Rear axle seal question.... (2 Viewers)

[80t0ylc]

Bumping this thread. I’ve been having a bunch of weird issues like my driveline running smooth on the highway one way and then grumbling on the way back after being parked, both with regular driveshaft and DC.

Also my rear locker dash indicator started flickering on and off and is now on full time.

Been meaning to change the diff oil as it’s been some time since last change. Finally did it and full of grease with pretty thick stuff on the diff plug.

Inner seals were last changed at regear so 10 years and 120K miles or so. Everything is much quieter and smoother.
So I’m not going to reinstall inner seals based on this thread since I really don’t need another maintenance item.

Question is if there’s any need to go nuts getting the grease out? First thing is whether or not the diff lock sensor issue is related, meaning it’s in a position to have a grease coat on it that’s causing malfunction?

Second is outside of cleaning the grease out of the bearings/outer axle that’s accessible, anything else to do beyond running a cycle or two of cheap oil to flush it?

I didn’t know this whole issue was a thing, not looking to OCD it, just basics on effort to get to “just gear oil”.

I recently regeared and rebuilt both axles. How much grease did you pack in bearings on last rebuild? Over packing might explain condition of diff fluid. In my research I decided not to add any more than what FSM instructed. As to leaving out the spindle end seals, consider this: Yes, most FF builds don't have these seals and rely on the diff oil to lube wheel bearings. Most are freight haulers or semi's of some sort that haul heavy loads. But these diffs are also not used in river crossings or experience extended off camber conditions that might starve upper side of lube. Most Toyota FF axles are designed for these other conditions that semi's do not normally see. There, I've said my piece.

 

[BILT4ME]

I recently regeared and rebuilt both axles. How much grease did you pack in bearings on last rebuild? Over packing might explain condition of diff fluid. In my research I decided not to add any more than what FSM instructed. As to leaving out the spindle end seals, consider this: Yes, most FF builds don't have these seals and rely on the diff oil to lube wheel bearings. Most are freight haulers or semi's of some sort that haul heavy loads. But these diffs are also not used in river crossings or experience extended off camber conditions that might starve upper side of lube. Most Toyota FF axles are designed for these other conditions that semi's do not normally see. There, I've said my piece.

3/4T and 1T GM pickups also have Full Float rear axles and they use nothing but gear oil in the hubs. The assembly consists of dipping each bearing in gear oil and installing the bearings and seals in the hub and adjusting the bearings. Then place the vehicle on a sidehill to allow the gear oil to run from the differential out to the wheels. Let it sit for 10-30 minutes with each side downhill. Then take it back to level ground and let it sit, then check levels and refill the differential.

I know this intimately because I failed to dip the bearings on my Dad's 78 K20 Chevy way back when and I succeeded in "welding" the bearings to the spindles.

I follow what Toyota did only because that's the way it states in the manual. Yes, I know for sure that others take out the inner seals and operate them that way. I know those will operate LOTS of miles and in all conditions that way as well.

 

[Tools R Us]

...
Also my rear locker dash indicator started flickering on and off and is now on full time. ...

Most often the switch or related connection/wiring. My first test would be to unplug the connection at the switch, if the light goes out and stays out, it's the switch, if it's still on, it's a wire problem.

... Question is if there’s any need to go nuts getting the grease out? ...

No, most will come out with the change, check in 1000mi or so, if thicker than preferred, change again.

 

[Tools R Us]

Do whatever you prefer, no need to reach for excuses to justify. The Toyota says one is likely good enough for most?

... As to leaving out the spindle end seals, consider this: Yes, most FF builds don't have these seals and rely on the diff oil to lube wheel bearings. Most are freight haulers or semi's of some sort that haul heavy loads.

Most all full float axles are used for heavy duty, some on semis, but also common on lighter rigs.

...But these diffs are also not used in river crossings or experience extended off camber conditions that might starve upper side of lube. Most Toyota FF axles are designed for these other conditions that semi's do not normally see. There, I've said my piece.

No idea what water fording has to do with it, you are saying only Toyota rigs do that? If anything oil bath has the advantage of water intrusion being easier to detect and rectify, simply change the oil.

Due to the spindle/hub design, it's impossible to starve the bearings in off camber situations, even with the rig on it's side, the bearings would still have oil. If anything occasional off camber is a good thing, flushes the oil in the hubs.

 

[Nay]

Most often the switch or related connection/wiring. My first test would be to unplug the connection at the switch, if the light goes out and stays out, it's the switch, if it's still on, it's a wire problem.



No, most will come out with the change, check in 1000mi or so, if thicker than preferred, change again.

Thanks for the locker info - so the indicator is based on the switch, not at the axle. What’s funny is I swapped shocks for maintenance and it went out, came back with the other shocks and then stayed on permanently after a bit of additional lift. That sounds like wiring or zombies.

