Running rear wheel bearings in diff oil. (1 Viewer)

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surfari-LC80

surfari-LC80

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Mar 26, 2008
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saw this and wanted to see what mud thinks of this? risky modification or a decent idea?

Edit: I dont know if the link i posted is working. its a facebook video from Feb. 2018 by madmatt4wd. title is "Why I run my wheel bearings in oil and a heap of other tips I’ve found out." its on a 80 rear with the axle seal left out, oil resistant sealant instead of gasket on axle to hub flange, overfilling diff oil via breather etc...
 
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I haven't done it on an 80, but it makes sense...most other full-float rear axles run oil-bath bearings instead of grease.

I did run across this comment though:

Tools R Us said:
We usually remove the inner axle seal, run the bearings on gear oil, reducing maintenance to an occasional play check, if needed preload set.
Click to expand...
 
Well his "choice" to delete rear seals is kind of something the 80 makes for you. new seals let oil leake by no matter how you try to seat them.
 
Discussed a good bit in other threads on the forum. @Tools R Us has posted on this as mentioned above. I've been running with no inner seals in the rear axle for about a year with no issue and preload has held also.
 
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Educate me. Is this a solution for a common problem? Don't read too many threads on rear bearing failure / issues.
 
@Cruzerman Others have a lot more knowledge/experience on this topic and most of mine is second hand but I'll share my take on seal w grease vs. no seal w gear oil in the rear hubs.

As you note, rear bearing failures aren't that common with the seal/grease setup. In the long-run, if the seal(s) fail then gear oil cycles through anyway meaning that the bearings are pretty unlikely to run dry. I went with the no-seal, gear oil in the hub option not to try to avoid bearing failure but for the following reasons:
  • assembly was easier as I didn't have to install the new seals and pack the bearings
  • service is easier since replacing the lube in the hub bearings will happen when I drain/refill the center diff
  • gear oil is arguably a better bearing lube than grease but either way fresh lube is better than old and given the easy service the gear oil will stay fresh
  • most full float rear ends run this way apparently so it's a proven option
My main hang-up was asking myself why Toyota chose the seal and grease option as I like to go stock unless there's a good reason not to. I didn't really find an answer to Toyota's logic on this so the benefits above won out and I've not had any issues in the year and 10k+ miles I've driven without the seals/grease.
 
Thanks for the explanation. Looks like I may be running this way and not even know. Guess I'm going with the "do nothing" option for now.
 
My concern would be if you ever have to run without axle shafts because you broke something offroad. The benefit of grease is you can run without a axle shaft. If you broke a axle shaft and were worried about shrapnel in the differential moving around and killing the 3rd member, with grease you can just pull the drive shaft and axle shafts, and drive out in front wheel drive.
 
RFB said:
Sarcasm??
Click to expand...
Nope, not sarcasm. Hard wheeling, big tires and lots of miles means I chew through bearings about as fast as our austrailian friend. This is an interesting solution that is so simple I can't believe I didn't think about it sooner.

White Stripe said:
My concern would be if you ever have to run without axle shafts because you broke something offroad. The benefit of grease is you can run without an axle shaft. If you broke an axle shaft and were worried about shrapnel in the differential moving around and killing the 3rd member, with grease you can just pull the drive shaft and axle shafts, and drive out in front wheel drive.
Click to expand...
You could still do that without the seal... (I don't think I've seen a broken 80 series rear axle shaft that wasn't just straight abused on, like I'm talking ignorant levels of thrashing)
 
jpoole said:
@Cruzerman Others have a lot more knowledge/experience on this topic and most of mine is second hand but I'll share my take on seal w grease vs. no seal w gear oil in the rear hubs.

