FJ62 Transfer Case Companion Flange Preload (1 Viewer)

[Gimme a 60]

Hi.



I took my Rebuilt A440F transfer case, and put it on my H55F, the swap went well (I hope), but I am confused about the preload and the FSM doesn’t specify well.


What/how do you preload the front AND rear companion flange stake nuts? The FMS says that the nut must be torqued to 94-FT pounds- that seems really high!

But more over, after you torque it to 94 FT pounds, it says to preload check at 6.1 - 10.4 In.-lb or 0.7 - 1.2 Nm


I don’t understand….. I really don’t want to wreck my transfer case…… how can there be a torque spec AND a preload??????

 

[cruisermatt]

It's simple. The output flange doesn't effect the bearing preload. The shim/s under the rear output bearing race do.

 

[Gimme a 60]

It's simple. The output flange doesn't effect the bearing preload. The shim/s under the rear output bearing race do.

Okay…. I still don’t understand.


Do I just torque down the nut to 94 Ft pounds and forget about it? I never changed the bearings or shims.

 

[AirheadNut]

You'll need a torque meter or tiny, beam style torque wrench to check the preload. Basically you're adjusting how much static friction there is in the output shaft bearing assembly, or in other words how tightly the tapered roller bearings are pressed together. Too tight, and they'll get hot and wear out. Too loose, and there will be play and they'll wear out.
The basic procedure is this: assemble the transfer, torque the bearing retainer bolts, then use the torque meter to see how much torque it takes to rotate the output flange. If it is less than spec, you need an extra shim. If it is more than spec, you need to remove a shim. If you haven't replaced the bearings or shims then it is probably fine as-is.
Here's the setup for reference (way over spec here):

 

[cruisermatt]

If it was correct before you shouldn’t have to adjust the shim stack.

 

[Gimme a 60]

You'll need a torque meter or tiny, beam style torque wrench to check the preload. Basically you're adjusting how much static friction there is in the output shaft bearing assembly, or in other words how tightly the tapered roller bearings are pressed together. Too tight, and they'll get hot and wear out. Too loose, and there will be play and they'll wear out.
The basic procedure is this: assemble the transfer, torque the bearing retainer bolts, then use the torque meter to see how much torque it takes to rotate the output flange. If it is less than spec, you need an extra shim. If it is more than spec, you need to remove a shim. If you haven't replaced the bearings or shims then it is probably fine as-is.
Here's the setup for reference (way over spec here):
View attachment 3230660

Thanks this makes sense.

 

[Gimme a 60]

If it was correct before you shouldn’t have to adjust the shim stack.

Yes. You are right. But I’m going to check anyways because the guy who I had rebuild it already made a few mistakes.

 

[AirheadNut]

One other thing I just noticed: in the manual posted above it says to fully torque the stake nut on the companion flange before checking preload, but in the manual I used when I rebuilt my transfer (RM183E) it says to temporarily install the stake nut without the companion flange to check preload before final assembly. I don't think there are any significant differences between the 62 and 70 series transfer cases, so I would hazard a guess that it can be done either way.