I plan on doing the diff breather mod using a piece of tubing so that there's NEVER a pressure buildup ever again.

Instead of JB Weld to seal the pinholes, am I better off simply using primer on the housing and then spraying a coat of bedliner on it? Will either hold up better than the other? My concern with the JB Weld is that if the expansion rate of the JB Weld doesn't match that of the housing, one of them will fracture/crack as the housing heats up and cools, and I'll have another huge repair.

And, if I do put a coat of JB Weld on the whole back area of the housing, how thick a coating is best? Should it be almost a film, i.e. just to seal up all the pinholes? Or maybe about 1/16" thick coating? Maybe thicker, like 1/8"? Or just smear it on with a gloved finger simply to smooth the surface and fill the pinholes?

Thank you for any help or advice you can provide!

 

I'm confused. Is there something wrong with your housing? What are you trying to accomplish with the jb or bedliner?

If you're just trying to make it pretty. The only way you'll get it clean is to remove the housing from the vehicle, sandblast it, then paint it. If you plan on doing this over top of rust you're wasting your time.

If your trying to get protection for your ring gear you need weld on armour like this : http://www.frontier4x4.com/Trail-Gea...ialArmor-Large

 

How many pinholes are we talking here? I brazed my rear diff, zero issues a year plus later. I had a thin spot, made a patch, and brazed it all the way around.

Just say no to the bed liner idea.

 

yeah, i'm confused as well with the "pinholes". i'm also assuming it's chips/rust spots in the paint on the diff/axle - if so the only real fix is to strip it down and repaint.

extended diff breather is a smart move though. i extended mine up to the top of the bed-rail behind the tail lights, highly unlikely that i'll get water up that high.

 

My housing is rusted to the point where the diff fluid was leaching through the metal. About a year ago it got low enough to (I believe) fry the pinion seal and possibly a pinion bearing or more. My initial intent was to replace the entire rear end but that was a nightmare so I bought a replacement diff a week or so ago.

I'm replacing the bad diff and cleaning up the housing as best I can to remove the rust and hopefully prevent the leaking from happening again. I'm doing the breather mod too to ensure that there's no pressure buildup from breather-clog. I'm also replacing the axle inner seals as there was gear oil on the ABS ring on both sides, but not in the brakes.

If you want the full story, my first or second post explains in detail what happened.

What I'm trying to accomplish with the bedliner or JB Weld is to seal up the porous metal and coat it so that the oil can't be forced through the metal because of pressure buildup. I figure that if there's an open airway through the breather mod then there'll be no cause for the oil to be forced through the housing.

Regarding what it looks like, I don't care, as I'm simply trying to get a moving vehicle. It's been out of service for nearly a year while I looked for a replacement diff and/or rear end (to which I got F'd by a yard in NY when they sold me a rear end with the wrong gear ratio. Grumble, long story, I won't go there. But I'd avoid Chase credit cards and the Saw Mill Auto Wreckers in Yonkers NY.

So if you know the best way to clean up and seal the rusted housing, please let me know! I'm trying to finish this up within the next day or so so that I don't have to rent a car in about a week for my parents' doctors appointments.

 

Re the pinholes:
The rust was flaking off in pieces thicker than a quarter.... several layers worth of 'quarters' in fact. I broke them all off an then used a wire brush attachment on my drill to get down to bare metal. Tapping it with a hammer caused much of the looser rust to fall right off in chunks.

Prior to that, the back of the diff was always saturated in oil with no obvious origin. I believe it was simply leaching through the metal itself, as I've read about that condition for these rear diffs. It got so bad that it would drip after driving, and I'd have to add diff fluid every couple of months to top it off. It finally went about a year ago when it apparently ran nearly dry when I was on the highway.

The housing metal, unfortunately, is very pitted, and even after having drained the diff a couple of weeks ago, there was still oil weeping from the metal. This tells me that it's porous, because when I'd wipe it down it would weep a little more. I was using the term pinholes because a previous poster with the same problem fixed his by using JB Weld and said it has lasted and that was several years ago.

My goal is to get the truck up and running again and probably sell it within a year or two. So I need a repair that will last on the order of a few years or more.

 

in this case, the only legit fix is to outright replace the rear axle if the pitting is going through the housing. considering a used axle averages only $100-200 on CL or junk yard, I personally wouldn't even waste my time/energy on trying to repair and most likely have the repair fail sometime down the road (and usually at the least opportune time). since the axle is leaking oil, it will be very hard to get any epoxy to form a proper bond on that surface unless you removed it from the truck, drained it, sand blasted, then wiped down with a solvent to cut through the oil.

since you mentioned selling in the near future - if i was a buyer this repair would send up red flags and i'd seriously be lowballing the price because of it. plus, don't you guys have inspections on the East Coast? I'd think it wouldn't pass inspection?

