Question about T-case Preload. Mine too low? (1 Viewer)

[Bryan062087]

I rebuilt my transfer case last spring and never was able to measure the pre-load on the output shaft bearing as accurately as I would have liked.

Now, I'm having a shop do a transmission swap on my truck and asked them to measure the transfer case preload. Was measured at 12 inch pounds, which is what I remember getting when I rebuilt the case- this measurement is lower than the required 13-21.4 inch pounds for new bearings.

The transfer case bearings have about 3k miles on them since the rebuild. Should the current shim be replaced to get a reading more in the middle range of the specs? Also, since I've put those miles (3k) on the transfer case since rebuilding it, should I go by the new bearing preload specs or used-- which is something lower like 6-10 inch pounds?

Thanks.

 

[Lost]

if theres is no free play in the [rear] output, i thinks you should be fine

 

[Spike Strip]

It's not a new bearing anymore... You should be fine.

I asked the top tech guy at $OR this same question and he said when you rebuild a t'case, just using bearings/races, you're essentially putting it back to "new" spec. He said they rarely have to adj the shim for preload. It had a very wide tolerance from the factory.

I had to replace the output shaft in mine, so it needed to be shimmed to get it into spec.

 

[alaska60]

I think your fine at 12 pounds. So long as there is no slop like Lost said.

 

[CTFJ]

After a rebuild, everything is going to be WAY smoother and result in less friction. Preload as a measurement of overall resistance at the output shaft to overcome inertia, you would expect a lot less after a rebuild.

So yeah, expectedly normal reading there. It would be a problem if it was too high and out of the tolerance range.

 

[hank14]

I'm finishing up my rebuild now. Just wanted to clarify- the FSM says the transfer case is in neutral, right? Meaning, when you turn the rear output shaft, neither the front output shaft nor the transmission turn.

If that's the case, my preload after replacing bearing and seals is too low to read on my inch pound wrench. Thicker shim needed?

 

[Pin_Head]

It isn't that much work to take it out and shim it tighter.

 

[hank14]

No, but I've got no extra shims. Should I order a set?

 

[DrivingMissRosey]

Could be an issue with the device used to measure the preload

What mechanism are you using to measure the preload on the bearing? Is it the fishscale technique similar to the one on the knuckle and wheel bearings? The difference between the preload that you are measuring and the precision of the device could be off that pound and change. Just my two cents, and I'm kind of new to landcruisers so I might not know what I'm talking about.

 

[hank14]

I'm using a inch pound torque wrench like the one in post #3:

https://forum.ih8mud.com/60-series-wagons/261568-question-about-checking-preload.html

You're definitely right that the technique may be bad. I have a 32 mm 1/2 inch drive socket hooked to a 1/2 to 3/8 adapter hooked to a 3/8 to 1/4 adapter hooked to the torque wrench. The whole thing may weigh more than 6 pounds!

 

[LAMBCRUSHER]

on my one piece case, I used a fish scale to measure preload. Put the hook of the scale on an output bolt, and pull while watching the scale. record the preload at the point where the shafts just begin to rotate...

 

[hank14]

OK- I went back through the FSM instructions. It does not say to put the gasket on the output shaft bearing retainer housing when checking preload. It does show using a torque wrench-like tool as shown above.

Also, the output nut it 30 mm, not 32 mm.

After removing the gasket, the preload was higher- around 6 in-lb. Still less than the 13-21 spec for new bearings. I think it will be OK, although the next 2 thicker shims would probably make it just right.