As for the seals, It has occurred to me to not do anything right now since my outer seals aren’t leaking. I’m thinking I’m gaining nothing with a PM of the outer seals and I just keep an eye on diff fill levels with a finger test for viscosity, although not sure what I “prefer” except it’s quiet. Do I need to pull them if I don’t intend to replace them?

A lot of grease came out with the change - a classic birf soup sans birfs.

 

[Nay]

I recently regeared and rebuilt both axles. How much grease did you pack in bearings on last rebuild? Over packing might explain condition of diff fluid. In my research I decided not to add any more than what FSM instructed. As to leaving out the spindle end seals, consider this: Yes, most FF builds don't have these seals and rely on the diff oil to lube wheel bearings. Most are freight haulers or semi's of some sort that haul heavy loads. But these diffs are also not used in river crossings or experience extended off camber conditions that might starve upper side of lube. Most Toyota FF axles are designed for these other conditions that semi's do not normally see. There, I've said my piece.

It was 10 years ago and I had the job done by a master Lexus tech. Last time I changed the gear oil it might had well have been new, but it’s been a long time. Obviously just an inner seal failure same as the front axles.

I don’t mind the work and it’s not a big deal to PM this stuff, but I’m also pretty big on “why bother” especially since the inner seal failure will begin to starve the diff of proper fluid levels.

All things being equal, protecting everything in the diff is a higher priority than the outer axle components and it sounds like we haven’t found a single person reporting they had an issue with deleting those seals.

Understand why people would feel otherwise, of course.

 

[80t0ylc]

Do whatever you prefer, no need to reach for excuses to justify. The Toyota says one is likely good enough for most? ......

You know what would make sense, is that this - leaving the seals out or removing them - was shown in the FAQ rear axle maintenance threads. Because this is not mentioned AT ALL in either FAQ thread (3 are listed, but 2 of them are the same thread). I did some serious research before tackling both front and rear axles and I have to say that, after the fact, the axle FAQ threads leave a lot to be desired. I mean leaving this axle seal out is a serious deviation from the FSM. Not that the FSM has all the details or answers, but I thought the FAQ threads were intended to guide the inexperienced to supplement the FSM info.

..........No idea what water fording has to do with it, you are saying only Toyota rigs do that? If anything oil bath has the advantage of water intrusion being easier to detect and rectify, simply change the oil.......

I'm not saying "only Toyota", I was refering to previous posts by you and others to the effect that "Toyota does it this way". I don't claim to know why Toyota designed the 80's FF axle the way they did, but it makes sense to me that although gear oil is superior to lubing bearings, that grease is superior in staying in place during water intrusion or put differently, is not washed out as easily as gear oil. Now, I'm talking extended submersion, such as in flood or swamp conditions.

.........Due to the spindle/hub design, it's impossible to starve the bearings in off camber situations, even with the rig on it's side, the bearings would still have oil........

Is this your opinion or how did you reach this conclusion? I can see how the wheel bearing cavity would retain some gear oil before losing the supply from the diff due to the off camber condition. But, it would not be replenshed or cooled and could even loose oil that would be splashed out during the revolution of the axle.

 

[Tools R Us]

Don't do it, would be far too stressful!

... I mean leaving this axle seal out is a serious deviation from the FSM. ...

I have likely read entire FSMs and have never seen anything about adding aftermarket lockers, longer springs, shocks, bigger tires, etc. You wouldn't dare to do any of that silly stuff,,, right, none of it is condoned by Toyota?

... grease is superior in staying in place during water intrusion or put differently, is not washed out as easily as gear oil. Now, I'm talking extended submersion, such as in flood or swamp conditions. ...

Grease does a poor job when mixed with water, bearings, etc, rust, fail. I strongly recommend against parking in swamps.

... Is this your opinion or how did you reach this conclusion? I can see how the wheel bearing cavity would retain some gear oil before losing the supply from the diff due to the off camber condition. But, it would not be replenshed or cooled and could even loose oil that would be splashed out during the revolution of the axle.

I didn't come up with anything, what we are talking about has been common, successful practice for what, over half a century. Maybe you can explain a plausible/logical way that the oil could jump out of the hub? Agree, if you drove the rig on it's side for say, 10k miles, would want to change the oil trapped in the hub, but there maybe other, more pressing issues?

 

[80t0ylc]

........

I have likely read entire FSMs and have never seen anything about adding aftermarket lockers, longer springs, shocks, bigger tires, etc. You wouldn't dare to do any of that silly stuff,,, right, none of it is condoned by Toyota?.....

Touche

.........Grease does a poor job when mixed with water, bearings, etc, rust, fail......

Gear oil has the same problem. I use a high quality synthetic grease, not what's on sale this week. I know it still suffers with water intrusion, and the front wheel bearings & birfs are also exposed to the same problems since they're grease lubed.

