Rear Axle Bearing and Seals--Replacement

[Atazman]

Gents....

I have almost finished changing out my right rear, inner and outer axle seals.  First time for me..... and it was not much fun.  If I have to do it again it will be much easier. 

Anyway, I would like you guys opinion on something.... a change to the well-proven German engineering.  As you know, the axle bearing is located between two seals.  I'm guessing the inner seal is intended to keep gear oil from working it's way into the bearing area.  Then.... the outer seal is to prevent grease/oil from getting out of the bearing and onto the brake system.

Here's what I'm wondering about.  Why not delete the inner seal and allow the gear oil to lubricate the axle bearing??  It seems to me the outer seal would prevent leakage.  Don't know about you, but I prefer oil in that bearing rather than grease lubrication. 

I don't know how long my bearing has been lubricated with gear oil, but there certainly was no grease in it.  Do you guys periodically pull the axles and re-pack those axle bearings?

But....... I did grease the bearing up good, and installed new seals.  I'm a little uncomfortable because I did not use a new lockwasher between the bearing and nut.  Hope it holds!! 

[Raymond]

My, perhaps ill-informed, guess would be that there is far more heat in the bearing than even 90 weight gear oil could withstand.  The thinner viscosity would not provide sufficient lubrication. 

[ja17]

That's my guess also Ray and Atazman.  Grease seems to work best on the front wheel bearings also. But it sure would be simpler if the rears only used the one lubricant.

[Atazman]

Thanks, Ray and Joe.........

What prompted me to wonder about this is that I'm into 4-wheeling and rock crawling (old Toyota Land Cruiser) and I installed full floating axles in the rear about 10 years ago.  These are equivalent to 1-ton Chevy axles, so they are huge.  I had the option of using an inner axle seal and grease in the bearings, or to leaving out the inner seal and lubing the bearings with differential gear oil.  I chose the latter, and have had no problems.

Nonetheless, I greased the Pagoda bearing and hopefully will have it back on the road today.  Thanks for the comments, guys.

Don

[George Des]

Slightly off topic but nonetheless another bearing lubrication question. I assume the bearings in the manual transmission are strictly splash lubricated by the transmission fluid. When doing a rebuild, should the all the bearings be soaked in automatic transmission fluid before installing?

George Des

[Atazman]

Hi George,

I'm not a mechanic, but seem to have gotten by without them............after asking for lots of advice.  Here's what I would do with manual transmission gears.  Anthing that meshes together... like gears on shafts,  like gears meshing together, like bearings on shafts ...... you should pour gear oil over them as you install.  After assembly, just pour gear oil over the gears and let it run down the teeth.    After filling with gear oil, try rotating the output shaft so that the oil in the gearbox is picked up by the gears and spread over them.  That's the best you can do.

Manual transmissions are lubricated by the gears picking up the oil and splashing it all over as you have already mentioned.