with supercharger that gets it on with 303 HP and 330 ft/lb of torque.|
With all the armor protection and various other add-ons, his rig is weighing in at about 4800 pounds (Stock is 4300).
That and the 315/75/R16 tires (34.6") means that the automatic's 5th gear overdrive is basically unusable.
The solution....replace the stock 373's with 488's......31% gear change will do wonders :)
| After some discussion, it was decided that both front and rear Nitro gearsets should be cryo-treated for max strength.|
A solid gear install....coupled with a cryo visit....will give a very strong and dependable 3rd member.
Cryogenics International (automotive page)
| Both 488 ring/pinions are back from Cryo and this link is specifically for the rear V6 8" build-up so parts are layed out and organized.|
The Nitro master kit has Koyo bearings and an upgraded solid collar will compliment this build.
A link to the front 8" clam regear can be found at the very end of this page.
|The center carrier is on the bench and the old bearings are removed with the OTC-4520 bearing puller.|
|Nitro 488 ring is tightened to 70 ft/lb with blue loctite.|
|Sometimes the sleeve lock compound is used on new carrier bearings that are not as tight a press as they should be and it was used here.|
|Pinion end is stripped down....remove the flange first.|
|The original pinion races did show their wear and abuse. Good that we are changing them out now.|
|Pitting and spalling leads to bad things.|
|New outer race is tapped in.|
|The larger inner race takes more care to start straight and true.|
| No pictures but the 488 pinion was loaded with a .081" shim and new Koyo bearing. |
Then the flange was tightened up only enough to give about 15 in/lb of preload.
|Drive side.....Good...but still a slight shallow condition.|
|Drive side of pinion tooth #1...|
|...and #3. They all show the comet tail tucked into the root of the tooth too tight.|
|Drive side...reshimmed from 081 to 085". Much better. Looks slightly deep now and that is what I shoot for.|
|#1...comet tail not as harshly in the root.|
|#2...kinda looks like the tail is swinging to center.|
|#3...tail looks centered almost.|
| Now that proper depth has been established, the solid collar and the seal can go in. |
The collar took only 3 tries. The seal is a good Japanese seal "THO".
|The center carrier is being installed for the final time. Checking backlash.|
|A final pattern check....Drive looks nice.|
|Coast looks great.|
| Final notes.|
Here's the link for the front 8" clamshell install
CLICK HERE FOR FRONT 8" CLAM