View Full Version : ARB issue?

09-27-2005, 02:21 PM
A while back my rear ARB, originally installed in the third oh, around 1997 or so, would spit some gear oil out the solenoid when released. Seems to have settled down some lately.

Then, the other day I was driving down the road and heard a kinda 'bang' sound in the driveline, had to be rear, but I felt nothing at all. Nothing revealed in visual inspection.

A J**p friend (yes, I have those) immediately suspected the ARB. Said the early ones would start engaging themselves from time to time - with grenading not far behind. Darn, that could get real inconvenient.

TR Burris at ARB never heard of such a thing. David Fritzche on 4x4wire.com had a cross pin grenade in his, on the 'Con. Ate his ring & pinion.

I know ARB changed the piston design, and if I weren't lazy I would have installed the new one that ARB sent me, and maybe that would take care of the gear oil spit AND the autolocking 'feature'. Or would it? Anybody ever hear of or experience such a thing? Wouldn't the springs be suspect in such a case?

Could get REAL inconvenient in November, in hunt season, at -20F, in the snow, at 10K feet.

09-27-2005, 03:38 PM
I've never heard of them "self engaging" but I'm no expert. Since they are sprung open and air closed, I would think most of the individual springs would have to fail for it to lock without air. Is your air source unpressurized most of the time? My electric compressor is off until needed. If you have a storage tank that is charged all the time, maybe the valve is leaking and pressurizing the locker? You don't have an inspection cover on the diff do you? It would be good to know that the cross pin retaining bolt is intact.

09-27-2005, 08:44 PM
When I was gunning E-Hill at moab some years back, a guy had the retaining pin in his cross shaft break, allowing the cross shaft (pinion shaft in Toyota vernacular) come loose in his front ARB'd diff, effectively "locking" his front axles from turning. The cross shaft then opened up a nice air conditioning vent in the front of his diff housing. Fortunately this was at the start of the trail, he and his wife parked and rode with others.

Just sharing a failure mode I have seen first hand. No idea if it's the related to your issue. I have pulled several cruiser 3rds which had a broken, but still functioning cross shaft retaining pin. I know that mini/runner 3rds use a drive pin for this and cruisers use a threaded fastener, but it still might be something to look into.

I know it's major PITA, but pulling the 3rd and doing a visual inspection would seem in order. If you have a spare 3rd, maybe swapping it in to get around to the ARB might be a little less work...nah. But like you wrote, having it grenade would be worse.

09-29-2005, 08:35 AM
YEah, I guess I gotta pull the third - BEFORE hunting season!

One thing makes me think my J**p friend is right- when I was backing out of the Goodyear shop, I was turning and I heard a quiet squeal, just like you would hear if you wuz locked on polished concrete and chirping a tire oh so gently. Then I pulled forward, and nuttin' funny happened.

So it's time to tear apart the ol' ARB. Glad I got some edjycashun on R&Ps here a while back thanks to Chief. Justin's rear third is still running strong.

09-29-2005, 11:14 AM
The one thing I have noticed with ARB's phone sales staff is they know nothing or at least that is the training. to get the real answer you have to get to a tech and then you may not get the staight skinny. number 1 problem is always the installer, every time I have been to a demostration the installer is to blame. But on the info board and some of the chat list, ARB has had many problems, from the ring mount flange not being true to stuff braking. It is a great product, but has some problems as with anything mass produced. I am glad to see you are taking it out to see route, intead of waiting for it to blow up. later robbie

09-30-2005, 09:55 AM
Hmm. I have an ARB diff apart tonight and tonight only if you want to compare stuff on it. The only ARB failure I've seen is a blown up (destroyed housing) and ones that the little torx head screws have loosened up on or broken off on.

Good job on Justin's diff. I just took apart the 4.88 I slapped together for the front of my rig for cruise moab (and broke in on the hole-in-the-rock trail.) The gears (even though they were last minute, cheapo 4 cyl genuines) looked great. They are still not broken in, but were (are?) getting there. I didn't put a lot of miles on my front diff. The pattern still looked great.

PS "nominal" checking distance on a toyota diff is tough to figure out because of variation in pinion head thickness from different vendors. If all you ever put in were "toyota" gears, then this would be good to know. The yukons I'm putting together now show the CD in inches on the pinion head. no +- from nominal is given. I may have been trying to learn something that isn't important for setting up aftermarket gears.

Tonight I finish the 5.29s on the V6 ARB. Right now the pattern is too close to the toe and 'flat.' I need less pinion shim. I'm guessing I'll end up with .067 or so under the head (v6 gears on v6 diff).

10-03-2005, 08:06 AM
Your CD experiences with aftermarket gears matches mine. Actually, the Toy housing specs are so consistent that the prior pinion shim makes a very good starting point.

So, I took apart my ARB, and what did I find?
Pick one:
a) The thing grenaded, holding on only by a spit and a prayer.
b) It was jammed with crud due to the typical lack of maintenance of Red Chili.
c) There was a dead mouse in it, and as the corpse expanded it locked the diff.
d) Not a dang thing. It was a thing of beauty and a joy to behold.

If you picked d), "we have a winner". I changed the piston to upgrade to the new design, took everything apart and cleaned it up, and installed the new return springs that TR Burris sent me, just cuz. Oh, two other things: the backlash was .010", a couple thou more than I like, so that was good to fix. Also, the hard air line was brushing against the ring gear, a likely failure sometime in the next year or two (I did say 'lightly').

So what made the 'bang'? Well, when moving the truck out of the garage last night, much to my surprise I could not MOVE the ebrake lever. Turns out then dang cable is melting, in close proximity to the new 3.4 headpipe. Somewhat of a heat management issue methinks, hafta contact Mike Caskey on that little detail. When I finally forced it to set the brake, then release, it didn't. So I banged on the lever under the truck with a rubber hammer until it released, then realized: it probably hung up that day when it banged, and as the cable warmed up, it finally released fully, banging against the stop. *Maybe*, mystery solved.

10-03-2005, 09:56 AM
Bill: Lots-o-work, eh? Well, I rebuilt my diff 2x this weekend. Arg. I know the out/in/out/in routine pretty well.

Lack of redchilli II maintenance..yeah right. I was even going to add a little thing on the end of my turbine whine/whistle post that says, "except Bill, whom I KNOW would take it all apart again and start over, this time following the FSM to the letter, then re-fill untested diff with high buck synthetic red line 85/140 gear oil." :)

Anyway, bang or no bang it sounds like it was a worthy trip into the smelly diff. :)

The pinion is currently at .063 and COULD MAYBE go to .065 for that competion pattern look, but I was pretty close at .065

Some things I need to record for other setting up their own gears will be on another post.

10-03-2005, 01:00 PM
Your diff is smelly?


You sure it ain't the arm position as you're maneuvering the chunk into place?

Oh, and I DID use some Redline Shockproof (80/90, not 140/whatever. Sheesh:p ) I had laying around. Gave the Valvoline to a friend last night.

10-03-2005, 03:52 PM
Yeah, I don't like the smell of gear oil.
I think it is the high sulfer content in it that makes it stink.
The synthetic stinks less and
redline stinks the least.

The BG additive stinks like old gear oil. (You know, the slightly rancid smell you get when you take out the carrier cap bolts or stock ring gear bolts?)

I was, like you, feeling pretty weak hefting the diff back up there again. I swear the V6 diffs weigh 20 pounds more than the 4cyl diffs! And you have to be so carful of that copper arb line on the side that seems to be magnetically attracted to the axle housing. (Mine has some dings to be sure, but it doesn't leak (yet).).