'02 rear differential rustout

[scargo]

Hi all, it's my first time here, just found this forum and I have an '02 4Runner with a rusted out rear differential housing.

I was noticing the smell of gear oil at the rear of the truck and crawled under to take a look. The bottom/rear of the differential housing was wet, and at first I thought maybe the drain plug was loose, although I have never touched it. Upon closer inspection it appeared that the oil was leaking out from the rear of the differential casing, in an area where there are no seals, seams, drains, etc. It was pretty rusty and covered with scale, after I chipped away all the scale with a pick hammer a drip started.

I still find it hard to believe, but the netal had actually rusted through and there are a bunch of small pinholes where the oil is leaking out. The metal is so thin that a few gentle taps with a punch makes a hole. This is my 4th Toyota truck and while I've resigned my self to accepting the inherrent body/bumper rust issues I have never seen any rust through like this before. The body is in excellent shapr, but everything underneath is very badly rusted/scaled.

So, my question is has anyone else here experienced this? Obviously the warranty has long expired but if anyone else has been here, were you able to get any help/goodwill warranty from Toyota? I'm not looking forward to replacing the entire rear axle housing and swapping over all the brakes, suspension, etc.

Any suggestions?

 

[trd_4runnin]

A buddy of mine experienced this on his Toyota also, although it was a 93 T100. His was a clean truck though, with not a lot of rust and I was a bit surprised to see this happen. He didn't go to Toyota about this, but again it was a 1993. He tried a couple different methods of fixing the original housing, all of which ended up failing and just buying a complete housing. Maybe easier for your to try and find a complete rear axle assembly?

 

[scargo]

'02 rear diff rustout

Hi all, it's my first time here, just found this forum and I have an '02 4Runner with a rusted out rear differential housing.

I was noticing the smell of gear oil at the rear of the truck and crawled under to take a look. The bottom/rear of the differential housing was wet, and at first I thought maybe the drain plug was loose, although I have never touched it. Upon closer inspection it appeared that the oil was leaking out from the rear of the differential casing, in an area where there are no seals, seams, drains, etc. It was pretty rusty and covered with scale, after I chipped away all the scale with a pick hammer a drip started.

I still find it hard to believe, but the netal had actually rusted through and there are a bunch of small pinholes where the oil is leaking out. The metal is so thin that a few gentle taps with a punch makes a hole. This is my 4th Toyota truck and while I've resigned my self to accepting the inherrent body/bumper rust issues I have never seen any rust through like this before.

So, my question is has anyone else here experienced this? Obviously the warranty has long expired but if anyone else has been here, were you able to get any help/goodwill warranty from Toyota? I'm not looking forawrd to replaving the entire rear axle housing and swapping over all the beakes, suspension, etc.

Any suggestions?

 

[shootmymime]

JUNKYARDS BABY!

 

[jharris2]

Duplicate threads merged

See Rule 8.

 

[steezemcqueen]

i have the same problem. the only other part of my truck that has rust are the bumpers
i thought about cleaning off the oil really well and coating the whole thing in either POR15 or some rhinoliner. i want to replace the whole rear axle but i have a really rare 4runner so finding the right one is going to be difficult

as of now, i'm just putting a bottle of Lucas in it every 3 weeks

 

[mcolliga]

I am having a similar problem with my '99 SR5 3.4L. The rust is pretty bad but I think there is still a lot of metal left. I'm working on getting all the loose rust off and applying several coats of 3M rubberized Undercoating.

 

[pat161]

i have the same problem. the only other part of my truck that has rust are the bumpers
i thought about cleaning off the oil really well and coating the whole thing in either POR15 or some rhinoliner. i want to replace the whole rear axle but i have a really rare 4runner so finding the right one is going to be difficult

as of now, i'm just putting a bottle of Lucas in it every 3 weeks

The axles are pretty much all the same, I see you have a 3rz so you probably have the 4.56 gearing like my old 00 2.7 had, I'll assume that's what you mean by rare. The only difference in axles is between a locked and unlocked version, you could get any axle assembly and then just buy a gear kit and swap them in.

 

[steezemcqueen]

i also don't have abs. i've looked around a bit and haven't been able to find anything that matches

 

[pat161]

Even if you get an axle originally equipped with abs all you'll be missing is a plug for the sensors, you should still be able to use the axle itself.

 

[steezemcqueen]

ah. i was told i basically needed to find the exact 4runner as mine in order to use the axle. thanks for letting me know otherwise. that makes my search alot easier!

 

[scargo]

Well, here's the update. I cleaned off all the scale and rust to see exactly where the leak was. There were two pin-head sized holes, both in the thinner rear panel of the differential housing. Both were in the center, one about an inch below where the brake cable bracket is welded on, and the other directly below about an inch from the bottom.

I considered getting a used axle and swapping over all the components, but I have a few too many other projects at the moment. So, I decided to try to patch it - I figured there was nothing to lose, if it works that's great, if not I'm no worse off.

I cleaned up the whole area around the leaks and de-greased it well. I then applied a coat of JB Weld over the two leaks. After leting that cure for a day I sanded it to rough it up and then put another coat over a larger area where it seemed thin. This stuff is chemical and resistant, basically an epoxy with a filler additive so it fills gaps and stays put. It's sandable and machineable when cured.

I know it's the cheap/quick way out but I think it may last a long time. I patched a crack in the water jacket of the engine block on my boat with this stuff back in 1989 and it is still holding.

So, I have a short-term, and possibly long-term fix for about $10 in materials and a few hours time. I'll watch it for leaks but so far, so good.

I hope this helps some others here, thanks for the views and suggestions. BTW, this truck has 95K and has needed nothing except front rotors and pads and a set of plugs so far.

 

[JmaddogT]

I am also in the same position as a few of you. I am a new member and this being my first post I fell like I should explain as much as I can. I recentley pursched a 2002 SR5 and after a week of driving it I noticed the rear end leaking from the diff. After inspecting I noticed a pin hole sized leak directley in the rear center of the cover. I feel like a moron for not noticing it sooner when i bought the vehicle and now dont feel like spending the money to replace the rear end with it only being a week old to me. I am pretty good with building and fixing cars so my plan is to repair the leak. My plan is to remove the gear oil, clean and wire brush the entire cover, then JB weld a small patch over the hole. After doing this I plan on putting some kind of spray adheasive/seal over the entire cover. My plan is to start tonight and I am goign to take pictures and post step by step on here because it seems like this is a problem that quite a few of us are having. If anyone else has tried anythign that has worked please let me know.