I have a 2001 4Runner and my rear differential has pinhole leaks because it is rusted out... unbelievable. This truck was VERY well taken care of, undercarriage wash at least twice a week in the winter. I have a '94 that wasn't nearly treated as kindly and it still has factory paint on the dif, WTF Toyota is going on? Was Dana corp responsible for rustproofing the rear dif? How is it possible that the differential on a 4WD vehicle is so thin that it could rot through?

I love Toyota's, I have 5 of them. My most recent purchase, a 2006 Tacoma has already been in the shop 2 times for TSB's, tailgate, rear suspension and my wheels corroded at 20,000 miles. Might be time to ditch Toyota, obviously they aren't made nearly as well as my '77 Land Cruiser

 

My 95 did the same thing. I'm wondering how I'm going to fix this. I don't have a welder yet, I'm thinking JB Wield for now...

 

Wow. Thats horrible. My '95 has been a Chicago truck all its life and the A-Arm are starting to rust though in little spots, but my rear axle is solid. And so is my frame, but the rear wheel wells, not so much.

 

I just got Mine a few months ago and she has not been taken care of. I had to replace both lower A arms. You could poke holes in them with your finger.

 

I have seen at least two 4Runners at the dealership up here (lots of snow and salt) with the rear differential rotted out. Sorry to say! It's not the thickness but I assume the vicious amounts of salt used on the roads. Same for the wheels; there's a HUGE stack out back that have been replaced under warranty because they began to corrode. New vehicles we're talking about.

 

I've seen the stacks of rotted rears at the local Toy dealership as well....such a shame.

 

I dont know why you guys seem surprised that everyone takes the cheap easy route now days. Last year A few miles from my home town they just built a brand new school, it snowed and the roof caved in, across the street was a 100 year old barn still standing with the roof intact. Goes to show how things are being built now days. CHEAP and FAST.

 

Dana didn't touch your 4runner or any part of it. 4runners are completely from japan.

 

And who knows where the metal comes from??? China?

 

I dont care how good the metal is, lots of salt will corrode it away period....

 

I just don't understand then why my '94 Toyota Truck and my '95 Celica both still have the original paint on the rear differential. My truck has seen a lot more winters than my 4Runner.

I was told that the sheet metal on the FJ40's was recycled from Japanese battleships that were used in salt water and that's why they rotted away so quickly. Wonder what the excuse would be for the steel used in a 2001 vehicle.

 

I think it's just different types of metal, different techniques in making it, in different years. The underside of my 92 pickup is in much better shape than my 95 4Runner.

If in fact that the 40's were recycled from battle ships I'd think they'd be stronger and less prone to rust. Heck that steel has to be like 6" thick at least.

 

my 99 4runner ltd w/locker I owned since day 1, 185,000+, and have used as a salty-crusty-new england snowbank crashing machine...and scrape the pumpkin now and then (oh 10 times a year) driving up tote roads....and do not ever wash it...never....

the pumpkin has no rust. axle has some, pumpkin does not.

so.....who knows ?

 

I see alot of posts about rust issues on Toyotas. When I was researching to buy my 4Runner, one of the most common complaints I read about was rust. I live in a Northern Climate, where road salt is used liberally during the winter months. I took the dirty road, and rust proofed mine. Every year, I oil spray the entire undercarriage, and also spray into my doors, inside the fenders, rear hatch, and hood. As a result, my 98's undercarriage has minimal rust, and the truck's paint is still original! I also wax the truck once a year with Nu Finish Once a year car polish! I definately recommend oil spraying your rig, at the vary least, get underneath it, and put some grease on all of the undercarriage. It's time consuming, but definately worth the return!!

 

Thread cleared of needless banter. Lets shall we?

 

None of my 4Runners and my current Tacoma has even a hint of rust. We get tons of salt in the winters, too.

 

if you live in salted area's... invest in undercoating!!! Any unprotected metal is gonna rust. once a year i power wash underneath my truck and spray on some undercoat.

 

I've heard of waxoyl, is that what most of you use? I'm sure some of you must have some home made concoctions that work well. I don't want to undercoat because I've heard it can trap the moisture in.

 

So have you determined how you are going to go about fixing it?

 

I'm going to try some POR13 Por Patch. I've used it before and it seems to work well. Is supposedly impervious to chemicals.