Found gear teeth during front diff fluid change (1 Viewer)

[ikellymo]

Hi All, I've searched the forums and found lots about what to do once you've blown the front diff. I am hoping that's not the case. I bought my LX470 at ~200k, I'm at 230k and currently going through the PM's found here: 200k Service & PM - Suggestions? (Thanks a ton).

I decided to save the ~$150 per gearbox my oil changer wants, and do the diffs + TC myself. When I pulled the drain plug I found a mess of metal chunks ... exactly what you DON'T want to find. I've definitely put her through a few torture tests on rocks but its been at-least 5k since and I haven't noticed any issues except increasingly extremely poor fuel economy (11.3MPG avg).

So I'm asking - is there any chance everything is OK? am I just lucky as hell? Do I need to replace the diff immediately? Is it worth pulling the cover and inspecting further or do I just need to get this rebuilt?

I'm in the bay area and have a good toyota mechanic but haven't found a landcruiser expert yet.

Thanks!

 

[cumminsBase]

I would definitely pull the cover and inspect further.
If it was me, I would rebuild the differential.
Yet first things first... pull the cover and take a look.

 

[45Kevin]

Well, no problems to date so it's probably not in imminent threat of grenading during normal daily use.
But, there is definitely some missing, or partially missing teeth on your gears so it should be addressed before you plan to test in the field again.

 

[ikellymo]

Thanks for the really quick responses. I guess to be more specific, what should I look for if I pull it apart? For example, 1 broken tooth is fine, where 4 are not? I'm not sure I could assess how bad it is.

 

[cumminsBase]

No broken teeth are fine.
One broken is bad.

Sorry mate, it is what it is.
No way to sugar coat it.

Those are not shavings... they are CHUNKS OF METAL.

 

[nukegoat]

She's dead Jim

 

[gatormark91]

Drive it until it dies. If you are worried, buy a junkyard one and keep it on the side until the one in the truck finally munches itself. My front diff has a sliver missing from one of the teeth, I wheel it and don't think about it. When it goes, I'll yank it.

 

[4Beast]

I can't imagine it ending well if there are any more of those chunks floating around and they end up in the gears. As they say down south, she gone.

 

[hankinid]

It's toasted very well.

I can recommend A+ Japanese Auto Repair . They're in San Carlos...101S to Holly, left on Industrial, and they'll be on your right in a mile or so. They know what they're doing, and you'll find a cruiser-head or 2 in there. Feel free to tell them that Steve in Idaho referred you. Good luck & please report back.

 

[DTCsk8er]

Bad news is its probably done. You can inspect everything with the diff pulled, but there are probably small shavings that damaged the bearings as well. New gears and a master kit in your future.

Also, the front diff is special, and you can't just pop off the cover that easy. I'd remove the driveshaft and hub gears, get some duct tape to cover s*** up, and drive it around until I had time to remove the diff entirely.

 

[Somebodyelse5]

Well, no problems to date so it's probably not in imminent threat of grenading during normal daily use.
But, there is definitely some missing, or partially missing teeth on your gears so it should be addressed before you plan to test in the field again.

With that one tooth missing, the adjacent teeth are now seeing more load and their failure should be expected very very soon.

It's time to swap the gears, if it were me I would do a front locker while I was in there. I would strongly discourage "driving till it dies" in this scenario, some nasty carnage can be done to the housing if a shed gear tooth finds it's way into the mesh...

 

[suprarx7nut]

Are those striations definitely indicative of a tooth from a diff? That doesn't look the way I expected.

Any chance those pieces of metal are anything other than ring gear teeth?

 

[ikellymo]

Thanks all!

@DTCsk8er, do you mean also disconnect the drive axles to the wheels so they rotate freely? I will have to look into that.

@Somebodyelse5, I'm definitely going to do front locker if it gets rebuilt. I run 285/65R18 (32.5in) KO2s and am happy . With a current gearing of 4.1, I'd probably only go to 4.3 if I change, because decent fuel efficiency is important to me for the amount of highway driving done. More research to do though... Some people say efficiency goes up and some say it goes down with higher ratios.

@suprarx7nut, I don't know. This is the first time *I've* cracked the seal on that diff. The LX was new to me at ~200k. I don't have enough experience with diffs to offer much help. There are definitely tooling marks visible.

 

[Somebodyelse5]

Thanks all!

@DTCsk8er, do you mean also disconnect the drive axles to the wheels so they rotate freely? I will have to look into that.

@Somebodyelse5, I'm definitely going to do front locker if it gets rebuilt. I run 285/65R18 (32.5in) KO2s and am happy . With a current gearing of 4.1, I'd probably only go to 4.3 if I change, because decent fuel efficiency is important to me for the amount of highway driving done. More research to do though... Some people say efficiency goes up and some say it goes down with higher ratios.

@suprarx7nut, I don't know. This is the first time *I've* cracked the seal on that diff. The LX was new to me at ~200k. I don't have enough experience with diffs to offer much help. There are definitely tooling marks visible.

Please send pictures of what you find. Very curious.

I think if you swap the ratio of the front diff, you'll need to swap the rear diff also

 

[I Lean]

There is a chance it's teeth from your spider gears, but I think it's more likely R&P. Either way it needs to be addressed, as has been mentioned.

 

[jrmudder92]

So I had the same problem. But what I’m confused about is how this makes no noise. You would think it would bind or something. I also bit the bullet and did front and rear arbs

 

[ih8everything]

I would pull the front diff, CVs, and driveshaft; lock the center diff so you can still drive around in RWD, and then drive the front diff over to a shop.

Try Valley Hybrids in Stockton. They did my locker installs and were great to work with.
There's also Mudrak in Sonoma. I haven't used them for any mechanical work, but I did buy my RTT from them. Service was great and I've only ever heard great things.

Both are great cruiser specialty shops. Good luck!

 

[geanes]

Can't run mismatched gears front and rear. If you re-gear the front, you HAVE to re-gear the rear with the same ratio as well unless you want to do something absurd like run 37s on the rear and 33s on the front and make your 100 into a sandrail.

Sorry to say it, but your front diff is done IMO. Once things start sloughing off, the integrity of the system is in doubt. Stress risers can occur and catastrophic failure can occur which can do way more damage to other bits. I'd either bite the BIG bullet and regear front and rear with lockers, put in new front gears (same ratio) with a locker, or just new front gears (same ratio). Depends on your budget. For me, I'm saving my pennies for the day my front diff breaks (98 LX with 2 pinion) with the plan to put lockers front and rear and new gears.

 

[ikellymo]

Thanks all. I would either stick with 4.11 or go up to 4.3 on both F and R, not attempt mismatched. I pulled the front diff this weekend and took a look at the ring gear. This makes sense why it still works without feeling anything. The whole diff is shipped off to Zuk for a rebuild and locker install. I'll wait for him to pull it apart to see if anything happened to the pinion. I'm also pretty curious what the backlash currently is and forgot to measure it.