Rear differential rust

[Mark_BC]

I've owned this '02 4Runner Sport Edition in Maine since new. It is well cared for, by the book and beyond, with no body rust and runs great at 186,000 miles. Even with undercarraige washing at every snow storm and a complete under body power wash and re-rust proofing in 2011, the rear diff rusted out, was flaking metal and leaking severely.

All the Toyota dealers solutions were to spend $2500+ for a new rear axle housing with the same junk metal cover. The T4R site put me onto Barnes 4WD LLC and their 1/4 inch thick steel replacement differential covers. I found a welder who was confident he could do the work. He welded the cover and although it was a tight fit he said it was a perfect fit and went in smoothly, just clearing the sport edition rear traction bar and emergency brake cable. Some minor adjustment for clips on the original stock diff, and the work was done in a few hours and saved $2000. Pics attached. A little more welding to a few spots on the frame , a new power wash and a a rust inhibitor undercoat and another few years for the 4 Runner----thanks to Barnes 4WD LLC ! If no Barnes, then no more 4Runner.

The Diff Cover price was reasonable. It shipped quickly. The quality was as advertised. In Southern Maine talk to Zack @ [207]-615-6934

Thanks Barnes for solving Toyotas' problem for them. By the way-TMC would not acknowledge the rusting out diff covers were a problem rising to the level of a recall.

I ordered and just received my Barnes cover plate. Did you take the third member out and weld from the inside also? I have read of people just welding it on with all the gears in there.

It is interesting because our truck sat one winter unused with road salt underneath for the whole winter while it rusted. I looked underneath and it looked terrible but further inspection reveals the frame is in great shape with only minor surface flaking on the outside, most of the paint intact, and if you put your fingers in the holes you can feel that the paint inside is virtually perfect.

Most of the suspension members were rusted pretty bad, going through and fixing / replacing that now. The diff cover plate rusted through with one pinhole leak, there is definitely something wrong with the metallurgy there. I put a screw driver through another spot removing rust. JB Weld is working fine for now until I can put the cover plate on, I want to do it right.

Edit: yours is shaped like a box, mine is more like the original, like a bowl, but beefier. Wonder why the difference.

 

[NVAGVUP]

Square Diff Cover.

The Barnes site specifically identified the FLAT cover as the correct one for a 2002 4Runner. Check back with Barnes via email. Running now for a week with no issues on new diff. Welder did not drop the axle assembly to do the work. Requires careful cleaning and flush before refill.

 

[NVAGVUP]

I ordered and just received my Barnes cover plate. Did you take the third member out and weld from the inside also? I have read of people just welding it on with all the gears in there.

It is interesting because our truck sat one winter unused with road salt underneath for the whole winter while it rusted. I looked underneath and it looked terrible but further inspection reveals the frame is in great shape with only minor surface flaking on the outside, most of the paint intact, and if you put your fingers in the holes you can feel that the paint inside is virtually perfect.

Most of the suspension members were rusted pretty bad, going through and fixing / replacing that now. The diff cover plate rusted through with one pinhole leak, there is definitely something wrong with the metallurgy there. I put a screw driver through another spot removing rust. JB Weld is working fine for now until I can put the cover plate on, I want to do it right.

Edit: yours is shaped like a box, mine is more like the original, like a bowl, but beefier. Wonder why the difference.

How did the install of the Barnes Rear Diff Cover go? Mine was welded on with gears in place once the diff was cleaned out post cutting wheel work. 1,000miles later no problems, no noises, .

Now have to find out why every time it rains the idiot lights go xmas tree and flash on flash off but then go dark when it dries out. Doesn't seem to affect performance other than loss of VSC and Tracs. Drove to Montreal and back with this condition and idiot lights finally went off at about 500 miles into the trip. Went in for a yearly state inspection and thank god the lights never came on because check engine is a fail.

 

[Jzxrunner]

Damn, my whole rear is surface rusted to shit this makes me want to take it off and catch it now haha

 

[Mark_BC]

How did the install of the Barnes Rear Diff Cover go? Mine was welded on with gears in place once the diff was cleaned out post cutting wheel work. 1,000miles later no problems, no noises

Haven't done it yet. The JB Weld is holding. That is my mom's 4runner so it is taking back seat to my "new" one which also has a rusty differential. Had to do way more chipping than I expected and thankfully didn't poke through. I painted it up. I am doing a road trip through California over the holidays so I'm hoping to pick up a whole new rear axle with e-locker for mine. My mom's will stay on, I'll just weld the new plate on. I just bought a Lincoln Mig Pak 140 welder so I'll start practise welding.