As you note, rear bearing failures aren't that common with the seal/grease setup. In the long-run, if the seal(s) fail then gear oil cycles through anyway meaning that the bearings are pretty unlikely to run dry. I went with the no-seal, gear oil in the hub option not to try to avoid bearing failure but for the following reasons:
  • assembly was easier as I didn't have to install the new seals and pack the bearings
  • service is easier since replacing the lube in the hub bearings will happen when I drain/refill the center diff
  • gear oil is arguably a better bearing lube than grease but either way fresh lube is better than old and given the easy service the gear oil will stay fresh
  • most full float rear ends run this way apparently so it's a proven option
My main hang-up was asking myself why Toyota chose the seal and grease option as I like to go stock unless there's a good reason not to. I didn't really find an answer to Toyota's logic on this so the benefits above won out and I've not had any issues in the year and 10k+ miles I've driven without the seals/grease.
Click to expand...

I disagree with your one statement of:
"* service is easier since replacing the lube in the hub bearings will happen when I drain/refill the center diff"

The oil in the wheel bearings will NOT be replaced when you drain and refill the differential. There is NO drain or flow bypass for the oil from the spindle to return to the differential. Once the oil has flowed outward into the wheel bearings, it is there until it leaks out of the hub seal. Yes, there will be a SMALL amount of mixing at the tip of the spindle, but it will NOT be "refreshed" just by doing a differential oil drain.

Otherwise, it does not appear to be harmful to run them in gear oil, as all the Dana 60+ full float rear axles on Chevy, Dodge, Ford all run gear oil in the wheel bearings.
 
SmokingRocks said:
Nope, not sarcasm. Hard wheeling, big tires and lots of miles means I chew through bearings about as fast as our austrailian friend. This is an interesting solution that is so simple I can't believe I didn't think about it sooner.


You could still do that without the seal... (I don't think I've seen a broken 80 series rear axle shaft that wasn't just straight abused on, like I'm talking ignorant levels of thrashing)
Click to expand...
Without the seal? How would that work? Im thinking if the axle shaft is not in the hub, the bearings will not get any oil from the axle housing, whatever oil is in the hub will get flung out after a short time and become starved of lube since the shaft caps the end of the spindle. Not saying it would be a common need to run without a axle shaft, but just a benefit of having grease over oil. Axle shafts fatigue over time similar to a sway bar from lots or torsional cycles. Once a shaft is fatigued it can break easily. Pinions can do this too.
 
You don't carry a tube of grease in your kit? I do.... Along with a set of replacement bearings... Just kind of one of those things most 80's owners who wheel regularly ought to carry, along with knuckle studs, fusible link and perhaps an extra unbent rear lower control arm
 
White Stripe said:
Without the seal? How would that work? Im thinking if the axle shaft is not in the hub, the bearings will not get any oil from the axle housing, whatever oil is in the hub will get flung out after a short time and become starved of lube since the shaft caps the end of the spindle. Not saying it would be a common need to run without a axle shaft, but just a benefit of having grease over oil. Axle shafts fatigue over time similar to a sway bar from lots or torsional cycles. Once a shaft is fatigued it can break easily. Pinions can do this too.
Click to expand...

The axle shaft does not cap the spindle. Remember, the spindle is stationary. The axle shaft rotates.
 
BILT4ME said:
The axle shaft does not cap the spindle. Remember, the spindle is stationary. The axle shaft rotates.
Click to expand...
I believe what @White Stripe is concerned about is the fact that the gear oil will be flung out and the bearing would dry out and fail.

That's a reasonable thing to worry about. So here's how I would handle it if I was running greaseless:
  1. Axle shaft breaks
    • Remove axle shaft, plug spindle
    • Pull the hub and pack the bearings with the tube of red tacky that I keep in my trail repair kit
    • reassemble
      • remove the rear driveshaft and other axle shaft if required.
    • drive on.
 
BILT4ME said:
it is there until it leaks out of the hub seal
Click to expand...

I didn't install the seals. You are correct that it won't fully drain out but the fresher gear oil from the diff will cycle through and keep the oil in the hubs fresher with this setup that runs no inner axle seals to keep the oil out of the hubs.
 
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