FJ 80 Front Axle questions

upcruiser

Perpetual Transient
I posted this on Mud too.

Well, after pulling my front axle apart I got to see exactly what was the cause of my ailments. First off, my rig is a '92 FJ80 with the stock gears, birfs, and inner axles.

Well, it looks like the passenger side inner seal failed causing the diff oil and grease to mix into a souply sludge like mixture. I'm figuring this happened on the last trip I took it on which was a 4,500miler with stops in different areas for some hard wheeling. Anyway, driver side birf had had a click to it for awhile that I never tended too, and on that trip, the passenger side did. A week after I got home, I was tooling up a local trail when I had something catastrophic happen in the front axle that made a hell of a lot of noise. Looks like from the mixing of the grease and oil, it end up causing my birf on the passenger side to run without grease, and the gears in the diff to be spinning in thick sludge, causing them to fail. And fail they did, as I discovered stripped splines on the inner axles along with chunks of metal in the pumpkin after draining it. Now, I've come to realize that I'll need to replace both birfs, all of the gaskets/seals, the inner axles, and the gears.

I thinking of going with Boby Long's super birfs and treated inner axles. From what I've read, they are stronger then OEM and cheaper to boot. My rig has a OME 2.5" heavy load lift and runs 33X12.50's. I use it for expedition type wheeling, but do get it into some heavy stuff frequently. Any reason why I wouldn't want to go with the Longfield's?

Next question, I want to retain the stock gear ratios as I feel they work well with my setup. Any recomendations for gears? OEM versus aftermarket? I typically go the OEM route whenever I can but my experience in the gear realm is a bit limited. Any insight you guys may be able to lend would be appreciated.
 

RAM5500 CAMPERTHING

OG Portal Member #183
Hey Kristian

No experience with the Longs!

Does your rig have the factory diff locks? If not and your looking for a unlocked stock 3rd i might be able to help.

I will be retrofitting an electric locker in the front of my rig soon and i will be replacing the entire 3rd member. I will be pulling a stock 3rd with the 4.10's and it has 132k on it and in great shape! I would give you a smoking deal on it.

I guess it also kind of depends on your time frame as well. I wont be ready for a few months. Probably too long.

Let me know.

Also, look into buying a complete third from the dealer (check with Cdan on Mud). I got one for $655 for my FJ60. Sounds high but if you cant install the gears yourself, you have to pay for setup and such and it gets up there fast. The dealer sells complete 3rds set up and ready to bolt in!
 

upcruiser

Perpetual Transient
Man, that would be a perfect setup if it wasn't for the time factor. I'm needing to get the rig up and running quickly if I take a new job that requires me to move, and give up my company truck/daily driver. I'll probaly have to contact Dan here. I would have thought that the full 3rd member would have been more then $655. And, I was happy and comfortable doing the axle work, up untill I found out I had gear issues. A complete 3rd member might keep me in the game....
 

Jonathan Hanson

Supporting Sponsor
Upcruiser;

The stock birfields on the 80 series trucks are significantly larger than those on 40s. With 33-inch tires I wouldn't worry about stock 80 birfields failing except in the circumstances you unfortunately met. However, if the Longfields are cheaper anyway . . . I've never heard a complaint about them.

Regarding the ring and pinion, I personally wouldn't trust an aftermarket gear set to be as durable as the factory unit (I've got 300,000 miles on my original FJ40 rear diff). I think a low-mileage used factory third member or complete axle assembly is the way to go.
 

RAM5500 CAMPERTHING

OG Portal Member #183
upcruiser said:
Man, that would be a perfect setup if it wasn't for the time factor. I'm needing to get the rig up and running quickly if I take a new job that requires me to move, and give up my company truck/daily driver. I'll probaly have to contact Dan here. I would have thought that the full 3rd member would have been more then $655. And, I was happy and comfortable doing the axle work, up untill I found out I had gear issues. A complete 3rd member might keep me in the game....

Yeah, sorry about the timing. I am still waiting for the locked front housing to arrive from CO

When you contact Dan tell him your a Mud member as well and he gives you the "Smart Shopper" price! It might even be cheaper then the price i mentioned, becasue i believe that was for an e-locker 3rd. I am not 100%.

Cool thing is that the 3rd is 100%, new gears, new bearings, etc.....

Used is always an option too! Let me know and i could probably find you one fairly quick!
 

Pskhaat

2005 Expedition Trophy Champion
There was an article a while ago somewhere about ``build it to break.'' Basically, if you put in stronger birfs, there are other things that may fail next like axle shafts or differentials, etc, whilst the birs were DESIGNED to only withstand a certain torque and should be the weak point. Anyway, unless you do some hardcore wheeling, might as well stick with used/new stock birfs.

As for the 3rd, I believe any year 80 91-97 will work on your 92, and it's probably cheaper to replace the whole 3rd member than get the parts & labor to repair (unfotunately). I'm pretty sure http://cruiserparts.net will have an unlocked 3rd for reasonable, and get it to you 2-3day ship. A locking stock 3rd will require grinding and change out of axle shafts.

After reinstall, change out your front diff 90wt at every engine oil change for a few changes to clear out all metalic crap.
 

ChuckB

Expedition Leader
Scott,

I think that article that you are referring to was in a past issue of TT a few months back. I remember exactly what you are talking about, unfortunately I can't look for it right now because all my old issues are at home...:mad:
 

Hltoppr

El Gringo Spectacular!
Second on using OEM parts, maybe a used 3rd member from cruiserparts and birfs from Dan...

Can't go wrong with OEM....

I'd call and have Dan run you a quote on everything you need, then depending upon budget and availability, check with cruiserparts too...then order what you need. I'd be prone to using new OEM birfs though...

-H-
 

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