 

The rear end has already been removed from the truck. I've been looking for a replacement now for 11 months. Yes, 11 months. Unfortunately I don't have the $2600 - $3000+ that various repair shops quoted me on replacing with new Toyota parts.

I don't even have the $1250+ for used ones from yards. I would have a significant amount of difficulty coming up with $750 for a used 1998 4Runner here in MA that appeared in good shape but had nothing but grime where the diff breather was supposed to be, which leads me to believe that the breather rusted off years ago and oil was spewed from the hole for who knows how long. I couldn't even feel the hole for the breather. So I ended up buying a used diff for $350 that at least is the correct gear ratio.

Regarding selling it, I have no objection to selling the vehicle with the price of a $800 rear end replacement built in, and I'd inform the buyer about the repair anyway, as I'd want to know if I were the buyer. Besides, the lemon laws in MA are very harsh.

We have inspections here but rear differentials are not on the list, so unless oil was pouring out of it I believe it would be ignored.

I've already had the major issues repaired -- strawberry milkshake, radiator replacement, fuel line replaced, etc. I simply want a running vehicle again... in 3 weeks it will be a year since it came off the road.

 

who ever sold you that diff really porked you at $350, I sent a front and rear diff from an older 4runner to the scrap pile at a junk yard because they said they weren't worth anything anymore

 

If you want to permanently fix it, you have to either replace the housing, or weld on a new diff cover. I see that you are in Mass too, I work in Attleboro. When I was looking for a new housing, I found that all the 4runners in MA salvage yards were rusty, though they may not be as rusty as yours. Anyway, I got lucky and got one from a guy in FL over on T4R.org and he helped me get cheap shipping up here. For you, I'd call every salvage yard in the region and if they have ANY 3rd gen 4runners, go look at it and see how rusty the housing is.

If you want to temporarily fix it just to get you through a year or so, you can strip the metal bare, fill it with something to find all the pinholes, and use JB weld on it. It won't last forever but mine was still going strong after about 8 months, other guys have gone a year or more before it leaked again.

 

I'm not sure how to respond, warpigg. If you check the prices on car-part.com for a carrier (i.e. differential) for the rear, 4.30 gear ratio with diff lock, you'll see prices ranging from $275 to $1200, with 90% of them between $300 and $550. That doesn't include shipping, btw, from as far away as AL or CA to MA. I drove 45 minutes to get it, which beats the hell out of driving to NY, VA, PA or further, or paying $100+ shipping, which were the quotes I was getting.

If the part works, $350 works for me, as it's on the lower end of the range I just mentioned. I've been without a truck now for nearly 1 year trying to find anything from a low-priced entire rear end for $750 or less (including shipping, because if they're going to charge $250 for shipping I may as well get it closer to home for $1000) all the way to just the diff, which I finally found in my home state. Plus *I* have to pay for return shipping if it doesn't work or I don't like it, etc., as most yards won't eat the shipping either one or both ways.

You didn't say how old your 'older' 4Runner was but for reference mine is a 2000.

From what I can tell, I think you're the one that got hosed by giving away a front and rear differential that the yard probably sold for at least $400 combined between the two, possibly another hundred more, I have no idea. Of course they're going to tell you they're worthless; they want you to give it to them for free so that they can sell them.

Thanks for the input.

 

Thanks for responding to this post, Nelson, as well as my previous posts.

I'm also finding that all of the housings up here and in New England are in generally bad shape, and even if not quite as bad as mine, it's still not worth the $800+ most of them want for a rotting rear end.

I had limited success getting one from NY; it was in terrific shape and only $450. Unfortunately it was the wrong gear ratio (even after multiple confirmations on their end) and I had to return it. I couldn't check the ratio there myself when I bought it because the backing plates were semi-crushed against the drums. I didn't find out until after getting it home and getting it freed up to do the spin test.

I've called places all over the country over the last 11 months with limited results: some want too much for a piece of crap, or sometimes the shipping cost is too high for freight from CA to MA. Others insisted that I arrange to have it picked up or shipped myself from other parts of the country and again, shipping charges of $200-250 leaves very little room for an affordable price, at least for me.

Regarding the application of JB Weld on the housing, how thick did you apply it? Film coating just barely covering the surface? Thicker? After the 8 months, did you finally replace the entire read end on your own truck or just the housing? And did you put primer and paint on the JB Weld or leave it as is?

 

not all diffs have rear e lockers that's why it was so expensive and the diffs im talking about are from a 86 4runner even the ones that were in my 97 4runner weren't worth more then $100 a piece used. if you want to fix it on the cheap get an axle with diff out of a 4runner without a rear locker. do you even use the rear locker enough to want to keep it

 

Yes, I agree that's why it was so expensive, because it has the elocker on it. And no, I don't use it, and probably never will. But my attempt at replacing the ENTIRE rear end in excellent condition with a non-locker for $450 was a failure because even though it was it great shape it was the wrong gear ratio.