......I didn't come up with anything, what we are talking about has been common, successful practice for what, over half a century. Maybe you can explain a plausible/logical way that the oil could jump out of the hub? Agree, if you drove the rig on it's side for say, 10k miles, would want to change the oil trapped in the hub, but there maybe other, more pressing issues?

Maybe so on the practice. No explanation needed - if oil is not sealed into the hub, bearing action could propel it out gradually or at least reduce it to a minimum level, if not replenished. Also important, if it's not being replenished, it's not being cooled. It doesn't take much off camber slope to keep oil supply from reaching the end of an axle tube. Not a big problem in most cases for recreational wheeling, but for overlanding where vehicle could be carrying close to its weight limit and/or towing for extended distances in the outback, could become a concern.

And I guess, that's my point. Extreme environment situations - I'd like to think my 80 is up to the challenges of extended overlanding, not just recreational off roading or DD use.

 

[Nay]

^^^this is really a question of what kind of maintenance you prefer.

My personal view is that there is a Toyota obsession with packing bearings. It’s like something that has to be done and nobody knows why.

I have never done an interval bearing grease packing PM job and have also never torn into my front end for a rebuild and found grease lacking anywhere, including the diff because the inner seals don’t last.

Losing that problem where possible frankly sounds ideal, because I don’t have any interest in packing bearings with grease as fun as it is to do. I suspect that’s pretty common since we often find these areas get neglected in maintenance and are only addressed if there is a leak somewhere.

 

[80t0ylc]

^^^this is really a question of what kind of maintenance you prefer.

My personal view is that there is a Toyota obsession with packing bearings. It’s like something that has to be done and nobody knows why.

I have never done an interval bearing grease packing PM job and have also never torn into my front end for a rebuild and found grease lacking anywhere, including the diff because the inner seals don’t last.

Losing that problem where possible frankly sounds ideal, because I don’t have any interest in packing bearings with grease as fun as it is to do. I suspect that’s pretty common since we often find these areas get neglected in maintenance and are only addressed if there is a leak somewhere.

Yeah, I have to agree. After a lot of thought and research, I like the idea of reduced maintenance and your decision to leave the seals out makes more sense since gear oil actually lubes better than grease. The flange gasket is going to be the seal now on that side of the bearings. Plus it would probably be a good idea to regularly check the level of the rear diff. I'd also make sure the vent is clear with finding the grease in your diff fluid. When I rebuilt my axles, I removed the vent fittings on the axle housings and was surprised on the front one. It had a thin layer of grease that completly covered the hole in the housing. It was easy to see & remove with an empty housing. Rest of the vent hose was open, but had I not seen that at the housing I'd still have a blocked vent. The rear housing vent hole was not plugged, but the old diff fluid didn't have the grease you found.

 

[Nay]

Good point on the vent, hadn’t thought of that but definitely a spot to ensure isn’t blocked.

I had already ordered the flange seals and gaskets so I think I’ll get in there and clean it up some.

 

[artech]

Was searching and found this thread because I am going to be tearing into my rear axle right off. No leaks or noise at 248,000mi, but rust has pretty much destroyed my brake plates and I need to replace them. (censord:'n rust!) So while it is all apart I'm putting new bearings in the rear because why not really. It'll already be all apart. And after reading this thread I am pretty sure I will be deleting the inner axle seals on my rig when I do it and running the bearings in the gear oil. So here's my question- what is the new fluid capacity of the rear axle with the seals removed? How much gear oil will I need to get?

 

[Tools R Us]

... So here's my question- what is the new fluid capacity of the rear axle with the seals removed? How much gear oil will I need to get?

Not really a significant difference, maybe a couple of ounces.

 

[KiwiDingo]

Great read, never even considered leaving our the seal and running on oil alone. I did this with my trailer bearings converting from grease to oil and haven't looked back.

 

[artech]

Not really a significant difference, maybe a couple of ounces.

Just fill to the bottom of the fill port like usual then?

 

[Tools R Us]

Just fill to the bottom of the fill port like usual then?

Yep.

 

[BILT4ME]

Just fill to the bottom of the fill port like usual then?

Just make sure you pack the bearings with regular wheel bearing grease or tip the truck hard left and right for 10 minutes per side to get oil into the bearings then top off the oil. Otherwise you won't make it a full mile from the house.

I know from experience.......the hard way.

 

[artech]

And does running them in oil make any difference to the torque on the bearing preload? What do I set the lock nut at?

 

[Pascoscout]

Just make sure you pack the bearings with regular wheel bearing grease or tip the truck hard left and right for 10 minutes per side to get oil into the bearings then top off the oil. Otherwise you won't make it a full mile from the house.

I know from experience.......the hard way.

I was thinking about using an engine assembly lube. Would provide the lubrication for initial use but it's designed to fully dissolve in the oil once everything gets where it needs to be. Regular wheel bearing grease usually turns to sludge when mixed with oil. Thoughts?