Not only that, but after removing the axles and inspecting them, both brake drums were coated with gear oil, telling me that the axles were blown. I was going to use my own axles anyway so it wasn't relevant, but again it was the wrong gear ratio anyway so wasn't a solution.

After nearly a year of trying to get anything at all that works, I finally found the diff that I bought, less than an hour away, and the correct gear ratio. I'm further along in this repair than I've ever been. I'm simply hoping that there's nothing wrong with the differential, as they only gave me a 30 day warranty on it, which leaves me about 20 more days.

EDIT:
This was supposed to read "But my attempt at replacing the ENTIRE rear end WITH ANOTHER ONE in excellent condition with a non-locker for $450...."

 

shouldn't matter if the gear ratio is different in a replacement complete axle - just swap in your good diff that matches the front. i don't understand the prices you're experiencing on the east coast, out here in CA a complete axle housing is only like $300 from a wrecking yard and we don't have rust issues. if it has an e-locker then the price jumps because they are made of gold or some BS like that. an e-locker can definitely be put into a non-locked housing and vice versa.

with the prices you're spewing out, it'd be cheaper to just buy a brand new Trail Gear housing and have them ship it to your door. housing is less than $500 and I think shipping is around $100 or maybe less.

if trying to repair your rear end with a temporary patch, you may want to try a product called PC-7. I use it all the time and like it better than JB Weld. Only store i've seen it on the shelf is Ace Hardware or online. It is more of a paste epoxy that cures rock hard, basically the same properties of JB Weld - but I think you'll have an easier time with it especially if trying to spread it out, still difficult though. Good luck!

 

I don't understand what you're saying about mismatched diffs, but the front and rear are both 4.30, and have to match, that I know.

The prices for axle housings with the carrier and both axles average around $750-900, so if I have to buy one from anywhere that I can't drive a couple of hours to get, it will cost me about $200-$250 shipping, by freight. That puts it out of my budget, as I'm between jobs and barely making ends meet. If you're talking about a bare housing for a 4.30 with an elocker, they're up around $250-350, and that's not even necessarily in good shape. That's why I'm opting to patch mine up temporarily until I either 1) get a job and can get a good replacement housing, or 2) get a job and with luck buy something better on gas and sell the truck within a year or two.

I don't doubt that CA has good prices. I've called some of the CA yards but they either won't ship at all or charge too much for shipping, making it too expensive to buy.

I believe you're wrong about mixing an elocker with a non-elocker housing/diff combo and vice versa. If you check some of the other threads on this site you'll see that there are people that have made mods to their housing to accommodate an elocker diff. In any event, I would have been more than happy with a non-locking 4.30 with ABS rear end, but again, the 4.30's are virtually impossible to find, or too far away, or in worse shape than what I've got. Also, it's not just the housing I need, I need the diff too because mine has a bad pinion seal and possibly other damaged components that I haven't identified yet. I was very surprised to not find at least one broken tooth because of all the noise that was coming from the diff when it grenaded on the highway last year. When I get my axles back in using the replacement diff I guess I'll find out if I may also have a blown axle bearing; I'm praying I don't and there's no evidence of that so far.

I live near a Tru-Value Hardware so I'll see if they sell it and compare the PC-7 with the JB Weld to see which might give me a better temporary patch on the leaky housing. Thanks for the tip and the good luck!

 

Do a google search for LKQ Corp. Give them a call, or have a shop you trust do it. They have a nationwide network of yards, and will ship an axle to your shop of choice no charge. I run a body shop, and have bought engines, axles, ect many time this way. A year or so we were rebuilding a totaled Taco for one of the employees, that truck needed a drive shaft. No local yard had one. My cost for a new one from the dealer was about $1000.00. Called LKQ, had on shipped in from a southern state, in great shape, for $65.00

 

When I talked with LKQ months ago, Keith, they would not give me any warranty of any rear end that wasn't an exact match to what was in there, i.e. an elocking diff, and all they had available at the time was a non-locking 4.30 I think was from Michigan (which has as bad salt and weather as MA does).

In any event, I'm way past having a shop do it. I've got all the parts now (afaik) and just have to reassemble them after cleaning them up.

So now I'm trying to find a cleaner to remove any trace of oil from the housing that the oil was leaching through (brake fluid is out, I'm considering MAF sensor cleaner) and trying to decide if using JB Weld is a good option to seal it before spraying primer on it, and if so, how thick a coating I should use: thin film, 1/32" or 1/16" or more.

 

This seems like a recipe for disaster. If the metal is so rusted that its leeching oil, it's been compromised in a serious way. You have the diff and your axles. Someone from a less rusty state could ship you a bare housing for a reasonable rate.

 

I did a search on car-part.com (searches junk yards) for a 410 gear rear end in mass and found 3 for under 300
Edit: didn't see the 430 gear part but didn't find any 430s in ma but it did find them all over the north east pretty cheap